CN118265711A - Chromanamidine monocyclic lactam antibiotics - Google Patents

Abstract

The present invention relates to a monocyclic lactam compound of formula I. The present invention also relates to a pharmaceutical composition comprising a monocyclic lactam compound of structural formula I or a pharmaceutically acceptable salt thereof. The present invention further relates to a compound of formula (I) for use in a method for treating bacterial infection, which is used alone or in combination with a therapeutically effective amount of a second β-lactam antibiotic. The present invention discloses the synthesis and characterization of exemplary compounds and their bioassays. Exemplary compounds are, for example, (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((S)-pyrrolidin-3-yl)amidino)benzodihydropyran-2-yl)propionic acid (Example 7; Compound 1).

Description

Benzodihydropyranamidine monobactam antibiotics

Technical Field

The present invention relates to novel monobactam compounds, methods for preparing the same and their use as therapeutic agents. In particular, the present invention relates to monobactam compounds useful as antibiotics for treating bacterial infections.

Background technique

The introduction of antibiotics to treat bacterial infections was one of the greatest medical achievements of the 20th century. However, over the past few decades, bacteria resistant to multiple antibiotics have begun to emerge around the world, threatening the effectiveness of antibiotic treatment. In the United States alone, at least 23,000 people die each year directly from infections caused by antibiotic-resistant bacteria, and many others die from pre-existing conditions exacerbated by similar infections. Antibiotic Resistance Threats in the United States, 2013, Centers for Disease Control, Atlanta, Georgia. New antibiotics are needed to combat current and future threats of multidrug-resistant bacteria.

β-lactams are the most widely used antibiotics for the treatment of serious bacterial infections. They include carbapenems, cephalosporins, penicillins and monobactams. As observed in other antibiotic classes, resistance to β-lactams has emerged. For most Gram-negative bacteria, this resistance is mainly driven by the expression of β-lactamases (an enzyme that hydrolyzes β-lactam compounds). There are 4 different classes of β-lactamases (A, B, C and D) that can hydrolyze overlapping but different subsets of β-lactams (Drawz and Bonomo, Clin. Micro. Rev., 2010, 23: 160–201). Although class B β-lactamases (also known as metallo-β-lactamases (MBLs)) are not the most prevalent β-lactamases found clinically, their frequency and distribution are increasing and present a significant medical threat because (i) MBLs have the ability to hydrolyze all β-lactams except monobactams and (ii) unlike class A and C β-lactamases, class B β-lactamases have no available inhibitors.

Aztreonam is a monobactam that was first approved in the United States in 1986 for the treatment of aerobic Gram-negative bacterial infections and is still the only monobactam used in the United States. However, aztreonam has low activity against Pseudomonas and Acinetobacter strains. Due to the inherent anti-MBL hydrolysis ability of monobactams, some companies have begun to develop new monobactam compounds for the treatment of infections caused by Gram-negative bacteria. WO 2007/065288, WO2012/073138, J.Medicinal Chemistry 56:5541-5552 (2013) and Bioorganic and Medicinal Chemstry Letters 22:5989 (2012) disclose monobactam compounds containing a siderophore portion.

WO 2019/070492 discloses benzodihydropyran monocyclic lactam compounds for treating bacterial infections. WO2017/106064 discloses biaryl monocyclic lactam compounds and their use in treating bacterial infections. WO 2013/110643 discloses novel amidine-substituted monocyclic lactam derivatives and their use as antimicrobial agents. WO 2015/103583 discloses monocyclic lactam derivatives that can be used to treat infectious diseases (i.e., bacterial infections). U.S. Patent Application Publication Nos. US2015/0045340 and US 2014/0275007 disclose oxamazin monocyclic lactams and their use as antibacterial agents. U.S. Patent Application Publication No. US2015/0266867 discloses novel monocyclic lactam compounds used as antibacterial agents.

There is a continuing need for new antibiotics to overcome multidrug resistance. The compounds disclosed in the present invention are designed to meet this medical need by administration alone or in combination with suitable β-lactamase inhibitors.

Summary of the invention

The present invention relates to the design and synthesis of monobactam analogs, which are a new class of potent antibiotics that are effective against a wide range of Gram-negative bacteria. These compounds and their pharmaceutically acceptable salts can be used as therapeutic agents for the clinical treatment of various infections caused by Gram-negative bacteria (including multidrug-resistant strains). The compounds can be used alone or in combination with suitable β-lactamase inhibitors. The present invention includes compounds of formula I:

and pharmaceutically acceptable salts thereof.

The present invention also relates to a pharmaceutical composition for treating bacterial infection (including infection by multidrug-resistant Gram-negative bacterial strains) in a subject, comprising a monobactam compound of structural formula I or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier, diluent or excipient.

The compounds of formula (I) (also referred to herein as "monobactam compounds") and their pharmaceutically acceptable salts can be used, for example, to inhibit the growth of Gram-negative bacterial strains (including but not limited to Pseudomonas, Klebsiella and Acintetobacter strains, including Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii), and/or to treat or prevent their clinical manifestations in patients.

The present invention also relates to a method for treating a Gram-negative bacterial infection in a subject in need of treatment, comprising administering to the subject an effective amount of a monobactam compound of the present invention. In a specific embodiment of the present invention, the method comprises administering a β-lactamase inhibitor compound. Embodiments, sub-embodiments and features of the present invention are either further described in the subsequent description, examples and appended claims, or are obvious from the subsequent description, examples and appended claims.

Detailed ways

The present invention relates to novel compounds of structural formula I:

or a pharmaceutically acceptable salt thereof, wherein:

T is CH or N, provided that no more than two of T, U and V are N;

U is CH or N;

V is CH or N;

X is selected from the group consisting of

1) O, and

2) CH ₂ ;

Y is selected from the group consisting of:

1) O,

2) NR ⁸ ,

3) S, and

4) CH ₂ ,

Provided that when Y is O, NR ⁸ or S, X is not O;

Z is

1) O,

2) S,

3) CH ₂ , or

4) NH,

Provided that when Z is O, S or NH, X is not O;

W is selected from the group consisting of:

1) key, and

2) O;

Q is selected from the group consisting of:

1) N, and

2)CR ⁸ ;

^R1 is selected from the group consisting of:

1) -C _3-12 cycloalkyl,

2) -C _3-12 cycloalkenyl,

3) -C _2-11 cycloheteroalkyl,

4) -C _2-11 cycloheteroalkenyl,

5) aryl, and

6) heteroaryl,

wherein alkyl, cycloalkyl, cycloalkenyl, cycloheteroalkyl, cycloheteroalkenyl, aryl and heteroaryl are unsubstituted or substituted with one to five substituents selected from ^Ra ;

^R2 is selected from the group consisting of:

1) Hydrogen,

2) C _1-6 alkyl,

3) C _1-6 alkyl-OR ⁴ , and

4) C _1-6 alkyl-NHR ⁴ ,

wherein the alkyl group is unsubstituted or substituted with one to three halogens;

^R3 is selected from the group consisting of:

1) Hydrogen, and

2) OH;

^R4 is selected from the group consisting of:

1) Hydrogen,

2) C _1-3 alkyl, and

3) C ₃ cycloalkyl,

wherein alkyl and cycloalkyl are unsubstituted or substituted with one to three halogen or OC _1-3 alkyl;

^R5 is selected from the group consisting of:

1) -CO ₂ H, and

2) Tetrazole;

^R6 and ^R7 are selected from the group consisting of:

1) Hydrogen, and

2) C _1-6 alkyl,

wherein alkyl is unsubstituted or substituted with one to three halogens, provided that at least one of R ⁶ and R ⁷ is hydrogen;

^R8 is independently selected from the group consisting of:

1) Hydrogen,

2) C _1-4 alkyl,

3) halogen, and

4) C _3-7 cycloalkyl,

wherein alkyl and cycloalkyl are unsubstituted or substituted with one to three substituents selected from: -OH, halogen, NH ₂ and -OC _1-3 alkyl;

^R9 and ^R10 are selected from the group consisting of:

1) Hydrogen, and

2) C _1-6 alkyl,

wherein alkyl is unsubstituted or substituted with one to three substituents selected from halogen, OH, -OC _1-3 alkyl, -NHC(O)C _1-3 alkyl, -C(O)NHC _1-3 alkyl, NHC _1-3 alkyl and SC _1-3 alkyl, provided that one or both of R ⁹ and R ¹⁰ are C _1-6 alkyl,

Alternatively, R ⁹ and R ¹⁰ together with the carbon to which they are attached form a monocyclic C _3-5 cycloalkyl or a monocyclic C _2-5 cycloheteroalkyl, wherein the cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with one to three substituents independently selected from halogen, -OH and -OC _1-3 alkyl;

Each Ra ^is independently selected from the group consisting of:

1) Halogen,

2) -C _1-6 alkyl,

3) -C _0-6 alkyl-OC _1-6 alkyl,

4) –C _0-6 alkyl-OH,

5) -C _0-6 alkyl S(O) _r R ^j ,

6) -C _0-6 alkylS(O) _r NR ^k R ^l ,

7) -C _0-6 alkyl C(O)R ⁱ ,

8) -C _0-6 alkyl OC(O)R ⁱ ,

9) -C _0-6 alkyl C(O)OR ⁱ ,

10) -C _0-6 alkylCN,

11) -C _0-6 alkyl C(O)NR ^k R ^l ,

12) -C _0-6 alkyl C(NH)NR ^k R ^l ,

13) -C _0-6 alkyl NR ^k R ^l ,

14)-C _0-6 alkyl N(R ^k )(C(O)R ⁱ ),

15)-C _0-6 alkyl N(R ^k )(C(O)OR ^h ),

16)-C _0-6 alkyl N(R ^k )(C(O)NR ^f R ^g ), and

17)-C _0-6 alkyl N(R ^k )(S(O) _v R ^j ),

wherein alkyl is unsubstituted or substituted with one to three substituents selected from halogen, OH, -OC _1-3 alkyl, -C _1-3 alkyl, -CO ₂ C _1-3 alkyl, -C(O)NH ₂ , -C _0-6 alkylNH ₂ and -C _0-6 alkylNH(C _1-3 alkyl);

Each ^{Rb is} independently selected from the group consisting of:

1) Hydrogen,

2) C _1-6 alkyl,

3) C _0-6 alkyl-OC _1-6 alkyl,

4) C _0-6 alkyl-OH,

5) C _0-6 alkyl-S(O) _u R ^d ,

6) C _1-6 alkyl-C(ON(R ^e ) ₂ ,

7) C _1-6 alkyl N(R ^e )C(O)R ^e ,

8) C _0-6 alkyl-N(R ^e ) ₂ , and

9) Halogen,

wherein alkyl is unsubstituted or substituted with one to three halogens, or wherein two ^Rb substituents together with the atoms to which they are attached can cyclize to form a 3 to 6 membered ring;

Each R ^c is independently selected from the group consisting of:

1) Hydrogen,

2) C _1-6 alkyl,

3) C _0-6 alkyl-OC _1-6 alkyl,

4) C _0-6 alkyl-OH,

5) C _0-6 alkyl-S(O) _v R ^f ,

6) C _0-6 alkyl-S(O) _v N(R ^g ) ₂ ,

7) C _1-6 alkyl C(O)-N(R ^g ) ₂ ,

8) C _1-6 alkyl N(R ^g )C(O)R ^g ,

9) C _0-6 alkyl-N(R ^g ) ₂ , and

10) Halogen,

wherein the alkyl group is unsubstituted or substituted with one to three halogens;

Each Rd ^is independently selected from the group consisting of:

1) Hydrogen, and

2) -C _1-6 alkyl,

wherein each alkyl group is unsubstituted or substituted with one to three halogens;

Each Re ^is independently selected from the group consisting of:

1) Hydrogen, and

2) -C _1-6 alkyl,

wherein each alkyl group is unsubstituted or substituted with one to three halogens;

Each ^Rf is independently selected from the group consisting of:

1) Hydrogen, and

2) -C _1-6 alkyl,

wherein each alkyl group is unsubstituted or substituted with one to three halogens;

Each ^Rg is independently selected from the group consisting of:

1) Hydrogen, and

2) -C _1-6 alkyl,

wherein each alkyl group is unsubstituted or substituted with one to three halogens;

Each Rh ^is independently selected from the group consisting of:

1) Hydrogen, and

2) -C _1-6 alkyl,

wherein each alkyl group is unsubstituted or substituted with one to three halogens;

Each R ⁱ is -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted with one to three halogens;

Each ^Rj is independently selected from the group consisting of:

1) Hydrogen,

2) OH, and

3) -C _1-6 alkyl,

wherein each alkyl group is unsubstituted or substituted with one to three halogens;

Each R ^k is independently selected from the group consisting of:

1) Hydrogen, and

2) -C _1-6 alkyl,

wherein each alkyl group is unsubstituted or substituted with one to three halogens;

Each ^{R1 is} independently selected from the group consisting of:

1) Hydrogen, and

2) -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted with one to three halogens;

Each r is independently 0, 1 or 2;

Each s is independently 0, 1, 2, 3, 4 or 5;

Each t is independently 0, 1, 2 or 3;

Each u is independently selected from 0, 1 or 2; and

Each v is independently selected from 0, 1 or 2.

The present invention relates to novel monobactam analogs, a class of highly effective antibiotics that are effective against a wide range of Gram-negative bacteria. These compounds can be used as therapeutic agents for the clinical treatment of various infections caused by Gram-negative bacteria (including multidrug-resistant strains), as well as for the treatment or prevention of clinical pathologies associated therewith.

Unless otherwise indicated, in each of the various embodiments of compounds of the invention described herein, including formula (I) and the various embodiments thereof, each variable in the embodiment is selected independently of the other variables.

The present invention includes each diastereomer, enantiomer and diastereomer of the compound of formula (I) and the compound of formula (I), and mixtures of diastereomers and/or enantiomers thereof, including racemic mixtures. The present invention also includes any solvates, hydrates, stereoisomers and tautomers of the compound of formula (I) and any pharmaceutically acceptable salt thereof.

In one embodiment of the invention, T is CH or N, provided that no more than two of T, U and V are N; U is CH or N; and V═CH or N.

In another embodiment of the invention, T is CH or N, provided that no more than two of T, U and V are N. In one class of this embodiment, T is CH or N. In another class of this embodiment, T is CH. In another class of this embodiment, T is N.

In another embodiment of the present invention, U is CH or N. In a class of this embodiment, U is CH. In another class of this embodiment, U is N.

In another embodiment of the present invention, V═CH or N. In a class of this embodiment, V is CH. In another class of this embodiment, V is N.

In another embodiment of the present invention, T, U and V are CH.

In another embodiment of the invention, W is a bond or O. In a class of this embodiment, W is a bond. In another class of this embodiment, W is O.

In another embodiment of the present invention, Q is N or CR ⁸ . In a class of this embodiment, Q is N. In another class of this embodiment, Q is CR ⁸ .

In another embodiment of the present invention, X is O or _CH2 . In a class of this embodiment, X is O. In another class of this embodiment, X is _CH2 .

In another embodiment, Y is O, NR ⁸ , S or CH ₂ , provided that when Y is O, NR ⁸ or S, X is not O. In another embodiment, Y is O, NR ⁸ , S or CH ₂ , provided that when Y is O, NR ⁸ or S, X is CH ₂ .

In another embodiment, Y is O, NR ⁸ , S, or CH ₂ . In one class of this embodiment, Y is O or CH ₂ . In another class of this embodiment, Y is NR ⁸ or S. In another class of this embodiment, Y is O. In another class of this embodiment, Y is NR ⁸ . In another class of this embodiment, Y is S. In another class of this embodiment, Y is CH ₂ .

In another embodiment, Z is O, S, _CH2 , or NH, provided that when Z is O, S, or NH, X is not O. In one class of this embodiment, Z is O, S, _CH2 , or NH. In another class of this embodiment, Z is O or _CH2 . In another class of this embodiment, Z is S or NH. In another class of this embodiment, Z is S. In another class of this embodiment, Z is _CH2 . In another class of this embodiment, Z is NH. In another class of this embodiment, Z is O.

In another embodiment of the present invention, R ¹ is selected from

R ¹ is selected from the group consisting of: -C _3-9 cycloalkyl, -C _2-8 cycloheteroalkyl, C _2-8 cycloheteroalkenyl, aryl and heteroaryl, wherein cycloalkyl, cycloalkenyl, cycloheteroalkyl, cycloheteroalkenyl, aryl and heteroaryl are unsubstituted or substituted with one to five substituents selected from ^Ra .

In another embodiment of the present invention, R ¹ is selected from the group consisting of: -C _3-9 cycloalkyl, C _2-7 cycloheteroalkyl, aryl and heteroaryl, wherein cycloalkyl, cycloheteroalkyl, aryl and heteroaryl are unsubstituted or substituted with one to five substituents selected from ^Ra .

In another embodiment of the present invention, R ^is selected from the group consisting of: -C _3-9 cycloalkyl, C _2-8 cycloheteroalkyl and aryl, wherein cycloalkyl, cycloheteroalkyl and aryl are unsubstituted or substituted with one to five substituents selected from ^Ra . In a class of this embodiment, R ^is selected from the group consisting of: cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, bicyclo[1.1.1]pentane, bicyclo[3.1.1]heptane, bicyclo[4.1.0]heptane, bicyclo[2.2.2]octane, spiro[3.3]heptane, spiro[3.5]nonane, spiro[2.3]hexane, azetidine, pyrrolidine, piperidine, azepane, 2-oxabicyclo[2.1.1]hexane, 3 -azabicyclo[3.1.0]hexane, 3-azabicyclo[3.2.1]octane, 8-azabicyclo[3.2.1]octane, 2-azaspiro[3.5]nonane, 2-azaspiro[3.3]heptane, 3-azabicyclo[3.2.0]heptane, 1-azaspiro[3.3]heptane, 6-azaspiro[3.5]nonane, 7-azaspiro[3.5]nonane, 6-azaspiro[3.4]octane and phenyl, wherein R ^is unsubstituted or substituted with one to five substituents selected from ^Ra .

In another embodiment of the present invention, R ¹ is aryl, wherein aryl is unsubstituted or substituted with one to five substituents selected from ^Ra . In a class of this embodiment, R ¹ is phenyl, wherein phenyl is unsubstituted or substituted with one to five substituents selected from ^Ra .

In another embodiment of the present invention, R ^is selected from the group consisting of: -C _3-9 cycloalkyl and C _2-8 cycloheteroalkyl, wherein the cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with one to five substituents selected from ^Ra . In a class of this embodiment, R ^is selected from the group consisting of: cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, bicyclo[1.1.1]pentane, bicyclo[3.1.1]heptane, bicyclo[4.1.0]heptane, bicyclo[2.2.2]octane, spiro[3.3]heptane, spiro[3.5]nonane, spiro[2.3]hexane, azetidine, pyrrolidine, piperidine, azepane, 2-oxabicyclo[2.1.1]hexane [3.3]heptane, 3-azabicyclo[3.2.0]heptane, 1-azaspiro[3.3]heptane, 6-azaspiro[3.5]nonane, 7-azaspiro[3.5]nonane, and 6-azaspiro[3.4]octane, wherein R ^is unsubstituted or substituted with one to five substituents selected from ^Ra . In another class of this embodiment, in a class of this embodiment, R is selected from the group consisting of cyclobutane, cyclohexane, cycloheptane, bicyclo[4.1.0]heptane, piperidine, and azepane, wherein ^R is unsubstituted or substituted with one to ^five substituents selected from ^Ra .

In another embodiment of the present invention, R ^is selected from the group consisting of: -C _3-9 cycloalkyl, wherein the cycloalkyl is unsubstituted or substituted by one to five substituents selected from R ^a . In one class of the present embodiment, R is ^selected from the group consisting of: cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, bicyclo [1.1.1] pentane, bicyclo [3.1.1] heptane, bicyclo [4.1.0] heptane, bicyclo [2.2.2] octane, spiro [3.3] heptane, spiro [3.5] nonane and spiro [2.3] hexane, wherein ^R is unsubstituted or substituted by one to five substituents selected from R ^a . In another class of the present embodiment, R ^is selected from the group consisting of: cyclobutane, cyclohexane, cycloheptane and bicyclo [ ^4.1.0 ] heptane, wherein R is unsubstituted or substituted by one to five substituents selected from R ^a . In another class of this embodiment, R is ^cyclobutane , wherein ^R is unsubstituted or substituted with one to five substituents selected from ^Ra . In another class of this embodiment, ^R is cyclohexane, wherein R ^is unsubstituted or substituted with one to five substituents selected from ^Ra . In another class of this embodiment, ^R is bicyclo[4.1.0]heptane, wherein R ^is unsubstituted or substituted with one to five substituents selected from ^Ra . In another class of this embodiment, ^R is cycloheptane, wherein ^R is unsubstituted or substituted with one to five substituents selected from ^Ra .

In another embodiment of the present invention, R ¹ is C _2-7 cycloheteroalkyl, wherein the cycloheteroalkyl is unsubstituted or substituted with one to five substituents selected from ^Ra . In a class of this embodiment, R ^is selected from the group consisting of azetidine, pyrrolidine, piperidine, azepane, 2-oxabicyclo[2.1.1]hexane, 3-azabicyclo[3.1.0]hexane, 3-azabicyclo[3.2.1]octane, 8-azabicyclo[3.2.1]octane, 2-azaspiro[3.5]nonane, 2-azaspiro[3.3]heptane, 3-azabicyclo[3.2.0]heptane, 1-azaspiro[3.3]heptane, 6-azaspiro[3.5]nonane, 7-azaspiro[3.5]nonane and 6-azaspiro[3.4]octane, wherein R ^is unsubstituted or substituted with one to five substituents selected from ^Ra . In another class of this embodiment, R is selected from the group consisting of piperidine and azepane, wherein R is ^{unsubstituted} or substituted with one to five substituents selected from ^Ra . In another class of this embodiment, R ^{is piperidine} , wherein R is ^{unsubstituted} or substituted with one to five substituents selected from ^Ra . In another class of this embodiment, R is ^azepane , wherein R ^is unsubstituted or substituted with one to five substituents selected from ^Ra .

In another embodiment of the present invention, R ^is selected from the group consisting of hydrogen, -C _1-6 alkyl, -C _1-6 alkyl-OR ⁴ and -C _1-6 alkyl-NHR ⁴ , wherein the alkyl is not substituted or replaced by one to three halogens. In one class of the present embodiment, ^R is selected from the group consisting of hydrogen and C _1-6 alkyl, wherein the alkyl is not substituted or replaced by one to three halogens. In another class of the present embodiment, R is C ^1-3 alkyl, wherein the alkyl is not substituted or replaced by one to three halogens. In another class of the present embodiment, R is C ^1-3 alkyl. In another _class of the present embodiment, ^R is hydrogen _.

In another embodiment of the present invention, ^R3 is selected from the group consisting of hydrogen and OH. In a class of this embodiment, ^R3 is OH. In another class of this embodiment, ^R3 is hydrogen.

In another embodiment of the present invention, R ⁴ is selected from the group consisting of hydrogen, -C _1-3 alkyl and C ₃ cycloalkyl, wherein alkyl and cycloalkyl are not substituted or are substituted with one to three halogens or OC _1-3 alkyl. In a class of this embodiment, R ⁴ is selected from the group consisting of hydrogen, CH ₃ and cyclopropane, wherein methyl and cyclopropane are not substituted or are substituted with one to three halogens or OC _1-3 alkyl. In another class of this embodiment, R ⁴ is selected from the group consisting of hydrogen, CH ₃ and cyclopropane.

In another embodiment of the present invention, R ⁴ is selected from the group consisting of hydrogen and C _1-3 alkyl, wherein alkyl is unsubstituted or substituted by one to three halogens or OC _1-3 alkyl. In one class of this embodiment, R ⁴ is selected from the group consisting of hydrogen and C _1-3 alkyl. In another class of this embodiment, R ⁴ is hydrogen. In another class of this embodiment, R ⁴ is C _1-3 alkyl, wherein alkyl is unsubstituted or substituted by one to three halogens or OC _1-3 alkyl. In another class of this embodiment, R ⁴ is C _1-3 alkyl. In a subclass of this category, R ⁴ is -CH ₃ .

In another class of the present invention, ^R4 is selected from the group consisting of: _C1-3 alkyl and _C3 cycloalkyl, wherein the alkyl and cycloalkyl are unsubstituted or substituted with one to three halogens or _OC1-3 alkyl. In a class of this embodiment, ^R4 is selected from the group consisting of: _C1-3 alkyl and _C3 cycloalkyl.

In another class of the invention, ^R4 is cyclopropyl, wherein the cyclopropyl is unsubstituted or substituted with one to three halogen or _OC1-3 alkyl.

In another class of the invention, ^R4 is _C1-3 alkyl, wherein alkyl is unsubstituted or substituted with one to three halogen or _OC1-3 alkyl.In one class of this embodiment, ^R4 is _C1-3 alkyl.

In another embodiment of the present invention, ^R5 is selected from the group consisting of: _-CO2H and tetrazole. In a class of this embodiment, ^R5 is tetrazole. In another class of this embodiment, ^R5 is _-CO2H .

In another embodiment of the present invention, ^R6 and ^R7 are selected from the group consisting of hydrogen and _C1-6 alkyl, wherein alkyl is unsubstituted or substituted with one to three halogens, provided that at least one of ^R6 and ^R7 is hydrogen.

In another embodiment, R ⁶ is independently selected from the group consisting of hydrogen and C _1-6 alkyl, wherein alkyl is unsubstituted or substituted with one to three halogens, provided that at least one of R ⁶ and R ⁷ is hydrogen.

In another embodiment, R is independently selected from the group consisting of the following: hydrogen and C _1-6 alkyl, wherein the alkyl is not substituted or is substituted by one to three halogens. In a class of the present embodiment, R ⁶ is C _1-6 alkyl, wherein the alkyl is not substituted or is substituted by one to three halogens. In another ^class of the present embodiment, R ⁶ is C _1-6 alkyl. In another class of the present embodiment, R ⁶ is hydrogen.

In another embodiment, R ⁷ is independently selected from the group consisting of hydrogen and C _1-6 alkyl, wherein alkyl is unsubstituted or substituted with one to three halogens, provided that at least one of R ⁶ and R ⁷ is hydrogen.

In another embodiment, ^{R is} independently selected from the group consisting of the following: hydrogen and C _1-6 alkyl, wherein the alkyl is not substituted or is substituted by one to three halogens. In a class of the present embodiment, R is C ^1-6 alkyl, wherein the alkyl is not substituted or is substituted by one to three halogens. In another class of the present embodiment, R is C ^1-6 alkyl. In another _class of the present embodiment, ^R is hydrogen _.

In another embodiment of the present invention, R ⁸ is independently selected from the group consisting of hydrogen, C _1-4 alkyl, halogen and C ₃ -C ₇ cycloalkyl, wherein alkyl and cycloalkyl are unsubstituted or substituted with one to three substituents selected from the group consisting of -OH, halogen, NH ₂ and -OC _1-3 alkyl. In one class of this embodiment, R ⁸ is independently selected from the group consisting of hydrogen, C _1-4 alkyl and halogen, wherein C ₁ -C ₄ alkyl is unsubstituted or substituted with one to three substituents selected from the group consisting of -OH, halogen, NH ₂ and -OC _1-3 alkyl. In another class of this embodiment, R ⁸ is independently selected from the group consisting of hydrogen and C _1-4 alkyl, wherein C ₁ -C ₄ alkyl is unsubstituted or substituted with one to three substituents selected from the group consisting of -OH, halogen, NH ₂ and -OC _1-3 alkyl. In another class of this embodiment, ^R is C _1-4 alkyl, wherein C ₁ -C ₄ alkyl is unsubstituted or substituted with one to three substituents selected from: -OH, halogen, NH ₂ and -OC _1-3 alkyl. In another class of this embodiment, R ^is independently selected from the group consisting of hydrogen and C _1-4 alkyl. In another class of this embodiment, ^R is hydrogen.

In another embodiment of the present invention, R ⁹ and R ¹⁰ are selected from the group consisting of: hydrogen and C _1-6 alkyl, wherein alkyl is unsubstituted or substituted with one to three substituents selected from: halogen, OH, -OC _1-3 alkyl, -NHC(O)C _1-3 alkyl, -C(O)NHC _1-3 alkyl, NHC _1-3 alkyl and SC _1-3 alkyl, with the proviso that one or both of R ⁹ and R ¹⁰ are C _1-6 alkyl, or R ⁹ and R ¹⁰ together with the carbon to which they are attached form a monocyclic C _3-5 cycloalkyl or a monocyclic C _2-5 cycloheteroalkyl, wherein cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with one to three substituents independently selected from halogen, -OH and -OC _1-3 alkyl. In one class of this embodiment, R ⁹ and R ¹⁰ are selected from the group consisting of hydrogen and C _1-6 alkyl, wherein the alkyl is unsubstituted or substituted with one to three substituents selected from the group consisting of halogen, OH, -OC _1-3 alkyl, -NHC(O)C _1-3 alkyl, -C(O)NHC _1-3 alkyl, NHC _1-3 alkyl and SC _1-3 alkyl, provided that one or both of R ⁹ and R ¹⁰ are C _1-6 alkyl. In another class of this embodiment, R ⁹ and R ¹⁰ are selected from the group consisting of hydrogen, -CH ₃ and -CH ₂ CH ₃ . In another class of this embodiment, R ⁹ and R ¹⁰ are selected from C _1-6 alkyl, wherein alkyl is unsubstituted or substituted with one to three substituents selected from halogen, OH, -OC _1-3 alkyl, -NHC(O)C _1-3 alkyl, -C(O)NHC _1-3 alkyl, NHC _1-3 alkyl, and SC _1-3 alkyl, provided that one or both of R ⁹ and R ¹⁰ are C _1-6 alkyl. In another class of this embodiment, R ⁹ and R ¹⁰ are selected from C _1-6 alkyl. In another class of this embodiment, R ⁹ and R ¹⁰ are selected from -CH ₃ and -CH ₂ CH _3. In another class of this embodiment, R ⁹ and R ¹⁰ are each -CH ₂ CH _3. In another class of this embodiment, R ⁹ and R ¹⁰ are each -CH ₃ .

In another embodiment of the present invention, R ⁹ is independently C _1-6 alkyl, wherein alkyl is unsubstituted or substituted with one to three substituents selected from the group consisting of halogen, OH, -OC _1-3 alkyl, -NHC(O)C _1-3 alkyl, -C(O)NHC _1-3 alkyl, NHC _1-3 alkyl and SC _1-3 alkyl, or R ⁹ and R ¹⁰ together with the carbon to which they are attached form a monocyclic C _3-5 cycloalkyl or a monocyclic C _2-5 cycloheteroalkyl, wherein cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with one to three substituents independently selected from the group consisting of halogen, -OH and -OC _1-3 alkyl. In another class of this embodiment, R ⁹ is independently selected from the group consisting of: C _1-6 alkyl, wherein the alkyl is unsubstituted or substituted with one to three substituents selected from: halogen, OH, -OC _1-3 alkyl, -NHC(O)C _1-3 alkyl, -C(O)NHC _1-3 alkyl, NHC _1-3 alkyl and SC _1-3 alkyl.

In another class of this embodiment, R ⁹ is independently selected from the group consisting of: C _1-6 alkyl. In another class of this embodiment, R ⁹ is independently selected from the group consisting of: -CH ₃ and -CH ₂ CH _3. In another class of this embodiment, R ⁹ is -CH ₂ CH _3. In another class of this embodiment, R ⁹ is -CH ₃ .

In another embodiment of the present invention, R ¹⁰ is independently C _1-6 alkyl, wherein alkyl is unsubstituted or substituted with one to three substituents selected from the group consisting of halogen, OH, -OC _1-3 alkyl, -NHC(O)C _1-3 alkyl, -C(O)NHC _1-3 alkyl, NHC _1-3 alkyl and SC _1-3 alkyl, or R ⁹ and R ¹⁰ together with the carbon to which they are attached form a monocyclic C _3-5 cycloalkyl or a monocyclic C _2-5 cycloheteroalkyl, wherein cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with one to three substituents independently selected from the group consisting of halogen, -OH and -OC _1-3 alkyl. In another class of this embodiment, R ¹⁰ is independently selected from the group consisting of: C _1-6 alkyl, wherein the alkyl is unsubstituted or substituted with one to three substituents selected from: halogen, OH, -OC _1-3 alkyl, -NHC(O)C _1-3 alkyl, -C(O)NHC _1-3 alkyl, NHC _1-3 alkyl and SC _1-3 alkyl.

In another class of this embodiment, R ¹⁰ is independently selected from the group consisting of: C _1-6 alkyl. In another class of this embodiment, R ¹⁰ is independently selected from the group consisting of: -CH ₃ and -CH ₂ CH ₃ . In another class of this embodiment, R ¹⁰ is -CH ₂ CH ₃ . In another class of this embodiment, R ¹⁰ is -CH ₃ .

In another embodiment of the present invention, each Ra ^is independently selected from the group consisting of halogen, _{-Ci_6alkyl} , _{-C0_6alkyl} -OCi_6alkyl, _{-C0_6alkyl} -OH, -C0_6alkylS(O) _rRj ^, _{-C0_6alkylS} (O) ^rNRkRl , _{-C0_6alkylC} (O) _Ri , _{-C0_6alkylOC} ⁽ O _{)Ri, -C0_6alkylC(O)ORi, -C0_6alkylCN, -C0_6alkylC(O)NRkRl, -C0_6alkylC} ⁽ _NH ⁾ _NRkRl ^, _{-C0_6alkylNRkRl} ^, _{-C0_6alkylN (} ^{Rk )} ₍ ^{C (} O ₎ ^Ri ), _{-C0_6alkylN} ( ^Rk )(C(O) ^ORh ) ^, _{-C0_6alkylN} ^{( Rk} )(C(O)NR ^f R ^g ) and -C _0-6 alkylN(R ^k )(S(O) _v R ^j ) wherein the alkyl is unsubstituted or substituted with one to three substituents selected from the group consisting of halogen, OH, -OC _1-3 alkyl, -C _1-3 alkyl, -CO ₂ C _1-3 alkyl, -C(O)NH ₂ , -C _0-6 alkylNH ₂ and -C _0-6 alkylNH(C _1-3 alkyl).

In another embodiment of the present invention, each ^{Ra is} independently selected from the group consisting of halogen, _-C1-6alkyl , _-C0-6alkyl - _OC1-6alkyl , _-C0-6alkyl -OH and _{-C0-6alkylNRkRl} , wherein the alkyl is _{unsubstituted} or substituted with ^one to three substituents selected from the group consisting of halogen, OH, _{-OC1-3alkyl , -C1-3alkyl ,} ^{-CO2C1-3alkyl} , -C(O) _NH2 , _{-C0-6alkylNH2} and _-C0-6alkylNH ( _C1-3alkyl ). In a class of this embodiment, each Ra ^is independently selected from the group consisting of halogen, _-C1-6alkyl , _-C0-6alkyl - _{OC1-6alkyl , -C0-6alkyl} -OH and _{-C0-6alkylNRkRl} , wherein alkyl is unsubstituted or substituted ^with one to three substituents selected from halogen, OH, ^-OC1-3alkyl and _-C1-3alkyl . In another class of this embodiment, each Ra ^is independently selected from the group consisting of F, _-CH3 , _{-OCH3 , -CH2OCH3} , -( _CH2 ) _2OCH3 , _{-OH ,} -CH2OH, -( _CH2 ) _2OH , -( _CH2 ) _3OH , -CH ₍ OH ₎ CH2OH, -CH2CH(OH) _CH2OH , _{-NH2 , -CH2NH2, -(CH2)2NH2, -C(CH3)2NH2 , -(CH2)3NH2 , -NH ( CH3 ) , -CH2NH ( CH3 ) , and -CH2CH} (OH) _{CH2NH2 .}

In another embodiment of the present invention, each ^Ra is halogen. In a class of this embodiment, each ^Ra is F.

In another embodiment of the present invention, each Ra ^is independently selected from the group consisting of: _-C0-6alkyl - _OC1-6alkyl , wherein alkyl is unsubstituted or substituted with one to three substituents selected from: halogen, OH and _-C1-3alkyl . In a class of this embodiment, each Ra ^is independently selected from the group consisting of _{: -OCH3} , _-CH2OCH3 and -( _CH2 ) _{2OCH3 .}

In another embodiment of the present invention, each Ra ^is independently selected from the group consisting of -C _1-6 alkyl, -C _0-6 alkyl-OH and -C _0-6 alkylNR ^k R ^l , wherein alkyl is unsubstituted or substituted with one to three substituents selected from halogen, OH, -OC _1-3 alkyl, -C _1-3 alkyl, -CO ₂ C _1-3 alkyl, -C (O) NH ₂ , -C _0-6 alkylNH ₂ and -C _0-6 alkylNH (C _1-3 alkyl). In a class of this embodiment, each Ra ^is independently selected from the group consisting of -C _1-6 alkyl, -C 0-6 alkyl-OH and -C _0-6 alkylNR ^k R ^l , wherein alkyl is unsubstituted or substituted with one to three substituents selected from halogen, _{OH and -C 1-3 alkyl} . In another class of this embodiment, each Ra ^is independently selected from the group consisting of: _-CH3 , -OH, _-CH2OH , -( _CH2 ) _{2OH ,} -(CH2 _{) 3OH ,} -CH(OH)CH2OH, _-CH2CH (OH) _CH2OH , -NH2 _, -CH2NH2, _- ( _{CH2)2NH2 ,} -C( _{CH3 ) 2NH2} , -( _CH2 ) _3NH2 , -NH( _{CH3 )} , _{-CH2NH ( CH3} ), and _-CH2CH (OH) _{CH2NH2 .} In another class of this embodiment, each Ra ^is independently selected from the group consisting of: _-CH3 , -OH, _-NH2 , _{-CH2NH2 ,} and _-CH2CH (OH) _{CH2NH2 .}

In another embodiment of the invention, each Ra ^is independently selected from the group consisting of _C1-6 alkyl, wherein alkyl is unsubstituted or substituted with one to three substituents selected from halogen, OH, _-OC1-3 alkyl and _-C1-3 alkyl. In a class of this embodiment, each ^Ra is _-CH3 .

In another embodiment of the present invention, each ^Ra is _-C0-6alkyl -OH, wherein the alkyl is unsubstituted or substituted with one to three substituents selected from the group consisting of halogen, OH, _-OC1-3alkyl and _-C1-3alkyl . In a class of this embodiment, each Ra ^is independently selected from the group consisting of -OH, _-CH2OH , -( _CH2 ) _2OH , -( _CH2 ) _3OH , -CH(OH) _CH2OH and _-CH2CH (OH) _CH2OH .

In another embodiment of the invention, each ^Ra is _{-C0-6alkylNRkRl} , wherein alkyl is unsubstituted or substituted with one to three substituents selected from the group consisting ^of halogen, OH, _-OC1-3alkyl , and _-C1-3alkyl . In a class of this embodiment, each Ra ^{is independently} selected from the group consisting of _-NH2 , _-CH2NH2 , _{-(CH2)2NH2, -C(CH3)2NH2, -(CH2)3NH2 , -NH ( CH3 ) , -CH2NH ( CH3 ) , and -CH2CH} (OH) _{CH2NH2 .}

In another embodiment of the present invention, each R ^b is independently selected from the group consisting of hydrogen, -C _1-6 alkyl, -C _0-6 alkyl-OC _1-6 alkyl, -C _0-6 alkyl-OH, -C _0-6 alkyl-S(O) _uR ^d , -C _1-6 alkyl-C(ON( ^Re ) ₂ , -C _1-6 alkylN( ^Re )C(O) ^Re , -C _0-6 alkyl-N( ^Re ) ₂ and halogen, wherein the alkyl is unsubstituted or substituted with one to three halogens, and wherein two R ^b substituents together with the atoms to which they are attached can cyclize to form a monocyclic C _3-6 cycloalkyl or a monocyclic C _2-6 cycloheteroalkyl ring.

In another embodiment of the present invention, each R ^b is independently selected from the group consisting of hydrogen, -C _1-6 alkyl, -C _0-6 alkyl-OC _1-6 alkyl, -C _0-6 alkyl-OH and halogen, wherein the alkyl is unsubstituted or substituted with one to three halogens, and wherein two R ^b substituents together with the atoms to which they are attached can cyclize to form a monocyclic C _3-6 cycloalkyl or a monocyclic C _2-6 cycloheteroalkyl ring.

In another embodiment of the present invention, each R ^b is independently selected from the group consisting of hydrogen, -C _1-6 alkyl, -C _0-6 alkyl-OC _1-6 alkyl, -C _0-6 alkyl-OH and halogen, wherein the alkyl is unsubstituted or substituted with one to three halogens, and wherein two R ^b substituents together with the atoms to which they are attached can cyclize to form a monocyclic C _3-6 cycloalkyl or a monocyclic C _2-6 cycloheteroalkyl ring.

In another embodiment of the present invention, each R ^b is independently selected from the group consisting of hydrogen, -C _1-6 alkyl, -C _0-6 alkyl-OC _1-6 alkyl, -C _0-6 alkyl-OH and halogen, wherein the alkyl is unsubstituted or substituted with one to three halogens, and wherein two R ^b substituents together with the atoms to which they are attached can cyclize to form a monocyclic C _3-6 cycloalkyl or a monocyclic C _2-6 cycloheteroalkyl ring.

In another embodiment of the present invention, each R ^is independently selected from the group consisting of the following: hydrogen, C _1-6 alkyl and halogen, wherein alkyl is not substituted or replaced by one to three halogens, and wherein two R ^substituents can be cyclized to form 3 to 6 rings together with the atoms to which they are connected. In a class of the present embodiment, each R ^is independently selected from the group consisting of the following: hydrogen and-C _1-6 alkyl, wherein alkyl is not substituted or replaced by one to three halogens, and wherein two R ^substituents can be cyclized to form 3 to 6 rings together with the atoms to which they are connected. In another class of the present embodiment, each ^R is C _1-6 alkyl, wherein alkyl is not substituted or replaced by one to three halogens, and wherein two R ^substituents can be cyclized to form 3 to 6 rings together with the atoms to which they are connected. In another class of the present embodiment, each ^R is C _1-6 alkyl, wherein alkyl is not substituted or replaced by one to three halogens. In another class of the present embodiment, each ^R is hydrogen.

In another embodiment of the present invention, each R ^c is independently selected from the group consisting of hydrogen, -C _1-6 alkyl, -C _0-6 alkyl-OC _1-6 alkyl, -C _0-6 alkyl-OH, -C _0-6 alkyl-S(O) _v R ^f , -C _0-6 alkyl-S(O) _v N(R ^g ) ₂ , -C _1-6 alkylC(O)-N(R ^g ) ₂ , -C _1-6 alkylN(R ^g )C(O)R ^g , -C _0-6 alkyl-N(R ^g ) ₂ and halogen, wherein the alkyl group is unsubstituted or substituted with one to three halogens.

In another embodiment of the present invention, each R ^c is independently selected from the group consisting of hydrogen, -C _1-6 alkyl, -C _0-6 alkyl-OC _1-6 alkyl, -C _0-6 alkyl-OH and halogen, wherein alkyl is unsubstituted or substituted with one to three halogens.

In another embodiment of the present invention, each R ^c is independently selected from the group consisting of the following: hydrogen, -C _1-6 alkyl, -C _0-6 alkyl-OC _1-6 alkyl and halogen, wherein the alkyl is not substituted or substituted by one to three halogens. In a class of this embodiment, each R ^c is independently selected from the group consisting of the following: hydrogen, -C _1-6 alkyl, -OC _1-6 alkyl and halogen, wherein the alkyl is not substituted or substituted by one to three halogens.

In another embodiment of the present invention, each R ^c is independently selected from the group consisting of hydrogen, -C _1-6 alkyl and -C _0-6 alkyl-OC _1-6 alkyl, wherein the alkyl is unsubstituted or substituted with one to three halogens. In one class of this embodiment, each R ^c is independently selected from the group consisting of hydrogen, -C _1-6 alkyl and -OC _1-6 alkyl, wherein the alkyl is unsubstituted or substituted with one to three halogens. In another class of this embodiment, each R ^c is independently selected from the group consisting of hydrogen, -CH ₃ and -OCH ₃ .

In another embodiment of the present invention, each R ^c is independently selected from the group consisting of: C _1-6 alkyl and C _0-6 alkyl-OC _1-6 alkyl, wherein the alkyl is unsubstituted or substituted with one to three halogens. In a class of this embodiment, each R ^c is independently selected from the group consisting of: C _1-6 alkyl and -OC _1-6 alkyl, wherein the alkyl is unsubstituted or substituted with one to three halogens. In another class of this embodiment, each R ^c is independently selected from the group consisting of: -CH ₃ and -OCH ₃ .

In another embodiment of the invention, each R ^c is C _1-6 alkyl, wherein alkyl is unsubstituted or substituted with one to three halogens. In a class of this embodiment, each R ^c is -CH ₃ .

In another embodiment of the present invention, R ^is independently selected from the group consisting of: hydrogen and -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted by one to three halogens. In a class of the present embodiment, R ^is -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted by one to three halogens. In another class of the present embodiment, ^R is hydrogen.

In another embodiment of the present invention, Re ^is independently selected from the group consisting of hydrogen and -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted by one to three halogens. In one class of this embodiment, ^Re is -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted by one to three halogens. In another class of this embodiment, ^Re is hydrogen.

In another embodiment of the present invention, R ^is independently selected from the group consisting of: hydrogen and-C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted by one to three halogens. In a class of the present embodiment, R ^is -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted by one to three halogens. In another class of the present embodiment, ^R is hydrogen.

In another embodiment of the present invention, R ^is independently selected from the group consisting of hydrogen and -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted by one to three halogens. In one class of this embodiment, ^R is -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted by one to three halogens. In another class of this embodiment, ^R is hydrogen.

In another embodiment of the present invention, R ^is independently selected from the group consisting of hydrogen and -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted by one to three halogens. In one class of this embodiment, R ^is -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted by one to three halogens. In another class of this embodiment, ^R is hydrogen.

In another embodiment of the invention, each R ⁱ is -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted with one to three halogens. In a class of this embodiment, each R ⁱ is -C _1-6 alkyl. In another class of this embodiment, each R ⁱ is -CH ₃ .

In another embodiment of the present invention, R ^is independently selected from the group consisting of the following: hydrogen, OH and-C _1-6 alkyl, wherein each alkyl is not substituted or replaced by one to three halogens. In a class of the present embodiment, R ^is independently selected from the group consisting of the following: hydrogen and-C _1-6 alkyl, wherein each alkyl is not substituted or replaced by one to three halogens. In another class of the present embodiment, ^R is hydrogen or OH. In another class of the present embodiment, ^R is OH. In another class of the present embodiment, ^R is hydrogen. In another class of the present embodiment, R ^is -C _1-6 alkyl, wherein each alkyl is not substituted or replaced by one to three halogens.

In another embodiment of the present invention, R ^is independently selected from the group consisting of hydrogen and -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted with one to three halogens. In one class of this embodiment, ^R is -C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted with one to three halogens. In another class of this embodiment, ^R is hydrogen.

In another embodiment of the present invention, ^R1 is independently selected from the group consisting of: hydrogen and _-C1-6 alkyl, wherein each alkyl is unsubstituted or substituted by one to three halogens. In one class of this embodiment, ^R1 is _-C1-6 alkyl, wherein each alkyl is unsubstituted or substituted by one to three halogens. In another class of this embodiment, ^R1 is hydrogen.

In another embodiment of the invention, each r is independently 0, 1 or 2. In one class of this embodiment, r is 0 or 1. In another class of this embodiment, r is 1 or 2. In another class of this embodiment, r is 0 or 2. In another class of this embodiment, r is 0. In another class of this embodiment, r is 1. In another class of this embodiment, r is 2.

In another embodiment of the invention, each s is independently 0, 1, 2, 3, 4, or 5. In one class of this embodiment, each s is independently 0, 1, 2, 3, or 4. In another class of this embodiment, each s is independently 0, 1, 2, or 3. In another class of this embodiment, each s is independently 1, 2, or 3. In another class of this embodiment, each s is independently 1 or 3. In another class of this embodiment, s is 0 or 1. In another class of this embodiment, s is 1 or 2. In another class of this embodiment, s is 0. In another class of this embodiment, s is 1. In another class of this embodiment, s is 2. In another class of this embodiment, s is 3. In another class of this embodiment, s is 4. In another class of this embodiment, s is 5.

In another embodiment of the invention, each t is independently 0, 1, 2, or 3. In one class of this embodiment, t is 0, 1, or 2. In another class of this embodiment, t is 0 or 1. In another class of this embodiment, t is 1 or 2. In another class of this embodiment, t is 0 or 2. In another class of this embodiment, t is 0. In another class of this embodiment, t is 1. In another class of this embodiment, t is 2. In another class of this embodiment, t is 3.

In another embodiment of the invention, each u is independently 0, 1 or 2. In one class of this embodiment, u is 0 or 1. In another class of this embodiment, u is 1 or 2. In another class of this embodiment, u is 0 or 2. In another class of this embodiment, u is 0. In another class of this embodiment, u is 1. In another class of this embodiment, u is 2.

In another embodiment of the invention, each v is independently 0, 1 or 2. In one class of this embodiment, v is 0 or 1. In another class of this embodiment, v is 1 or 2. In another class of this embodiment, v is 0 or 2. In another class of this embodiment, v is 0. In another class of this embodiment, v is 1. In another class of this embodiment, v is 2.

In another embodiment of the present invention, the present invention is directed to compounds of formula Ia:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the present invention is directed to compounds of formula Ib:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the present invention is directed to compounds of formula Ic:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the present invention is directed to compounds of formula Id:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the present invention is directed to compounds of formula Ie:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the present invention is directed to compounds of formula If:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the present invention is directed to compounds of formula Ig:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the present invention is directed to compounds of formula Ih:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the present invention is directed to compounds of formula Ii:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the present invention is directed to compounds of formula Ij:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the present invention is directed to compounds of formula Ik:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the present invention is directed to compounds of formula II:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the present invention is directed to compounds of formula Im:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the present invention relates to compounds of formula In:

or a pharmaceutically acceptable salt thereof.

Compounds of structural formula I include compounds of structural formulas Ia, Ib, Ic, Id, Ie, If, Ig, Ih, Ii, Ij, Ik, Il, Im and In and pharmaceutically acceptable salts, hydrates and solvates thereof.

Another embodiment of the present invention is directed to compounds of formula I, wherein:

T is CH;

U is CH;

V is CH;

X is CH ₂ ;

Y is O or CH ₂ ;

Z is O or CH ₂ ;

W is a bond or O;

Q is CR ⁸ ;

^R1 is selected from the group consisting of:

1) -C _3-9 cycloalkyl,

2) -C _2-8 cycloheteroalkyl,

3) aryl, and

4) heteroaryl,

wherein cycloalkyl, cycloheteroalkyl, aryl and heteroaryl are unsubstituted or substituted with one to five substituents selected from ^Ra ;

^R2 is hydrogen;

^R3 is hydrogen;

^R4 is selected from the group consisting of:

1) C _1-3 alkyl, and

2) _C3 cycloalkyl,

wherein alkyl and cycloalkyl are unsubstituted or substituted with one to three substituents selected from the group consisting of halogen and OC _1-3 alkyl;

R ⁵ is -CO ₂ H or tetrazole;

^R6 is hydrogen;

^R7 is hydrogen;

^R8 is hydrogen;

R ⁹ is C _1-6 alkyl;

R ¹⁰ is C _1-6 alkyl; and

^Ra , ^Rb , ^Rc , Rd, ^Re , ^Rf , ^Rg , ^Rh , ^Ri , ^Rj , ^Rk , ^Rl , ^r , s, t, u and v are as defined above;

or a pharmaceutically acceptable salt thereof.

Another embodiment of the present invention is directed to compounds of formula I, wherein:

T is CH;

U is CH;

V is CH;

X is CH ₂ ;

Y is CH ₂ ;

Z is O;

W is O;

Q is CR ⁸ ;

^R1 is selected from the group consisting of:

1) -C _3-9 cycloalkyl,

2) -C _2-8 cycloheteroalkyl, and

3) aryl,

wherein cycloalkyl, cycloheteroalkyl and aryl are unsubstituted or substituted with one to five substituents selected from ^Ra ;

^R2 is hydrogen;

^R3 is hydrogen;

^R4 is _C1-3 alkyl;

R ⁵ is -CO ₂ H;

^R6 is hydrogen;

^R7 is hydrogen;

^R8 is hydrogen;

R ⁹ is C _1-6 alkyl;

R ¹⁰ is C _1-6 alkyl; and

^Ra , ^Rb , ^Rc , Rd, ^Re , ^Rf , ^Rg , ^Rh , ^Ri , ^Rj , ^Rk , ^Rl , ^r , s, t, u and v are as defined above;

or a pharmaceutically acceptable salt thereof.

Another embodiment of the present invention is directed to compounds of formula I, wherein:

T is CH;

U is CH;

V is CH;

X is CH ₂ ;

Y is CH ₂ ;

Z is O;

W is O;

Q is CR ⁸ ;

^R1 is selected from the group consisting of:

1) -C _3-9 cycloalkyl, and

2) -C _2-8 cycloheteroalkyl,

wherein cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with one to five substituents selected from ^Ra ;

^R2 is hydrogen;

^R3 is hydrogen;

^R4 is _C1-3 alkyl;

R ⁵ is -CO ₂ H;

^R6 is hydrogen;

^R7 is hydrogen;

^R8 is hydrogen;

R ⁹ is C _1-6 alkyl;

R ¹⁰ is C _1-6 alkyl; and

^Ra , ^Rb , ^Rc , Rd, ^Re , ^Rf , ^Rg , ^Rh , ^Ri , ^Rj , ^Rk , ^Rl , ^r , s, t, u and v are as defined above;

or a pharmaceutically acceptable salt thereof.

Illustrative but non-limiting examples of compounds of the present invention are as follows:

1)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((S)-pyrrolidin-3-yl)carbamimidoyl)-chroman-2-yl)propanoic acid;

2)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((R)-pyrrolidin-3-yl)-carbamimidoyl)-chroman-2-yl)propanoic acid;

3)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3S,5R)-5-(hydroxymethyl)-pyrrolidin-3-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

4)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3R,5R)-5-(hydroxymethyl)pyrrolidin-3-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

5)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((S)-azepan-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

6)(S)-2-((R)-6-(N-((1s,4S)-4-aminocyclohexyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)-amino)-2-oxo-ethylidene)amino)oxy)propanoic acid;

7)(S)-2-((R)-6-(N-((1s,3S)-3-aminocyclobutyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)propanoic acid;

8)(S)-2-((R)-6-(N-((1r,3R)-3-aminocyclobutyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)propanoic acid;

9)(S)-2-((R)-6-(N-(3-(aminomethyl)bicyclo[1.1.1]pentan-1-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

10) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((R)-azepan-3-yl)carbamimidoyl)-chroman-2-yl)propanoic acid;

11)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((S)-azepan-3-yl)carbamimidoyl)-chroman-2-yl)propanoic acid;

12)(S)-2-((R)-6-(N-(1-(aminomethyl)-2-oxabicyclo[2.1.1]hexan-4-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

13)(S)-2-((R)-6-(N-(2-azaspiro[3.5]nonan-7-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)propanoic acid;

14)(S)-2-((R)-6-(N-(2-azaspiro[3.3]hept-6-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)propanoic acid;

15)(S)-2-((R)-6-(N-(5-aminobicyclo[3.1.1]hept-1-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

16) (2S)-2-((2R)-6-(N-((1S,5R)-3-azabicyclo[3.2.0]hept-6-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

17)(S)-2-((R)-6-(N-((4R,6s)-1-azaspiro[3.3]hept-6-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxo-ethylidene)amino)oxy)propanoic acid;

18)(S)-2-((R)-6-(N-((4S,6r)-1-azaspiro[3.3]hept-6-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxo-ethylidene)amino)oxy)propanoic acid;

19)(S)-2-((R)-6-(N-((2s,4R)-6-azaspiro[3.5]nonan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

20)(S)-2-((R)-6-(N-((2r,4S)-6-azaspiro[3.5]nonan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

21)(S)-2-((R)-6-(N-(7-azaspiro[3.5]nonan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

22)(S)-2-((R)-6-(N-((2r,4S)-6-azaspiro[3.4]octan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

23)(S)-2-((R)-6-(N-((2s,4R)-6-azaspiro[3.4]octan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

24)(S)-2-((R)-6-(N-((1S,2R,5R,6R)-5-aminobicyclo[4.1.0]hept-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

25)(S)-2-((R)-6-(N-((1R,2R,5S,6S)-5-aminobicyclo[4.1.0]hept-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

26)(S)-2-((R)-6-(N-((1S,2S,5R,6R)-5-aminobicyclo[4.1.0]hept-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

27)(S)-2-((R)-6-(N-((1R,2S,5S,6S)-5-aminobicyclo[4.1.0]hept-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

28)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-(piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

29)(S)-2-((R)-6-(N-(1-((R)-3-amino-2-hydroxypropyl)piperidin-4-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

30)(S)-2-((R)-6-(N-(1-((S)-3-amino-2-hydroxypropyl)piperidin-4-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

31)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((R)-azepan-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

32)(S)-2-((R)-6-(N-((1r,4R)-4-aminocyclohexyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)propanoic acid;

33)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3R,5S)-5-(hydroxymethyl)pyrrolidin-3-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

34)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1r,4R)-4-(methylamino)cyclohexyl)-carbamimidoyl)chroman-2-yl)propanoic acid;

35)(S)-2-((R)-6-(N-(4-aminobicyclo[2.2.2]octan-1-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

36)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-(azetidin-3-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

37)(S)-2-((R)-6-(N-((1R,5S,6s)-3-azabicyclo[3.1.0]hexan-6-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

38)(S)-2-((R)-6-(N-(4-(aminomethyl)phenyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

39)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((R)-piperidin-3-yl)carbamimidoyl)-chroman-2-yl)propanoic acid;

40)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((S)-piperidin-3-yl)carbamimidoyl)-chroman-2-yl)propanoic acid;

41)(S)-2-((R)-6-(N-((1s,4S)-4-(aminomethyl)cyclohexyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

42)(S)-2-((R)-6-(N-((1r,4R)-4-(aminomethyl)cyclohexyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

43)(S)-2-((R)-6-(N-((2s,4R)-6-azaspiro[3.4]octan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

44)(S)-2-((R)-6-(N-((2r,4S)-6-azaspiro[3.4]octan-2-yl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

45)(S)-2-((R)-6-(N-((1R,3S)-3-aminocyclopentyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

46)(S)-2-((R)-6-(N-((1S,3R)-3-aminocyclopentyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

47)(S)-2-((R)-6-(N-((1S,3S)-3-aminocyclopentyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

48)(S)-2-((R)-6-(N-((1R,3R)-3-aminocyclopentyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

49)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((S)-3,3-dimethylpiperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

50)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((R)-3,3-dimethylpiperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

51)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3R,4S)-3-(hydroxymethyl)-piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

52)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3S,4R)-3-(hydroxymethyl)-piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

53)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((2S,4S)-2-(hydroxymethyl)-piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

54)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((2R,4R)-2-(hydroxymethyl)-piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

55)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((2R,4R)-2-methylpiperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

56)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((2S,4S)-2-methylpiperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

57)(S)-2-((R)-6-(N-((1r,4R)-4-amino-4-methylcyclohexyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

58)(S)-2-((R)-6-(N-((1s,4S)-4-amino-4-methylcyclohexyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

59)(S)-2-((R)-6-(N-((1s,4S)-4-(aminomethyl)-4-hydroxycyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

60)(S)-2-((R)-6-(N-((1r,4R)-4-(aminomethyl)-4-hydroxycyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

61)(S)-2-((R)-6-(N-((2R,4r,6R)-6-aminospiro[3.3]hept-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

62)(S)-2-((R)-6-(N-((2S,4s,6S)-6-aminospiro[3.3]hept-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

63)(S)-2-((R)-6-(N-((1s,4S)-4-amino-4-(2-methoxyethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

64)(S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(2-methoxyethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

65)(S)-2-((R)-6-(N-((1s,4S)-4-amino-4-(2-hydroxyethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

66)(S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(2-hydroxyethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

67)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-(trans-3-(methylamino)cyclobutyl)-carbamimidoyl)chroman-2-yl)propanoic acid;

68)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-(cis-3-(methylamino)cyclobutyl)-carbamimidoyl)chroman-2-yl)propanoic acid;

69)(S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(hydroxymethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

70)(S)-2-((R)-6-(N-((1s,4S)-4-amino-4-(hydroxymethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

71)(S)-2-((R)-6-(N-((1r,4R)-4-amino-1-methylcyclohexyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

72)(S)-2-((R)-6-(N-((1s,4S)-4-amino-1-methylcyclohexyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

73)(S)-2-((R)-6-(N-((1s,4S)-4-(aminomethyl)-4-methoxycyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

74)(S)-2-((R)-6-(N-((1r,3R)-3-amino-3-methylcyclobutyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

75)(S)-2-((R)-6-(N-((1s,3S)-3-amino-3-methylcyclobutyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

76)(S)-2-((R)-6-(N-((1R,5S,8s)-3-azabicyclo[3.2.1]octan-8-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

77)(S)-2-((R)-6-(N-((1R,5S,8r)-3-azabicyclo[3.2.1]octan-8-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

78)(S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)-3-(hydroxymethyl)cyclobutyl)-carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)-oxy)propanoic acid;

79)(S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)-3-(hydroxymethyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

80)(S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)-3-hydroxycyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

81)(S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)-3-hydroxycyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

82)(S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)-3-methoxycyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

83)(S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)-3-methoxycyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

84)(S)-2-((R)-6-(N-((1r,3R)-3-amino-1-methylcyclobutyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

85)(S)-2-((R)-6-(N-((1s,3S)-3-amino-1-methylcyclobutyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

86)(S)-2-((R)-6-(N-((1s,3S)-3-amino-3-(2-hydroxyethyl)cyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

87)(S)-2-((R)-6-(N-((1r,3R)-3-amino-3-(2-hydroxyethyl)cyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

88)(S)-2-((R)-6-(N-((1r,3R)-3-amino-3-(hydroxymethyl)cyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

89)(S)-2-((R)-6-(N-((1s,3S)-3-amino-3-(hydroxymethyl)cyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

90)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1r,3R)-3-(hydroxymethyl)-3-(methylamino)cyclobutyl)amidino)chroman-2-yl)propanoic acid;

91)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1s,3S)-3-(hydroxymethyl)-3-(methylamino)cyclobutyl)amidino)chroman-2-yl)propanoic acid;

92)(S)-2-((R)-6-(N-((1r,3R)-3-amino-3-(2-methoxyethyl)cyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

93)(S)-2-((R)-6-(N-((1s,3S)-3-amino-3-(2-methoxyethyl)cyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

94)(S)-2-((R)-6-(N-((1S,3R)-3-amino-3-((S)-2,3-dihydroxypropyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

95)(S)-2-((R)-6-(N-((1R,3R)-3-amino-3-((R)-2,3-dihydroxypropyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

96)(S)-2-((R)-6-(N-((1R,3S)-3-amino-3-((S)-2,3-dihydroxypropyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

97)(S)-2-((R)-6-(N-((1S,3S)-3-amino-3-((R)-2,3-dihydroxypropyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

98)(S)-2-((R)-6-(N-((1S,3R)-3-amino-3-((S)-1,2-dihydroxyethyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

99)(S)-2-((R)-6-(N-((1R,3R)-3-amino-3-((R)-1,2-dihydroxyethyl)cyclobutyl)-carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

100)(S)-2-((R)-6-(N-((1S,3S)-3-amino-3-((R)-1,2-dihydroxyethyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

101)(S)-2-((R)-6-(N-((1R,3S)-3-amino-3-((S)-1,2-dihydroxyethyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

102)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1s,4S)-4-((methylamino)methyl)-cyclohexyl)amidino)chroman-2-yl)propanoic acid;

103)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1r,4R)-4-((methylamino)methyl)cyclohexyl)amidino)chroman-2-yl)propanoic acid;

104)(S)-2-((R)-6-(N-((1R,4S)-4-aminocycloheptyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

105)(S)-2-((R)-6-(N-((1R,4R)-4-aminocycloheptyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

106)(S)-2-((R)-6-(N-((1S,4S)-4-aminocycloheptyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

107)(S)-2-((R)-6-(N-((1S,4R)-4-aminocycloheptyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

108)(S)-2-((R)-6-(N-((1R,3R)-3-aminocyclohexyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

109)(S)-2-((R)-6-(N-((1S,3S)-3-aminocyclohexyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

110)(S)-2-((R)-6-(N-((1R,3S)-3-aminocyclohexyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

111)(S)-2-((R)-6-(N-((1S,3R)-3-aminocyclohexyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

112)(S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)cyclobutyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

113)(S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)cyclobutyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

114)(S)-2-((R)-6-(N-((1S,3S)-3-amino-2,2-dimethylcyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

115)(S)-2-((R)-6-(N-((2S,4s,7S)-2-aminospiro[3.5]nonan-7-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

116)(S)-2-((R)-6-(N-((2R,4r,7R)-2-aminospiro[3.5]nonan-7-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

117)(S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)-3-methylcyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

118)(S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)-3-methylcyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

119)(S)-2-((R)-6-(N-(6-(Aminomethyl)-6-fluorospiro[3.3]hept-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

120)(S)-2-((R)-6-(N-((1R,3S)-3-(aminomethyl)-2,2-dimethylcyclobutyl)-carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

121) (2S)-2-((2R)-6-(N-(6-(Aminomethyl)spiro[3.3]hept-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

122) (2S)-2-((2R)-6-(N-((1S)-1-aminospiro[2.3]hexan-5-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

123) (2S)-2-((2R)-6-(N-((1R)-1-aminospiro[2.3]hexan-5-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

124)(S)-2-((R)-6-(N-((1s,3S)-3-aminocyclobutyl)carbamimidyl)-5-(methoxymethyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

125)(S)-2-((R)-6-(N-((1s,3S)-3-aminocyclobutyl)carbamimidyl)-7-(methoxymethyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

126)(S)-2-((R)-6-(N-((1s,4S)-4-amino-1-(methoxymethyl)cyclohexyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

127)(S)-2-((R)-6-(N-((1r,4R)-4-amino-1-(methoxymethyl)cyclohexyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

128)(S)-2-((R)-6-(N-((1s,4S)-4-amino-4-(methoxymethyl)cyclohexyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

129)(S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(methoxymethyl)cyclohexyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

130)(S)-2-((R)-6-(N-((1s,4S)-4-(aminomethyl)-1-methylcyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

131)(S)-2-((R)-6-(N-((1r,4R)-4-(aminomethyl)-1-methylcyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

132)(S)-2-((R)-6-(N-((1s,4S)-4-(2-aminopropan-2-yl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

133)(S)-2-((R)-6-(N-((1r,4R)-4-(2-aminopropan-2-yl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

134)(S)-2-((R)-6-(N-((1s,3S)-3-aminocyclobutyl)carbamimidyl)-7-methylchroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

135)(S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(hydroxymethyl)-1-methylcyclohexyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

136)(S)-2-((R)-6-(N-((1R,3r,5S)-8-azabicyclo[3.2.1]octan-3-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

137)(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3S,5S)-5-(hydroxymethyl)pyrrolidin-3-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

138) (S)-2-((R)-6-(N-(1-(2-aminoethyl)cyclopropyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

139)(S)-2-((R)-6-(N-(1-(3-aminopropyl)cyclopropyl)amidinoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid; and

140)(S)-2-((R)-6-(N-(1-(2-aminoethyl)cyclobutyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

or a pharmaceutically acceptable salt thereof.

Illustrative but non-limiting examples of compounds of the present invention are as follows:

or its diastereomers, and pharmaceutically acceptable salts thereof.

Other embodiments of the present invention include:

(a) A pharmaceutical composition comprising an effective amount of a compound of formula (I) as defined herein or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

(b) The pharmaceutical composition according to (a), further comprising a second compound, wherein the second compound is a β-lactamase inhibitor.

(c) The pharmaceutical composition according to (b), wherein the second compound is selected from the group consisting of relebactam, tazobactam, clavulanic acid, sulbactam, avibactam, taniborbactam, nacubactam, vaborbactam, zidebactam, durlobactam, enmetazobactam and QPX7728 (xeruborbactam) or a pharmaceutically acceptable salt thereof.

(d) A pharmaceutical composition comprising (i) a compound of formula (I) or a pharmaceutically acceptable salt thereof, and (ii) a second compound, wherein the second compound is a β-lactamase inhibitor compound, wherein the compound of formula (I) and the second compound are each used in an amount such that the combination is effective for treating or preventing bacterial infection.

(e) The composition according to (d), wherein the second compound is selected from the group consisting of relebactam, tazobactam, clavulanic acid, sulbactam, avibactam, tanibocactam, nakubactam, vaborbactam, zidabactam, dulobactam, enmetabactam and QPX7728 (ciborbactam) or a pharmaceutically acceptable salt thereof.

(f) A method of treating a bacterial infection in a subject, comprising administering to a subject in need of such treatment an effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof.

(g) A method for preventing and/or treating bacterial infection, which comprises administering to a subject in need of such treatment a pharmaceutical composition comprising an effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier.

(h) A method of treating a bacterial infection comprising administering to a subject in need of such treatment a therapeutically effective amount of the composition of (a), (b), (c), (d) or (e).

(i) The method for treating a bacterial infection according to (f), (g) or (h), wherein the bacterial infection is caused by Gram-negative bacteria.

(j) The method for treating a bacterial infection according to (f), (g), (h) or (i), wherein the bacterial infection is caused by Pseudomonas aeruginosa or Acinetobacter baumannii.

The present invention also includes a compound of formula (I) or a pharmaceutically acceptable salt thereof, which is (i) used to treat bacterial infection, (ii) used as a drug for treating bacterial infection, or (iii) used to prepare (or manufacture) a drug for treating bacterial infection, including infection with multidrug-resistant strains. In these uses, the compounds of the present invention may be optionally used in combination with one or more second therapeutic agents, including relebactam, tazobactam, clavulanic acid, sulbactam, avibactam, tanibocactam, nakubactam, faborbactam, zidabactam, dulobactam, enmetazobactam and QPX7728 (ciborbactam) or a pharmaceutically acceptable salt thereof.

Other embodiments of the present invention include the pharmaceutical compositions, combinations and methods described in (a)-(j) above and the uses described in the previous paragraph, wherein the compounds of the present invention used herein are compounds in one of the above embodiments, sub-embodiments, categories or subcategories. In these embodiments, the compound can optionally be used in the form of a pharmaceutically acceptable salt.

In the embodiments of compounds and salts provided above, it should be understood that each embodiment can be combined with one or more other embodiments, as long as this combination provides a stable compound or salt and is consistent with the description of the embodiment. It should also be further understood that the embodiments of the compositions and methods provided above (a) to (j) should be understood to include all embodiments of compounds and/or salts, including embodiments resulting from combinations of embodiments.

Other embodiments of the present invention include each of the pharmaceutical compositions, combinations, methods and uses described in the preceding paragraphs, wherein the compounds of the present invention or their salts used herein are substantially pure. For a pharmaceutical composition comprising a compound of formula (I) or its salt and a pharmaceutically acceptable carrier and optionally one or more excipients, it should be understood that the term "substantially pure" refers to the compound of formula (I) or its salt itself; i.e., the purity of the active ingredient in the composition.

Definitions and Abbreviations

The terms used herein have their ordinary meanings, and the meaning of the terms is independent at each occurrence. Nevertheless, unless otherwise stated, the following definitions apply to the entire specification and claims. Chemical names, common names, and chemical structures are used interchangeably to describe the same structure. If a compound uses both a chemical structure and a chemical name, and there is ambiguity between the structure and the name, the structure is dominant. Unless otherwise stated, these definitions apply regardless of whether a term is used alone or in combination with other terms. Therefore, the definition of "alkyl" applies to the "alkyl" part of "alkyl" as well as "hydroxyalkyl", "haloalkyl", "-O-alkyl", etc.

Unless otherwise indicated, the following terms used herein and in this disclosure shall be understood to have the following meanings:

The term "β-lactamase inhibitor" refers to a compound capable of inhibiting the enzymatic activity of a β-lactamase. As used herein, inhibition of β-lactamase activity refers to inhibition of the activity of class A, class C and/or class D β-lactamases. For antimicrobial applications, inhibition of a 50% inhibitory concentration is preferably achieved at or below about 100 micrograms/mL, or at or below about 50 micrograms/mL, or at or below about 25 micrograms/mL. The terms "class A", "class B", "class C" and "class D" β-lactamases are understood by those skilled in the art and are described in S.G.Waley, β-lactamase: mechanisms of action, in The Chemistry of β-Lactams, M.I.Page, Ed.; Chapman and Hall, London, (1992) 198-228.

The term "metallo-β-lactamase" refers to a metalloprotein that is capable of inactivating β-lactam antibiotics. β-lactamases can be enzymes that catalyze the hydrolysis of the β-lactam ring of β-lactam antibiotics. Of interest herein are microbial metallo-β-lactamases. Metallo-β-lactamases can be, for example, zinc metallo-β-lactamases. β-lactamases of interest include, for example, those disclosed in S.G.Waley, β-lactamase: mechanisms of action, in The Chemistry of β-Lactams, M.I.Page, Ed.; Chapman and Hall, London, (1992) 198-228. β-lactamases of particular interest herein include metallo-β-lactamases of Escherichia coli (e.g., New Delhi metallo-β-lactamase, NDM), metallo-β-lactamases of Serratia marcescens (e.g., IMP), and metallo-β-lactamases of Klebsiella (e.g., metallo-β-lactamases encoded by Verona integron, VIM). Other metallo-β-lactamases of interest herein include SPM-, GIM-, SIM-, KHM-, AIM-, DIM-, SMB-, TMB-, and FIM-type enzymes.

The term "antibiotic" refers to a compound or composition that reduces the viability of a microorganism or inhibits the growth or reproduction of a microorganism. The phrase "inhibits growth or proliferation" refers to increasing the generation time (i.e., the time required for bacterial cell division or population doubling) by at least about 2 times. Preferred antibiotics are those that can increase the generation time by at least about 10 times or more (e.g., at least about 100 times or even indefinitely, such as complete cell death). As used in the present disclosure, antibiotics are further intended to include antimicrobial agents, bacteriostats, or bactericides. Examples of antibiotics include penicillins, cephalosporins, and carbapenems.

The term "β-lactam antibiotic" refers to a compound containing a β-lactam functional group having antibiotic properties. Non-limiting examples of β-lactam antibiotics include penicillins, cephalosporins, penems, carbapenems and monobactams.

When modifying the amount of a substance or composition (e.g., kg, L, or equivalents) or the value of a physical property or the value of a parameter characterizing a protocol step (e.g., the temperature at which a method step is performed), etc., the term "about" refers to changes in the numerical quantity that may occur, for example, by typical measurements, handling, and sampling procedures involved in the preparation, characterization, and/or use of the substance or composition; by inadvertent errors in these procedures; by differences in the manufacture, source, or purity of the ingredients used to make or use the composition or perform the procedure; etc. In certain embodiments, "about" may refer to changes of ±0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 2.0, 3.0, 4.0, or 5.0 of the appropriate unit. In certain embodiments, "about" may refer to changes of ±1%, 2%, 3%, 4%, 5%, 10%, or 20%.

Another embodiment of the present invention is a compound of formula (I) or a pharmaceutically acceptable salt thereof as defined initially or as defined in any of the aforementioned embodiments, sub-embodiments, aspects, categories or subclasses, wherein the compound or its salt is in substantially pure form. As used herein, "substantially pure" appropriately refers to at least about 60wt.%, typically at least about 70wt.%, preferably at least about 80wt.%, more preferably at least about 90wt.% (e.g., about 90wt.% to about 99wt.%), even more preferably at least about 95wt.% (e.g., about 95wt.% to about 99wt.%, or about 98wt.% to 100wt.%), most preferably at least about 99wt.% (e.g., 100wt.%) comprising a product of a compound of formula (I) or its salt (e.g., a product separated from a reaction mixture providing the compound or salt) consisting of the compound or its salt. The purity level of compounds and salts can be determined using standard analytical methods, such as thin layer chromatography, gel electrophoresis, high performance liquid chromatography and/or mass spectrometry. If more than one analytical method is employed and the methods provide experimentally significant differences in the purity levels determined, the method providing the highest purity level shall prevail. A 100% pure compound or salt is one that contains no detectable impurities as determined by standard analytical methods.

For compounds of the present invention having one or more asymmetric centers and which can exist as mixtures of stereoisomers, unless otherwise expressly stated, substantially pure compounds can be substantially pure mixtures of stereoisomers, or substantially pure single diastereomers or enantiomers. The present invention includes all stereoisomeric forms of compounds of formula (I). Unless specific stereochemistry is indicated, the present invention is intended to encompass all such isomeric forms of these compounds. Asymmetric centers present in compounds of formula (I) can have, independently of one another, (R) configuration or (S) configuration.

When the bond to a chiral carbon in a structural formula of the present invention is described as a straight line, it is understood that the (R) and (S) configurations of the chiral carbon and therefore enantiomers and mixtures thereof are all included in the formula. Similarly, when there is no chiral symbol for a chiral carbon in the name of a compound, it is understood that the (R) and (S) configurations of the chiral carbon and therefore individual enantiomers and mixtures thereof are all included in the name. The production of a specific stereoisomer or mixture thereof can be determined in the examples where such stereoisomer or mixture thereof is obtained, but this does not in any way limit the inclusion of all stereoisomers and mixtures thereof within the scope of the present invention.

The present invention includes all possible enantiomers and diastereomers and mixtures of all proportions of two or more stereoisomers, such as mixtures of enantiomers and/or diastereomers. Therefore, enantiomers are the subject of the present invention, which are enantiomerically pure forms, either left-handed enantiomers or right-handed enantiomers, racemates, or mixtures of two enantiomers in all proportions. In the case of cis/trans isomerism, the present invention includes mixtures of cis and trans forms and all proportions of these forms. If desired, the preparation of a single stereoisomer can be carried out by conventional methods (e.g., by chromatography or crystallization) to separate a mixture, using stereochemically uniform synthetic starting materials or by stereoselective synthesis. Optionally, derivatization can be carried out before stereoisomer separation. The separation of a stereoisomer mixture can be carried out in an intermediate step of the process of synthesizing a compound of formula (I) or on a final racemic product. Absolute stereochemistry can be determined by X-ray crystallography of a crystalline product or a crystalline intermediate, if desired, using a reagent containing a stereocenter of known configuration. When the compounds of the present invention are capable of tautomerization, all individual tautomers and mixtures thereof are included within the scope of the present invention. Unless a specific isomer, salt, solvate (including hydrate) or solvate salt of such racemate, enantiomer, diastereomer or tautomer is specified, the present invention includes all such isomers and salts, solvates (including hydrates) and solvate salts of such racemate, enantiomer, diastereomer and tautomer and mixtures thereof.

definition:

"Ac" is acetyl, ie, CH ₃ C(=O)-.

"Alkyl" refers to a saturated carbon chain, which may be straight or branched, or combinations thereof, unless the carbon chain is otherwise defined. Other groups with the prefix "alk", such as alkoxy and alkanoyl, may also be straight or branched, or combinations thereof, unless the carbon chain is otherwise defined. Examples of alkyl include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, and the like.

"Aryl" refers to a monocyclic, bicyclic or fused carbocyclic aromatic ring or ring system containing carbon atoms, wherein at least one ring is an aromatic ring. The term aryl also includes aryl groups as defined above, which are fused to an aryl, cycloalkyl, cycloalkenyl, cycloheteroalkyl, cycloheteroalkenyl or heteroaryl ring. Examples of aryl include phenyl and naphthyl. In one embodiment of the invention, aryl is phenyl.

As used herein, "cycloalkyl" refers to a saturated monocyclic or bicyclic, tricyclic, fused, spirocyclic or bridged ring system containing 3 to 14 carbon atoms. The cycloalkyl ring system contains more than one ring, and the rings can be connected by ring carbons. Examples of cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, indanyl, etc. In one embodiment of the invention, the cycloalkyl is selected from: cyclopropane, cyclobutane, cyclopentane and cyclohexane. In another embodiment, the cycloalkyl is selected from cyclobutane and cyclohexane. In another embodiment, the cycloalkyl is cyclobutane. In another embodiment, the cycloalkyl is cyclohexane. In another embodiment, the cycloalkyl group is selected from the group consisting of cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, bicyclo[1.1.1]pentane, bicyclo[3.1.1]heptane, bicyclo[4.1.0]heptane, bicyclo[2.2.2]octane, spiro[3.3]heptane, spiro[3.5]nonane, spiro[2.3]hexane. In another embodiment of the present invention, -C _3-9 cycloalkyl group is selected from the group consisting of cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, bicyclo[1.1.1]pentane, bicyclo[3.1.1]heptane, bicyclo[4.1.0]heptane, bicyclo[2.2.2]octane, spiro[3.3]heptane, spiro[3.5]nonane, and spiro[2.3]hexane. In another embodiment of the present invention, -C _3-9 cycloalkyl is selected from the group consisting of cyclobutane, cyclohexane, cycloheptane and bicyclo[4.1.0]heptane. In another embodiment of the present invention, -C _3-9 cycloalkyl is bicyclo[4.1.0]heptane. In another embodiment of the present invention, -C _3-9 cycloalkyl is cycloheptane. In another embodiment of the present invention, -C _3-9 cycloalkyl is cyclohexane. In another embodiment of the present invention, -C _3-9 cycloalkyl is cyclobutane.

"Cycloalkenyl" refers to a monocyclic or bicyclic, spirocyclic, fused or bridged carbocyclic ring system having the specified number of carbon atoms and containing at least one double bond. Examples of cycloalkenyl include cyclopropenyl, cyclobutenyl, cyclopentenyl, cycloheptenyl, and the like.

As used herein, "cycloheteroalkyl" refers to a saturated monocyclic or bicyclic, tricyclic, spirocyclic, fused or bridged ring system containing 3 to 14 ring atoms, wherein 1 to 4 ring atoms are independently N, NH, S (including SO and _SO2 ) and O, and the remaining ring atoms are carbon atoms. When heterocycloalkyl contains two or more rings, the rings can be fused, bridged or spirocyclic. Cycloheteroalkyl can be connected by ring carbon or ring nitrogen atoms (if present). When the ring or ring system contains one or more N atoms, N can be in the form of a quaternary amine. The nitrogen or sulfur atom (if present) of the heterocycloalkyl can be optionally oxidized to the corresponding N-oxide, S-oxide or S,S-dioxide. The cycloheteroalkyl ring can be substituted on the ring carbon and/or ring nitrogen or sulfur. Examples of cycloheteroalkyl groups include oxetanyl, piperidinyl, pyrrolidinyl, piperazinyl, morpholinyl, thiomorpholinyl, thiazolidinyl, 1,4-dioxanyl, tetrahydrofuranyl, delta-lactam, delta-lactone, silacyclopentane, silylpyrrolidine, pyrrolidinyl, azetidinyl, piperidine, piperazine, azepane, azacyclooctane, morpholine, thiomorpholine, and the like. In one embodiment of the present invention, the cycloheteroalkyl group is selected from the group consisting of azetidine, pyrrolidine, piperidine, azepane, 2-oxabicyclo[2.1.1]hexane, 3-azabicyclo[3.1.0]hexane, 3-azabicyclo[3.2.1]octane, 8-azabicyclo[3.2.1]octane, 2-azaspiro[3.5]nonane, 2-azaspiro[3.3]heptane, 3-azabicyclo[3.2.0]heptane, 1-azaspiro[3.3]heptane, 6-azaspiro[3.5]nonane, 7-azaspiro[3.5]nonane and 6-azaspiro[3.4]octane. In another embodiment, the cycloheteroalkyl group is selected from the group consisting of piperidine and azepane. In another embodiment, the C _2-8 cycloheteroalkyl is selected from the group consisting of azetidine, pyrrolidine, piperidine, azepane, 2-oxabicyclo [2.1.1] hexane, 3-azabicyclo [3.1.0] hexane, 3-azabicyclo [3.2.1] octane, 8-azabicyclo [3.2.1] octane, 2-azaspiro [3.5] nonane, 2-azaspiro [3.3] heptane, 3-azabicyclo [3.2.0] heptane, 1-azaspiro [3.3] heptane, 6-azaspiro [3.5] nonane, 7-azaspiro [3.5] nonane and 6-azaspiro [3.4] octane. In another embodiment, the C _2-8 cycloheteroalkyl is piperidine. In another embodiment, the C _2-8 cycloheteroalkyl is azepane.

"Cycloheteroalkenyl" refers to a monocyclic or bicyclic, fused, spiro or bridged ring system containing 3 to 14 ring atoms and containing at least one double bond and at least one heteroatom. Examples of cycloheteroalkenyl include dihydropyran and dihydrofuran, and the like.

"Heteroaryl" refers to a monocyclic or bicyclic or fused ring system containing 5 to 14 ring atoms, the ring atoms containing at least one ring heteroatom selected from N, NH, S (including SO and _SO2 ) and O, wherein at least one heteroatom-containing ring is an aromatic ring. The term heteroaryl includes heteroaryl groups as defined above, which are fused to aryl, cycloalkyl, cycloalkenyl, cycloheteroalkyl, cycloheteroalkenyl or heteroaromatic rings. In the case of heteroaromatic ring systems, where one or more of the rings are saturated or partially saturated and contain one or more N atoms, the N may be in the form of a quaternary amine. Any nitrogen atom of the heteroaryl group may be optionally oxidized to the corresponding N-oxide. The heteroaryl group may be optionally substituted with one or more identical or different ring system substituents. Examples of heteroaryl groups include pyrrolyl, isoxazolyl, isothiazolyl, pyrazolyl, pyridinyl, oxazolyl, oxadiazolyl, thiadiazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, furanyl, triazinyl, thienyl, pyrimidinyl, pyridazinyl, pyrazinyl, benzisoxazolyl, benzoxazolyl, benzothiazolyl, benzimidazolyl, benzopyrazolyl, benzofuranyl, benzothiophenyl (including S-oxide and dioxide), benzotriazolyl, furanyl (2,3-b) pyridinyl, quinolyl, indolyl, isoquinolyl, quinazolinyl, dibenzofuranyl, etc. In one embodiment of the present invention, heteroaryl is selected from: pyridine.

"Halogen" includes fluorine, chlorine, bromine and iodine. In one embodiment, halogen is fluorine, chlorine, bromine or iodine. In another embodiment, halogen is fluorine or chlorine. In another embodiment, halogen is chlorine, fluorine or iodine. In another embodiment, halogen is fluorine. In another embodiment, halogen is chlorine. In another embodiment, halogen is bromine. In another embodiment, halogen is iodine.

"Me" stands for methyl.

"Oxo" refers to an oxygen atom attached to another atom by a double bond and may be represented as "=0".

"Quaternary salt" refers to a cation formed by four covalent bonds to nitrogen.

When any variable (e.g., R ¹ , ^Ra, etc.) occurs more than one time in any constituent or in Formula (I), its definition on each occurrence is independent of its definition at every other occurrence. Furthermore, combinations of substituents and/or variables are permissible only if such combinations result in stable compounds. A wavy line through a bond in a substituent variable indicates a point of attachment.

"Saturated" means containing only single bonds.

"Unsaturated" means containing at least one double or triple bond. In one embodiment, unsaturated means containing at least one double bond. In another embodiment, unsaturated means containing at least one triple bond.

When any variable (e.g., R ¹ , ^Ra, etc.) occurs more than one time in any constituent or in Formula I, its definition on each occurrence is independent of its definition at every other occurrence. Furthermore, combinations of substituents and/or variables are permissible only if such combinations result in stable compounds. A wavy line through a bond in a substituent variable indicates a point of attachment.

According to standard nomenclature used in this disclosure, the terminal portion of the designated side chain is described first, followed by the adjacent functionality toward the point of attachment. For example, a C _1-5 alkylcarbonylaminoC _1-6 alkyl substituent is equivalent to:

The phrase "pharmaceutically acceptable" is used herein to refer to compounds, materials, compositions, salts, and/or dosage forms that are safe and suitable for administration to humans or animals, using sound medical judgment and in compliance with all applicable governmental regulations.

The compounds of formula I may contain one or more asymmetric centers and may therefore occur as racemates and racemic mixtures, single enantiomers, diastereomeric mixtures and individual diastereomers. The present invention is intended to encompass all such isomeric forms of the compounds of formula I.

The independent syntheses of optical isomers and diastereomers or their chromatographic separations can be achieved by appropriate modification of the methods disclosed herein, as known in the art. Their absolute stereochemistry can be determined by X-ray crystallography of crystalline products or crystalline intermediates, using, if necessary, reagents containing asymmetric centers of known absolute configuration or heavy atoms sufficient for absolute assignment.

If desired, the racemic mixture of the compound can be separated to separate the individual enantiomers. Separation can be carried out by methods well known in the art, such as coupling the racemic mixture of the compound with an enantiomer-pure compound to form a diastereomeric mixture, and then separating the individual diastereomers by standard methods (such as fractional crystallization or chromatography). The coupling reaction is usually to form a salt using an enantiomer-pure acid or base. The diastereomeric derivatives can then be converted into pure enantiomers by cleaving the added chiral residue. The racemic mixture of the compound can also be directly separated by a chromatographic method using a chiral stationary phase, which is well known in the art.

Alternatively, any enantiomer of a compound may be obtained by stereoselective synthesis by methods well known in the art using optically pure starting materials or reagents of known configuration.

Some of the compounds described herein contain olefinic double bonds, and unless specified otherwise, are intended to include both E and Z geometric isomers.

Tautomers are defined as compounds that undergo rapid proton transfer from one atom of the compound to another atom of the compound. Some of the compounds described herein may exist as tautomers with different points of hydrogen attachment. An example of this may be a ketone and its enol form, known as keto-enol tautomers. Compounds of Formula I encompass single tautomers and mixtures thereof.

In the compounds of formula I, atoms may exhibit their natural isotopic abundance, or one or more atoms may be artificially enriched in a specific isotope having the same atomic number but an atomic mass or mass number different from the atomic mass or mass number predominantly found in nature. The present invention is intended to include all suitable isotopic variants of compounds of formula I. For example, different isotopic forms of hydrogen (H) include protium ( ^1H ), deuterium ( ^2H ) and tritium ^(3H ). Protium is the main hydrogen isotope found in nature. Enrichment of deuterium may provide certain therapeutic advantages, such as increasing the half-life in vivo or reducing dosage requirements, or may provide compounds that can be used as biological sample characterization standards. Tritium is radioactive, and therefore radiolabeled compounds may be provided, which are used as tracers in metabolic or kinetic studies. The isotopically enriched compounds in formula I may be prepared without excessive experimentation using appropriate isotopically enriched reagents and/or intermediates by conventional techniques well known to those skilled in the art or by methods similar to those described in the schemes and embodiments of the present invention.

In addition, some crystalline forms of the compounds of the present invention may exist as polymorphs and are therefore intended to be included in the present invention. In addition, some compounds of the present invention may form solvates with water or common organic solvents. Such solvates are included within the scope of the present invention.

It is generally preferred to administer the compounds of the invention in the form of enantiomerically pure preparations. Racemic mixtures may be separated into their respective enantiomers by any of a variety of conventional methods. These methods include chiral chromatography, derivatization with a chiral auxiliary followed by separation by chromatography or crystallization, and fractional crystallization of diastereomeric salts.

A "stable" compound is one that can be prepared and isolated and whose structure and properties remain or can be left substantially unchanged for a period of time sufficient to allow the compound to be used for the purposes described herein (e.g., therapeutic administration to a subject). The compounds of the present invention are limited to stable compounds encompassed by formula (I).

In selecting compounds of the present invention, one of ordinary skill in the art will recognize that the various substituents (ie, ^R1 , ^R2 , etc.) should be selected according to well-known principles of chemical structure connectivity and stability.

The term "substituted" should be considered to include multiple degrees of substitution of the named substituent. Where multiple substituent moieties are disclosed or claimed, the substituted compound may be independently substituted with one or more of the disclosed or claimed substituent moieties, singly or multiple times. Independently substituted means that the (two or more) substituents may be the same or different. When a group (e.g., C ₁ -C ₈ alkyl) is represented as being substituted, such substitution may also occur when the group is part of a larger substituent (e.g., -C ₁ -C ₆ alkyl-C ₃ -C ₇ cycloalkyl and -C ₁ -C ₈ alkyl-aryl).

Unless clearly stated to the contrary in a particular context, any of the various rings and ring systems described herein may be attached to the rest of the compound at any ring atom (ie, any carbon atom or any heteroatom) if a stable compound results.

Unless expressly stated to the contrary, all ranges described herein include endpoint values. For example, a heteroaromatic ring described as containing "1 to 4 heteroatoms" means that the ring may contain 1, 2, 3 or 4 heteroatoms. It should also be understood that any range described herein includes all subranges within its scope. Therefore, for example, a heterocyclic ring described as containing "1 to 4 heteroatoms" is intended to include the following aspects: a heterocyclic ring containing 2 to 4 heteroatoms, 3 or 4 heteroatoms, 1 to 3 heteroatoms, 2 or 3 heteroatoms, 1 or 2 heteroatoms, 1 heteroatom, 2 heteroatoms, 3 heteroatoms and 4 heteroatoms. Similarly, when used with a chain (e.g., an alkyl chain), C ₁ -C ₆ means that the chain may contain 1, 2, 3, 4, 5 or 6 carbon atoms. It also includes all ranges contained herein including _C1 - _C5 , _C1 - _C4 , _C1 - _C3 , _C1 - _C2 , _C2 - _C6 , _C3 - _C6 , _C4 - _C6 , _C5 - _C6 and all other possible combinations.

It should also be noted that in the text, schemes, examples and tables herein, any carbon and heteroatom with unsatisfied valences are assumed to have the sufficient number of hydrogen atoms to satisfy the valences.

The compounds of the present invention have at least one asymmetric center and may have one or more additional centers due to the presence of certain substituents and/or substituent patterns. Therefore, the compounds of the present invention may exist as mixtures of stereoisomers, or as individual diastereoisomers, or enantiomers. All isomeric forms of these compounds, whether alone or in admixture, are within the scope of the present invention.

The term "compound" refers to the free compound, as well as any stable hydrates or solvates thereof. Hydrates are compounds in complex with water, and solvates are compounds in complex with organic solvents.

As mentioned above, the compounds of the present invention can be used in the form of pharmaceutically acceptable salts. It should be understood that, as used herein, the compounds of the present invention may also include pharmaceutically acceptable salts, as well as non-pharmaceutically acceptable salts when used as a precursor of a free compound or a pharmaceutically acceptable salt thereof or for other synthetic operations.

The term "drug resistance" refers to a strain of Gram-negative bacteria that is no longer sensitive to at least one previously effective drug; it has developed the ability to resist antibiotic attack by at least one previously effective drug. "Multidrug resistance" refers to a strain that is no longer sensitive to two or more previously effective drugs; it has the ability to resist antibiotic attack by two or more previously effective drugs. Resistant strains can pass this tolerance to their offspring. This resistance may be due to random genetic mutations in bacterial cells that change their sensitivity to a single drug or different drugs.

The term "pharmaceutically acceptable salt" refers to salts that possess the parent compound's potency and are neither biologically nor otherwise undesirable (e.g., neither toxic nor otherwise harmful to the recipients thereof). The term "pharmaceutically acceptable salt" refers to salts prepared from pharmaceutically acceptable non-toxic bases or acids, including inorganic or organic bases and inorganic or organic acids.

Salts of basic compounds encompassed within the term "pharmaceutically acceptable salts" refer to non-toxic salts of the compounds of the present invention which are generally prepared by reacting the free base with a suitable organic or inorganic acid. Representative salts of the basic compounds of the invention include, but are not limited to, the following: acetate, ascorbate, adipate, alginate, aspirate, benzenesulfonate, benzoate, bicarbonate, bisulfate, bitartrate, borate, bromide, butyrate, camphorate, camphorsulfonate, camsylate, carbonate, chloride, clavulanate, citrate, cyclopentanepropionate, diethylacetate, digluconate, dihydrochloride, dodecylsulfonate, ethylenediaminetetraacetate, edisylate, propionate dodecylsulfate, esylate, ethanesulfonate, formate, formate, fumarate, glucoheptanoate, gluconate, glutamate, glycerophosphate, glycolyl p-aminophenylarsonic acid salt (glycollyl arsenate). arsanilate), hemisulfate, heptanoate, hexanoate, hexylresorcinate, hydrabamine, hydrobromide, hydrochloride, 2-hydroxyethanesulfonate, hydroxynaphthoate, iodide, isonicotinate, isothiocyanate, lactate, lactobionate, dodecanoate, malate, maleate, mandelate, mesylate, methyl bromide, methylnitrate, methylsulfate, methanesulfonate, acetalate, 2-naphthalenesulfonate The invention also includes the following pharmaceutically acceptable salts: esters, naphthalenesulfonates, nicotinates, nitrates, N-methylglucamine ammonium salts, oleates, oxalates, pamoates (spicate), palmitates, pantothenates, pectinates, persulfates, phosphates/diphosphates, pimelates, phenylpropionates, polygalacturonates, propionates, salicylates, stearates, sulfates, subacetates, succinates, tannates, tartrates, theoclorates, thiocyanates, toluenesulfonates, triethyl iodide, trifluoroacetates, undecanoates, valerates, and the like. In addition, when the compounds of the present invention carry an acidic moiety, suitable pharmaceutically acceptable salts thereof include, but are not limited to, salts derived from inorganic bases, including aluminum, ammonium, calcium, copper, iron, ferrous, lithium, magnesium, trivalent manganese, divalent manganese, potassium, sodium, zinc, and the like. Particularly preferred are ammonium, calcium, magnesium, potassium, and sodium salts. Salts derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary and tertiary amines, cyclic amines, dicyclohexylamine and basic ion exchange resins, such as arginine, betaine, caffeine, choline, N,N-diphenylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylamine, ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucosamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine and the like. Also included are basic nitrogen-containing groups that can be quaternized with, for example, lower alkyl halides (e.g., methyl, ethyl, propyl, and butyl chlorides, bromides, and iodides); dialkyl sulfates (e.g., dimethyl, diethyl, dibutyl); and diamyl sulfates, long chain halides (e.g., decyl, dodecyl, tetradecyl, and octadecyl chlorides, bromides, and iodides), aralkyl halides (e.g., benzyl and phenethyl bromides), and other agents.

These salts can be obtained by known methods, for example, by mixing the compound of the present invention with an equal amount of a solution containing the desired acid, base, etc., and then collecting the desired salt by filtering the salt or distilling off the solvent. The compound of the present invention and its salt can form a solvate with a solvent such as water, ethanol or glycerol. Depending on the type of the side chain substituent, the compound of the present invention can simultaneously form an acid addition salt and form a salt with a base.

As mentioned above, the present invention includes pharmaceutical compositions, which include compounds of formula I of the present invention, optional other active ingredients (e.g., beta-lactamase inhibitors) and pharmaceutically acceptable carriers. The characteristics of the carrier will depend on the route of administration. "Pharmaceutically acceptable" means that the ingredients of the pharmaceutical composition must be compatible with each other, do not interfere with the effectiveness of the active ingredient, and are harmless (e.g., toxic) to its recipient. Therefore, compositions according to the present invention may include diluents, fillers, salts, buffers, stabilizers, solubilizers and other materials well known in the art in addition to inhibitors.

Also as described above, the present invention includes a method for treating bacterial infection, which includes administering a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof, optionally in combination with a beta-lactamase inhibitor, to a subject in need of such treatment. The term "subject" (or "patient") used herein refers to an animal, preferably a mammal, most preferably a human being, as a subject for treatment, observation or experiment. When referring to a compound of formula (I), the term "administering" and its variants (e.g., "administering" a compound) refers to providing the compound or a pharmaceutically acceptable salt thereof to an individual in need of treatment. When a compound or its salt is provided in combination with one or more other active agents (e.g., a beta-lactamase inhibitor), "administering" and its variants are all understood to include providing a compound or its salt and other agents simultaneously or at different times. When a combination of agents is administered simultaneously, they may be administered together in a single composition, or may be administered separately.

It should be understood that a "combination" of active agents can be a single composition containing all active agents or multiple compositions each containing one or more active agents. In the case of two active agents, the combination can be a single composition containing both agents or two separate compositions each containing one agent; in the case of three active agents, the combination can be a single composition containing all three agents, three separate compositions each containing one agent, or two compositions, one containing both agents and the other containing the third agent; and so on.

The compositions and combinations of the present invention are appropriately administered in an effective amount. The term "effective amount" as used herein refers to the amount of active compound sufficient to inhibit bacterial growth and thereby cause the response sought in cells, tissues, systems, animals or humans (i.e., an "inhibition effective amount"). In one embodiment, the effective amount is a "therapeutically effective amount" for alleviating the symptoms of the disease or condition being treated (e.g., the cure of a condition associated with bacterial infection and/or bacterial resistance). In another embodiment, the effective amount is a "preventive effective amount" for preventing the symptoms of the disease or condition being prevented. When the active compound (i.e., active ingredient) is administered in the form of a salt, the amount of the active ingredient refers to the free acid or free base form of the compound.

The administration of the composition of the present invention is suitably parenteral, oral, sublingual, transdermal, topical, intranasal, intratracheal, intraocular or intrarectal administration, wherein the composition is suitably administered by a selected route using formulation methods well known in the art (including, for example, Remington-The Science and Practice of Pharmacy, the 21st edition, the formulation preparation and administration methods described in 2006). In one embodiment, the compound of the present invention is administered intravenously in a hospital setting. In another embodiment, it is administered orally in the form of tablets or capsules. When systemically administered, the therapeutic composition is appropriately administered, for example, in a sufficient dose to achieve a blood concentration of at least about 1 microgram/mL of the inhibitor, and in another embodiment to achieve at least about 10 micrograms/mL, and at least about 25 micrograms/mL of the blood concentration. For topical administration, much lower concentrations than this may be effective, and much higher concentrations may be tolerated.

Intravenous administration of the compounds of the present invention can be carried out by reconstructing the powdered form of the compound with an acceptable solvent. Suitable solvents include, for example, saline solution (e.g., 0.9% sodium chloride injection) and sterile water (e.g., sterile water for injection, antibacterial water for injection containing methylparaben and propylparaben, or antibacterial water for injection containing 0.9% benzyl alcohol). The powdered form of the compound can be obtained by γ-irradiation of the compound or by freeze drying of the compound solution, after which the powder can be stored at room temperature or below room temperature (e.g., in a sealed vial) until it is reconstructed. The concentration of the compound in the reconstructed IV solution can be, for example, in the range of about 0.1 mg/mL to about 20 mg/mL.

The present invention also includes a method for inhibiting bacterial growth, which includes applying an inhibitory effective amount of formula (I) compound to bacterial cell culture or bacterially infected cell culture, tissue or organism. Other embodiments of the present invention include the bacterial growth inhibition method just described, wherein the compound of the present invention used is a compound of one of the above embodiments, sub-embodiments or categories. In these embodiments, the compound can optionally be used in the form of a pharmaceutically acceptable salt. The method may include applying the formula (I) compound to experimental cell cultures in vitro to prevent the growth of β-lactam-resistant bacteria. The method may also include applying the formula I compound to animals (including humans) to prevent the growth of β-lactam-resistant bacteria in vivo. In these cases, the formula (I) compound is usually co-administered with a β-lactamase inhibitor.

The methods of the presently disclosed subject matter are useful for treating these diseases because they inhibit the onset, development, or spread of the disease, cause regression of the disease, cure the disease, or otherwise improve the overall health of a subject suffering from or at risk of suffering from the disease. Thus, in accordance with the presently disclosed subject matter, the terms "treat," "treating," and grammatical variations thereof, and the phrase "therapeutic method" are intended to encompass any desired therapeutic intervention, including, but not limited to, methods for treating an existing infection in a subject (e.g., in a subject that has been exposed to a microorganism disclosed herein or is expected to be exposed to a microorganism disclosed herein), as well as methods for combating (i.e., preventing) an infection.

The compounds of the present invention can be used to treat, prevent or inhibit bacterial growth or infection caused by bacteria resistant to β-lactam antibiotics. More specifically, the bacteria can be metallo-β-lactamase-positive strains that are highly resistant to β-lactam antibiotics. The terms "slightly resistant" and "highly resistant" are well known to those of ordinary skill in the art (e.g., see Payne et al., Antimicrobial Agents and Chemotherapy 38:767-772 (1994); Hanaki et al., Antimicrobial Agents and Chemotherapy 30:11.20-11.26 (1995)). For the purposes of the present invention, a bacterial strain highly resistant to imipenem refers to a strain having an MIC of greater than 16 μg/mL to imipenem, while a bacterial strain slightly resistant to imipenem refers to a strain having an MIC of greater than 4 μg/mL to imipenem.

Compounds wherein R ⁴ is C _1-3 alkyl (eg, CH ₃ ) or cyclopropyl and R ⁵ is CO ₂ H or tetrazole have unexpected stability advantages over compounds wherein R ⁴ is hydrogen and R ⁵ is CO ₂ H or tetrazole.

The compounds of the present invention can be used in combination with beta-lactamase inhibitors to treat infections caused by beta-lactamase-producing strains, in addition to those infections included in the antibacterial spectrum of the antibiotic agent. Examples of beta-lactamase-producing bacteria are Pseudomonas aeruginosa, Pseudomonas putida, Enterobacter cloacae, Klebsiella pneumoniae, Klebsiella oxytoca, Escherichia coli, Serratia marcescens, Enterobacter aerogenes, Enterobacter agglomerans, Citrobacter freundii, Proteus mirabilis, Morganella morganii, Providencia rettgeri, Stenotrophomonas maltophilia, and Acinetobacter baumannii.

It is generally advantageous to mix or combine a compound of formula (I) with a β-lactamase inhibitor or a prodrug thereof. It is advantageous to use a compound of formula (I) in combination with a class A and class C β-lactamase inhibitor because the compound has resistance to class B β-lactamases. It is also advantageous to use a compound of formula (I) in combination with one or more class A, class C or class D β-lactamase inhibitors to further limit β-lactam susceptibility. As previously described, the compound of formula (I) and the β-lactamase inhibitor can be administered alone (simultaneously or at different times) or in the form of a single composition comprising two active ingredients.

Relebactam, tazobactam, clavulanic acid, sulbactam, avibactam, tanibocactam, nacubactam, vaborbactam, zildabactam, dulobactam, enmetazobactam and QPX7728 (ciborbactam) and other β-lactamase and metallo-β-lactamase inhibitors suitable for use in the present invention include those known to have inhibitory activity against β-lactamases.

abbreviation

Ac is acetyl; Ambient is room temperature; aq. is aqueous; ACN is acetonitrile; AcOH is acetic acid; Bn is benzyl; BOC (or Boc) is tert-butyloxycarbonyl; BOC ₂ O is di-tert-butyl dicarbonate; BuBr is butyl bromide; CBZ (or Cbz) is carbonyl phenoxy (or, benzyloxycarbonyl); CBZ-Cl is benzyloxycarbonyl chloride; CDCl ₃ is deuterated chloroform; CV or cv is column volume; D ₂ O is deuterium oxide; DBU is 1,8-diazabicyclo[5.4.0]undec-7-ene; DCC is dicyclohexylcarbodiimide; DCE is dichloroethane; DCM is dichloromethane; DEAD is diethyl azodicarboxylate; (DHQD) ₂ AQN is 1,4-bis[(5-ethyl-1-azabicyclo[2.2.2]octan-2-yl)-(6-methoxyquinolin-4-yl)methoxy]anthracene-9,10-dione; DIAD is diisopropyl azodicarboxylate; DIEA or DIPEA is diisopropylethylamine; DMA is dimethylacetamide; DMAP is 4-dimethylaminopyridine or N,N-dimethylamino-pyridine; DME is dimethoxyethane; DMF is N,N-dimethylformamide; DMSO is dimethyl sulfoxide; DPPA is diphenylphosphoryl azide; EDC is 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide; eq. or equiv. is equivalent; Et is ethyl; Et ₃ N is triethylamine; Et ₂ O is diethyl ether; EA or EtOAc is ethyl acetate; EtOH is ethanol; g is gram; FA is formic acid; h or hr or hrs is hour; HATU is 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate; hex is hexane; HMDS is hexamethyldisilazane; HPLC is high performance liquid chromatography; Int is intermediate; IPA is isopropanol; L or l is liter; LAH is lithium aluminum hydride; LC/MS or LC-MS is liquid chromatography/mass spectrometry; LDA is lithium diisopropylamide; LiHMDS is lithium hexamethyl-disilazide, M is mole; min is minute; mg is milligram; ml, mL or ML is milliliter; Me is methyl; MeCN is acetonitrile; MeO is methoxy; MeOH is methanol; MeI is methyl iodide; MPLC is medium pressure liquid chromatography; MTBE is methyl tert-butyl ether; N is normal; NaBH(OAc) ₃ is sodium triacetoxyborohydride; NBS is N-bromo-succinimide; NCS is N-chlorosuccinimide; NEt ₃ is triethanolamine; NMR is nuclear magnetic resonance; MS is mass spectrometry; MW is molecular weight; Pd/C is palladium on carbon; PdCl ₂ (dppf) ₂ is [1,1'-bis(diphenyl-phosphino)-ferrocene] dichloropalladium(II); di-t-BuDPPF-PdCl ₂ is 1,1'-bis(di-tert-butylphosphino)-ferrocene dichloropalladium; Pd(AcO) ₂ is palladium(II) acetate; PE is petroleum ether; PG is a protecting group; Ph is phenyl; Ph ₃ P is triphenylphosphine; RP is reverse phase; RP-HPLC is reverse phase high performance liquid chromatography; rt, rt, RT or RT is room temperature; sat'd is saturated; SFC is supercritical fluid chromatography; tBu is tert-butyl; tBuOH is tert-butyl alcohol; TBAF is tetrabutylammonium fluoride; TB is tert-butyldimethylsilyl; TBS-Cl is tert-butyldimethylsilyl chloride; TBDPS-Cl is tert-butyl(chloro)diphenylsilane; t-BuOH is tert-butyl alcohol; TEA is triethylamine; TFA is trifluoroacetic acid; THF is tetrahydrofuran; TLC is thin layer chromatography; TMS is trimethylsilyl; TMS-Cl is trimethylsilyl chloride; wt% is weight percentage.

Method for preparing the compound of formula (I):

The compounds disclosed herein can be prepared and tested according to the following reaction schemes and examples or modifications thereof, using readily available starting materials, reagents and conventional synthesis procedures. In these reactions, variables known to those of ordinary skill in the art can also be used, but will not be described in detail here. In addition, according to the following reaction schemes and examples, other methods for preparing the compounds disclosed herein will be apparent to those of ordinary skill in the art. Unless otherwise stated, all variables are defined as above. The following examples illustrate the present invention and its practice. The examples should not be construed as limiting the scope or spirit of the present invention. In these examples, unless otherwise stated, all temperatures are degrees Celsius, and "room temperature" refers to a temperature in the range of about 20°C to about 25°C. Reactions sensitive to moisture or air are carried out under nitrogen using anhydrous solvents and reagents. The progress of the reaction can be determined by analytical thin layer chromatography (TLC) or liquid chromatography-mass spectrometry (LC-MS) using E.Merck pre-coated TLC plates or AnHui Liangchen Guiyuan Co., Ltd. silica gel 60F-254 or GF254 (layer thickness 0.25 mm). For HPLC/MS data of intermediates, unless otherwise specified, the two main HPLC conditions used were as follows: 1) LC1 (HIMADZU C18 Xtimate 3um 2.1X30mm column with 0.9 min gradient of 10:90-80:20 v/v CH ₃ CN/H ₂ O+v 0.0375% TFA, then 0.6 min at 80:20 v/v CH ₃ CN/H ₂ O+v 0.0375% TFA; flow rate 1.2 mL/min, UV wavelength 220 & 254 nm); and 2) LC2 (Agilent C18 Xtimate 3um 2.1X30mm column with 3.0 min gradient of 10:90-80:20 v/v CH ₃ CN/H ₂ O+v 0.0375% TFA, then 0.6 min at 80:20 v/v CH ₃ CN/H ₂ O+v 0.0375% TFA was maintained for 0.5 min; flow rate was 0.8 mL/min, UV wavelength was 220 & 254 nm). For HPLC/MS data of the final product, the two main HPLC conditions used were as follows: 1) LC1: Agilent Poroshell 120EC-C18 1.9um 3.0X30mm column with 1.2 minutes 5:95-80:20 v/v _CH3CN (v 0.0375% TFA)/ _H2O (v 0.0188% TFA) gradient, followed by 1.3 minutes 80:20-95:5 v/v _CH3CN (v 0.0375% TFA)/ _H2O (v 0.0188% TFA); flow rate 1.5mL/min, UV wavelength 220 &254nm); and 2) LC2: Agilent Poroshell 120EC-C18 1.9um 3.0X30mm column with 1.2 minutes 0:100-30:70 v/v CH3CN (v 0.0375% TFA)/H2O (v 0.0188% TFA) gradient _. 0.0375% TFA)/H ₂ O (v 0.0188% TFA) gradient followed by 30:70-95:5 v/v CH ₃ CN (v 0.0375% TFA)/H ₂ O (v 0.0188% TFA) in 1.3 minutes; flow rate 1.5 mL/min, UV wavelength 220 & 254 nm); mass analysis was performed using electrospray ionization in positive ion detection mode. ¹ H NMR spectra were recorded at 400-500 MHz on Varian or Bruker instruments. Concentration of the solution was performed on a rotary evaporator under reduced pressure or by bubbling with a nitrogen stream (pipette tip connected to the end of a nitrogen tube inserted into the mixture) until the volatiles were completely removed or by freeze drying. Silica gel chromatography was performed on a pre-packed silica gel column using a commercial MPLC system. The names of the compounds in the examples were generated in Chemdraw ^TM .

General solution

Chlorochroman A is converted to intermediate B by cyanation reaction, which is subjected to functional group manipulation to obtain intermediate C. Intermediate C is aminated to obtain intermediate D, which is then deprotected to obtain compound E. Alternatively, intermediate B is converted to intermediate F by functional group manipulation. Intermediate F is aminated, and then hydroxyamidine G is reduced and the protecting group (PG) in intermediate H is removed to obtain compound E. Compound E is condensed with intermediate I to obtain intermediate J, and then the protecting group is removed to obtain the final product. Alternatively, compound E is coupled with intermediate K to directly obtain the final product.

Example 1: Preparation of Intermediate 1c

Step A-Synthesis of Intermediate-1a To a solution of 2-(diethoxyphosphoryl)-tert-butyl propionate (2150.0 g, 8.06 mol, 0.95 eq) in THF (8400 mL) stirred at ambient temperature, NaH (339.3 g, 8.48 mol, 60% purity, 1.0 eq) was added in several portions. The mixture was stirred at 30-40° C. for 3 hours. Then, a solution of 3-(2-bromo-5-chlorophenyl) propanal (2100.0 g, 8.48 mol, 1.0 eq) in THF (4200 mL) was added dropwise to the above mixture at 30-50° C. After addition, the mixture was stirred at 20-40° C. for 1 hour, then poured into ice water (10 L), and diluted with EtOAc (10 L). The organic layer was separated, and the aqueous phase was extracted with EtOAc (3 L). The combined organic layer was washed with brine (10 L) and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether:ethyl acetate (1:0-10:1) as eluent to afford Intermediate 1a. ¹ H-NMR (400 MHz, CDCl ₃ ): δ7.47 (d, J=8.5 Hz, 1H), 7.22 (d, J=2.6 Hz, 1H), 7.07 (dd, J=8.5, 2.6 Hz, 1H), 6.71 (td, J=7.5, 1.5 Hz, 1H), 2.93-2.71 (m, 2H), 2.63-2.37 (m, 2H), 1.78 (d, J=1.3 Hz, 3H), 1.52 (s, 9H).

Step B - Synthesis of Intermediate 1b Into a 50 L 4-neck round bottom flask (purged and maintained with an inert atmosphere of nitrogen) was added K ₂ CO ₃ (2188 g, 15.84 mol), potassium ferrocyanide (5218 g, 15.84 mol), potassium tetraoxodiosmium (38.1 g, 0.105 mol), (DHQD) ₂ AQN (90.1 g, 0.105 mol) and a solution of Intermediate 1a (1900 g, 5.28 mol) in tert-butyl alcohol/water (19 L/19 L). The resulting mixture was stirred at room temperature for 2 days. The reaction mixture was then extracted with ethyl acetate and the organic layers were combined and dried over anhydrous sodium sulfate. The resulting solid was filtered off. The filtrate was concentrated under vacuum and the resulting residue was purified by silica gel column eluting with ethyl acetate/petroleum ether (1/100-1/10) to give Intermediate 1b. LC-MS: m/z 417.0 [M+Na] ⁺ .

Step C-Synthesis of Intermediate 1c A solution of Cs ₂ CO ₃ (2317.2 g, 7112.01 mmol) and Pd(AcO) ₂ (39.9 g, 177.80 mmol) in toluene (14 L) was placed in a 20-L 4-neck round bottom flask (purged and maintained with an inert atmosphere of nitrogen). 2-(di-tert-butylphosphino)biphenyl (106.1 g, 355.60 mmol) was then slowly added over 30 minutes. Intermediate 1b (1400 g, 3556.01 mmol) was added to the mixture. The reaction mixture was stirred at 90° C. for 20 hours and then cooled to room temperature with a water/ice bath. The resulting solid was filtered out and the filtrate was concentrated under reduced pressure. The resulting residue was purified on a silica gel column and eluted with ethyl acetate/petroleum ether (1/100-1/5) to give Intermediate 1c. ¹ H-NMR (400 MHz, CDCl ₃ ): δ 7.07-7.00 (m, 2H), 6.67 (d, J=8.3 Hz, 1H), 4.14 (dd, J=11.0, 2.4 Hz, 1H), 3.03-2.60 (m, 2H), 2.23-1.86 (m, 2H), 1.53 (s, 9H), 1.41 (s, 3H).

Example 2: Preparation of Intermediate 2b

Step A-Synthesis of Intermediate 2a A solution of intermediate 1c (460 g, 1.47 mol) in toluene (4800 mL) was placed in a 2-L 4-neck round-bottom flask, followed by addition of sodium hydride (60 wt.%, 70.8 g, 1.77 mol) in batches at 27 ° C. The mixture was stirred at 27 ° C for 1 hour. A solution of amino 2,4,6-trimethylbenzene-1-sulfonate (380.4 g, 1.77 mol) in DCM (1200 mL) was then added dropwise at 27 ° C with stirring. The reaction mixture was stirred at 27 ° C for 2 hours. The reaction was then quenched by adding water (2000 mL) and extracted with MTBE (2×2 L). The organic layers were combined, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under vacuum. The resulting residue was purified on a silica gel column and eluted with EtOAc/PE (1:10) to give intermediate 2a. ¹ H-NMR (400 MHz, CDCl ₃ ): δ7.08-6.96 (m, 2H), 6.96 (overlapping peaks, 1H), 6.77 (d, J=9.4 Hz, 1H), 4.20 (dd, J=11.4, 1.9 Hz, 1H), 2.99-2.62 (m, 2H), 2.06 (ddt, J=13.6, 5.9, 2.1 Hz, 1H), 1.87 (dtd, J=13.6, 12.0, 5.8 Hz, 1H), 1.54 (s, 9H), 1.53 (s, 3H).

Step B - Synthesis of Intermediate 2b A solution of Intermediate 2a (500 g, 1525.27 mmol) and di-tert-butyl dicarbonate (399.00 g, 1828.18 mmol) in ethanol (5 L) was placed in a 5 L 4-neck round bottom flask. The reaction was stirred at 50 °C for 5 hours and then concentrated under vacuum. The crude product was purified by slurrying with hexanes. The solid was collected by filtration to give Intermediate 2b. ¹ H NMR (400 MHz, CDCl ₃ ): δ 7.53 (s, 1H), 6.99 (t, 2H), 6.68 (t, 1H), 4.21 (q, 1H), 2.82 (t, 2H), 2.17-2.12 (m, 2H), 1.55-1.45 (m, 21H).

Example 3: Preparation of Intermediates 3a and 3c

Step A - Synthesis of Intermediate 3a To a mixture of intermediate 2b (8.0 g, 18.69 mmol), potassium hexacyanoferrate (II) trihydrate (3.95 g, 9.35 mmol), sodium carbonate (0.248 g, 2.337 mmol) and chloro(2-dicyclohexylphosphino-2',4',6'-tri-iso-propyl-1,1'-biphenyl)(2'-amino-1,1'-biphenyl-2-yl)palladium(II) (1.471 g, 1.869 mmol) was added ACN (64 mL) and water (60 mL), both of which had been filled with nitrogen for 1 hour. Before sealing, the reaction vessel was evacuated and filled with nitrogen. The reaction was then heated at 80° C. and stirred for 2 hours. The reaction was then partitioned between ethyl acetate and water. The aqueous layer was stripped with ethyl acetate and the combined organic layers were washed with brine, dried over anhydrous sodium sulfate, and filtered through a Celite ^™ pad. The resulting filtrate was concentrated in vacuo to give a crude residue which was purified by silica gel chromatography (ISCO 220 g; 0-70% EtOAc/hexanes) to afford the desired compound. LC-MS: m/z 419.2 [M+H] ⁺ .

Step B - Synthesis of Intermediate 3b To a mixture of Intermediate 3a (4.81 g, 11.49 mmol), _MgCl2 (1.641 g, 17.24 mmol) and NaSH (1.933 g, 34.5 mmol) was added nitrogen-filled anhydrous DMF (20.5 mL) under nitrogen atmosphere. The reaction mixture was evacuated and filled with nitrogen, then capped and stirred at ambient temperature for 21 hours. The reaction was then cooled to 0°C and quenched with saturated aqueous ammonium chloride and water. The resulting mixture was extracted with ethyl acetate. The aqueous layer was back-extracted with ethyl acetate and the combined organic layers were washed with brine, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated in vacuo to give a crude residue which was purified by silica gel chromatography (ISCO, 220 g; 0-100% EtOAc/hexanes) to give the desired compound. LC-MS: m/z 453.2 [M+H] ⁺ .

Step C - Synthesis of Intermediate 3c To a solution of intermediate 3b (4.85 g, 10.72 mmol) in anhydrous ether (35 mL) was added iodomethane (0.804 mL, 12.86 mmol) at ambient temperature. The reaction was sealed and stirred for 24 hours, and then the ether supernatant was decanted. The insoluble viscous oil was triturated with ether (15 mL). The resulting oil was dried under high vacuum to give intermediate 3c. The decanted ether layers were combined and concentrated in vacuo. 1:1 hexane/ether (30 mL) was added to the resulting residue, and the resulting solid material was collected by filtration, washed with 1:1 hexane/ _Et2O (20 mL), and dried in vacuo to give an additional amount of intermediate 3c. The combined crude product was used for subsequent reactions without further purification. LC-MS: m/z 468.2[M+H] ⁺ .

Example 4: Preparation of Intermediate 4

Intermediate 4 was prepared using the method described in Patent Publication No. WO 2017/106064.

Example 5: Preparation of Intermediate 5

To a flask (250 mL) was added Intermediate 4 (10 g, 21.5 mmol) and CH ₂ Cl ₂ (43 mL), and the solution was cooled to 0°C. TFA (86 mL, 1116 mmol) was then added via syringe. The reaction mixture was stirred at 0°C for 5 hours and then concentrated in vacuo without heating to give a residue (total volume ~20 mL). DCM (100 mL) was added to the residue and the mixture was concentrated in vacuo without heating to a total volume of ~20 mL. This process was repeated four times to remove most of the TFA. Finally, the solvent was completely removed under vacuum. Water (100 mL) was added to the resulting residue. After stirring for 30 minutes, the mixture was filtered and the filter cake was rinsed with water (volume of 1 cake) and then collected. The filter cake was dissolved in 1:1 acetonitrile/water (50 mL) and the mixture was freeze-dried overnight to give Intermediate 5. LC-MS: m/z 365.3 [M+H] ⁺ . ¹ H NMR (500 MHz, DMSO-d ₆ ) δ: 9.67 (d, J=7.7 Hz, 1H), 7.88 (s, 1H), 7.57 (s, 2H), 4.59 (d, J=7.9 Hz, 1H), 1.44 (s, 3H), 1.25 (s, 3H).

Example 6: Preparation of Intermediate 6c

Step A - Synthesis of Intermediate 6a To a premixed solution of intermediate 3a (0.98 g, 2.342 mmol) in AcOH (3 mL) / pyridine (6 mL) / water (3 mL) was added sodium hypophosphite monohydrate (1.986 g, 18.73 mmol) and Raney nickel (1.45 g). The resulting mixture was stirred at 70 ° C for 12 hours. The mixture was then diluted with 100 mL of 50% EtOAc / hexane and filtered. The filtrate was washed with 100 mL of water (3×), then dried over anhydrous MgSO ₄ and concentrated under vacuum. The resulting residue was purified by silica gel chromatography (ISCO, 80 g column, eluted with 0-100% EtOAc / hexane gradient) to give intermediate 6a. MS (ESI) m / z: 422.3 [M + H] ⁺ .

Step B-Synthesis of Intermediate 6b To a mixed solution of intermediate 6a (300 mg, 0.712 mmol) in EtOH (3 mL) and water (3 mL) was added TEA (0.149 mL, 1.068 mmol), followed by hydroxylamine hydrochloride (74.2 mg, 1.068 mmol). The reaction mixture was stirred at 25 °C for 3 hours, then diluted with water (40 mL) and extracted with ethyl acetate (80 mL×3). The combined organic layer was washed with brine (40 mL), dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo. The resulting residue was purified by preparative TLC plate (SiO ₂ , 30% ethyl acetate in petroleum ether) to give intermediate 6b. MS (ESI) m/z: 459.0 [M+Na] ⁺ .

Step C - Synthesis of Intermediate 6c To a solution of intermediate 6b (500 mg, 1.145 mmol) in DMF (3.4 mL) was added 1-chloropyrrolidine-2,5-dione (199 mg, 1.489 mmol). The reaction was stirred at ambient temperature for 45 minutes. The reaction mixture was then diluted with 15 mL Et ₂ O/hexane (2:1) and washed with 20 mL water (2×). The organic layer was dried over anhydrous Na ₂ SO ₄ and then filtered, and the filtrate was concentrated in vacuo to give the crude intermediate 6c, which was used for subsequent reactions without further purification. MS (ESI) m/z: 471.3 [M+H] ⁺ .

Example 7: Preparation of Compound 1 (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((S)-pyrrolidin-3-yl)carbamimidyl)-chroman-2-yl)propanoic acid

Step A - Synthesis of Intermediate 7a To a vial containing a mixture of Intermediate 3c (0.2470 g, 0.529 mmol) and (S)-(-)-1-Boc-3-aminopyrrolidine (0.184 mL, 1.059 mmol) was added a pre-made solution of potassium acetate (0.104 g, 1.059 mmol) and acetic acid (0.182 mL, 3.18 mmol) in anhydrous methanol (5.3 mL). The reaction was heated at 70°C for 35 minutes. The reaction mixture was then directly purified by reverse phase HPLC (ISCO C18Aq 50 g; 0-100% ACN + 0.05% TFA/water + 0.05% TFA). The desired fractions were collected and concentrated in vacuo. The resulting aqueous residue was freeze dried to give the desired compound. LC-MS: m/z 605.5 [M+H] ⁺ .

Step B - Synthesis of Intermediate 7b To a vial containing intermediate 7a (0.2529 g, 0.418 mmol) was added a mixture of 2:1 trifluoroacetic acid/anhydrous dichloromethane (4.2 mL) at ambient temperature. The reaction mixture was stirred for 16.5 hours, then a solution of 4:1 MeOH/toluene (10 mL) was added to the reaction and the solution was concentrated in vacuo. The resulting residue was azeotroped with 4:1 MeOH/toluene (10 mL) and dried in vacuo to give the desired compound. LC-MS: m/z 349.2 [M+H] ⁺ .

Step C - Synthesis of Intermediate 7c Anhydrous methanol (1.2 mL) was added to a flask containing Intermediate 7b (0.043 g, 0.123 mmol) and Intermediate 4 (0.057 g, 0.123 mmol) at ambient temperature. The mixture was stirred for 2 hours and then concentrated in vacuo. The crude residue was used for subsequent reactions without further purification. LC-MS: m/z 795.5 [M+H] ⁺ .

Step D-Synthesis of Compound 1 A 2: 1 anhydrous DCM/TFA (1.2 mL) solution of intermediate 7c (0.123 mmol) was placed at ambient temperature for 1 hour. The reaction was then cooled to 0°C and MTBE (3 mL) was added under stirring, resulting in solid precipitation. The mixture was sonicated and then centrifuged (4000 rpm) to collect insoluble solids. The supernatant was decanted. MTBE was then added to the reaction again under stirring, resulting in precipitation of additional solids, which were separated by centrifugation. The resulting solid was dried in vacuo and purified by RP HPLC (XSelect CSH Prep C18; 5uM OBD; 30x 150mm; 0%-20% (ACN+0.1% FA)/(water+0.1% FA) for 15 minutes). The fractions containing the product were collected and freeze-dried to obtain the title compound as a formate salt. LC-MS: m/z 695.3[M+H] ⁺ . ¹ HNMR (500 MHz, 4:1D ₂ O/d-DMSO) δ: 7.51 (d, J = 2.2 Hz, 1H), 7.47 (dd, J = 8.6, 2.4 Hz, 1H), 6.98-6.88 (m, 2H), 4.69 (s, 1H), 4.62-4.56 (m, 1H), 4.45 (dd, J = 11.3, 2.1 Hz, 1H), 3.72 (dd, J = 13.0, 6.8 Hz, 1 H), 3.58-3.44(m, 3H), 2.95-2.78(m, 2H), 2.56-2.43(m, 1H), 2.35-2.22(m, 1H), 2.14(d, J＝13.7Hz, 1H), 1.78(dd, J＝13.5,6.0Hz, 1H), 1.58(s, 3H), 1.49(s, 3H), 1.30(s, 3H).

Example 8: Preparation of Compound 2-6

The following compounds were prepared according to the procedure of Example 7 starting from the appropriate commercially available mono-Boc protected diamine or di-Boc protected triamine.

Example 9: Preparation of Compound 7

(S)-2-((R)-6-(N-((1s,3S)-3-aminocyclobutyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 8a To a vial containing a mixture of cis-tert-butyl N-(3-aminocyclobutyl)carbamate (0.065 mL, 0.385 mmol) in anhydrous acetonitrile (1 mL) was added anhydrous acetonitrile (1 mL) solution of intermediate 3c (0.11 g, 0.238 mmol) and acetic acid (0.044 mL, 0.771 mmol). The reaction mixture was heated at 65 ° C for 2 hours, then cooled to ambient temperature and purified by reverse phase HPLC (ISCO C18Aq 50 g; eluted product in 65% ACN+0.05% TFA/water+0.05% TFA) eluted with a 0-100% ACN+0.05% TFA/water+0.05% TFA gradient. The desired fractions were collected and concentrated in vacuo. The resulting aqueous residue was distributed between brine and ethyl acetate. The brine was stripped with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and concentrated in vacuo to afford Intermediate 8a. LC-MS: m/z 605.4 [M+H] ⁺ .

Step B - Synthesis of Intermediate 8b To a vial containing Intermediate 8a (0.1108 g, 0.183 mmol) was added 2:1 trifluoroacetic acid/anhydrous dichloromethane (2 mL) at ambient temperature. The reaction mixture was stirred for 16.5 hours, then a solution of 4:1 MeOH/toluene (10 mL) was added to the reaction and the mixture was concentrated in vacuo. The resulting residue was azeotroped with 4:1 MeOH/toluene (10 mL) and dried under high vacuum to afford Intermediate 8b. LC-MS: m/z 349.16 [M+H] ⁺ .

Step C - Synthesis of Compound 7 A mixture of Intermediate 8b (0.183 mmol), Intermediate 5 (79 wt%, 0.129 g, 0.199 mmol) and powdered molecular sieves was added at ambient temperature. To a vial of 5-nitropropene (325 mesh particles; 0.100 g, dried by heating under high vacuum) was added anhydrous dimethylacetamide (1.2 mL). The reaction mixture was stirred for 18 hours and then filtered through a Celite ^™ pad. The Celite ^™ pad was washed thoroughly with MeOH. The filtrate was concentrated in vacuo and the remaining residue was cooled to 0°C, followed by the addition of DCM (6 mL) with stirring. The resulting precipitate was collected by centrifugation (4000 rpm). The supernatant was decanted and the insoluble solid was triturated with DCM (3 mL). The centrifugation and supernatant decanting steps were repeated to obtain a crude solid, which was purified by RP HPLC (XSelect CSH Prep C18; 5uMOBD; 50X 250mm; 0%-13% ACN/(water + 0.16% TFA) for 11 minutes; isocratic elution at 13% ACN/(water + 0.16% TFA) for 14 minutes). The product fractions were collected, concentrated in vacuo to remove acetonitrile, and the aqueous layer was loaded directly onto an Amberchrom CG161M column (26 g), washed with 9CV of (water + 0.1% FA), eluted with 3CV of 100% (ACN + 0.1% FA), and then 3CV of 50% (ACN + 0.1% FA) / (water + 0.1% FA). The desired fractions were collected, concentrated in vacuo, and the resulting aqueous residue was freeze-dried to give the title compound as a formate salt. LC-MS: m/z 695.2 [M + H] ⁺ . ¹ H NMR (400 MHz, 4:1 D ₂ O/d-DMSO) δ: 7.36 (s, 1H), 7.35-7.29 (m, 1H), 6.82 (d, J=8.6 Hz, 1H), 6.81 (s, 1H), 4.57 (s, 1H), 4.32 (d, J=11.6 Hz, 1H), 3.96 (t, J=8.0 Hz, 1H), 3.62-3.51 (m, 1H), 2.85 (dt, J=7.5, 2.6 Hz, 2H), 2.72 (m, 2H), 2.27 (q, J=8.9 Hz, 2H), 2.01 (d, J=12.2 Hz, 1H), 1.65 (m 1H), 1.45 (s, 3H), 1.36 (s, 3H), 1.18 (s, 3H).

Example 10: Preparation of Compound 8-20

Starting from the appropriate commercially available mono-Boc protected diamine, the following compounds were prepared according to the procedure of Example 9:

Example 11: Preparation of Compound 21

(S)-2-((R)-6-(N-(7-azaspiro[3.5]nonan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A-Synthesis of intermediate 9a To a mixture of tert-butyl 2-amino-7-azaspiro [3.5] nonane-7-formate (92.6 mg, 0.386 mmol) in anhydrous acetonitrile (1 mL) was added anhydrous acetonitrile (1 mL) solution of intermediate 3c (0.11 g, 0.238 mmol) and acetic acid (0.044 mL, 0.771 mmol). The reaction mixture was heated at 65 ° C for 2 hours, then cooled to ambient temperature, and purified by reversed-phase HPLC (ISCO C18Aq 50 g; eluted product in 65% ACN + 0.05% TFA / water + 0.05% TFA) with a gradient elution of 0-100% ACN + 0.05% TFA / water + 0.05% TFA. The desired fractions were collected and concentrated in vacuo. The resulting aqueous residue was distributed between brine and ethyl acetate, and further stripped with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and then concentrated in vacuo to afford Intermediate 9a. LC-MS: m/z 659.5 [M+H] ⁺ .

Step B - Synthesis of Intermediate 9b To a vial containing Intermediate 9a (0.1145 g, 0.174 mmol) was added 2:1 trifluoroacetic acid/anhydrous dichloromethane (2 mL) at ambient temperature. The reaction was stirred for 16.5 hours, then a solution of 4:1 MeOH/toluene (10 mL) was added to the reaction and the mixture was concentrated in vacuo. The resulting residue was azeotroped with 4:1 MeOH/toluene (10 mL) and dried under high vacuum to afford Intermediate 9b. LC-MS: m/z 403.37 [M+H] ⁺ .

Step C - Synthesis of Compound 21 A mixture of Intermediate 9b (0.174 mmol), Intermediate 5 (79% by weight, 0.12 g, 0.260 mmol) and powdered molecular sieves was added at ambient temperature. To a vial of 5-nitropropene (325 mesh particles; 0.100 g, dried by heating under high vacuum) was added anhydrous dimethylacetamide (1.2 mL). The reaction mixture was stirred for 19 hours and then filtered through a Celite ^™ pad. The Celite ^™ pad was washed with MeOH and the filtrate was concentrated in vacuo. The remaining residue was cooled to 0°C and then DCM (6 mL) was added and the mixture was stirred slowly. The resulting solid was collected by centrifugation (4000 rpm). The supernatant was decanted and the insoluble solid was triturated with DCM (3 mL). Repeated centrifugation and decanting of the supernatant gave the crude product, which was purified by RP HPLC (XSelect CSH Prep C18; 5uM OBD; 50X 250mm; 0%-13% ACN/(water + 0.16% TFA) for 11 minutes; isocratic elution at 13% ACN/(water + 0.16% TFA) for 14 minutes). The product fractions were collected and concentrated in vacuo. The resulting aqueous layer was directly loaded onto an Amberchrom CG161M column (26 g), washed with 9 CV of (water + 0.1% FA), eluted with 3 CV of 100% (ACN + 0.1% FA), and then 3 CV of 50% (ACN + 0.1% FA) / (water + 0.1% FA). The product fractions were collected, concentrated in vacuo, and the resulting aqueous residue was freeze-dried to give compound 21 as a formate salt. LC-MS: m / z 749.6 [M + H] ⁺ . ¹ H NMR (400 MHz, 4:1 D ₂ O/CD ₃ CN) δ: 7.51-7.37 (m, 2H), 7.01-6.86 (m, 2H), 4.67 (s, 1H), 4.48 (d, J=10.5 Hz, 1H), 4.23 (t, J=7.8 Hz, 1H), 3.13 (dt, J=25.1, 5.6 Hz, 4H), 2.85 (m, 2H), 2.52 (dd, J=11.8, 9.5 Hz, 2H), 2.19–2.01 (m, 3H), 1.90-1.73 (m, 5H), 1.58 (s, 3H), 1.49 (s, 3H), 1.30 (s, 3H).

Example 12: Preparation of Compounds 22 and 23

(S)-2-((R)-6-(N-((2r,4S)-6-azaspiro[3.4]octan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((2s,4R)-6-azaspiro[3.4]octan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid*

Step A - Synthesis of Intermediate 10a To a vial containing tert-butyl 2-amino-6-aza-spiro[3.4]octane-6-carboxylate (73.0 mg, 0.321 mmol) and intermediate 3c (0.1496 g, 0.321 mmol) was added a pre-made solution of acetic acid (0.055 mL, 0.962 mmol) in anhydrous acetonitrile (2 mL). The reaction mixture was heated at 70° C. for 2.5 hours, then cooled to ambient temperature and eluted by reverse phase HPLC (ISCO C18 Aq50 g; product eluted in 65% ACN+0.05% TFA/water+0.05% TFA) eluted with a 0-100% ACN+0.05% TFA/water+0.05% TFA gradient. The desired fractions were collected and concentrated in vacuo. The resulting aqueous residue was partitioned between brine and ethyl acetate and further stripped with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and concentrated in vacuo to give the desired compound. LC-MS: m/z 645.6 [M+H] ⁺ .

Step B - Synthesis of Intermediate 10b To a solution of intermediate 10a (0.1832 g, 0.284 mmol) in anhydrous DCM (1.5 mL) was added triethylamine (0.119 mL, 0.852 mmol) followed by a solution of (Boc) _2O (0.099 mL, 0.426 mmol) in DCM (1.5 mL). The reaction mixture was stirred at ambient temperature for 6 hours. The reaction was then partitioned between EtOAc and saturated aqueous _NH4Cl . The organic layer was separated, dried over anhydrous sodium sulfate, and concentrated in vacuo. The resulting residue was purified by silica gel chromatography (Isco 24 g column; 0-100% (3:1 EtOAc/EtOH)/hexanes) to afford the desired diastereomeric compound. LC-MS: m/z 745.5 [M+H] ⁺ . The diastereomers were separated by chiral chromatography (IA, 2X 15 cm column; IPA + 0.25% IBA/CO ₂ ) to give two diastereomers: intermediate 10b-1 (peak 1); LC-MS: m/z 745.7 [M+H] ⁺ , intermediate 10b-2 (peak 2); LC-MS: m/z 745.7 [M+H] ⁺ .

Step C - Synthesis of Intermediate 10c-2 To a vial containing intermediate 10b-2 (95 mg, 0.128 mmol) was added 2:1 trifluoroacetic acid/anhydrous dichloromethane (1.3 mL) at ambient temperature. The reaction was stirred for 16 hours. A solution of 4:1 MeOH/toluene (5 mL) was then added and the mixture was concentrated in vacuo. The resulting residue was azeotroped with MeOH (5 mL) and then dried under high vacuum to give the desired compound. LC-MS: m/z 389.3 [M+H] ⁺ .

Intermediate 10c-1 was prepared according to step C using intermediate 10b-1 (37 mg, 0.050 mmol); LC-MS: m/z 389.3 [M+H] ⁺ .

Step D - Synthesis of Compound 22 At ambient temperature, a mixture of intermediate 10c-2 (0.128 mmol), intermediate 5 (80 wt%, 0.0525 g, 0.115 mmol) and powdered molecular sieves was added. To a vial of 5% paraformaldehyde (325 mesh particles; 0.100 g, dried by heating under high vacuum) was added anhydrous dimethylacetamide (0.5 mL). The reaction mixture was stirred for 16.5 hours, then the molecular sieves were removed by filtration and the solids were washed with MeOH. The filtrate was concentrated in vacuo and the resulting residue was cooled to 0°C, then DCM (5 mL) was added and stirred slowly. The resulting solids were collected by centrifugation (4000 rpm). The supernatant was decanted and the insoluble solids were triturated with DCM (5 mL). Repeated centrifugation and decanting of the supernatant gave a crude solid. The solid was purified by reverse phase HPLC (XSelect CSH Prep C18; 5uM OBD; 50X250mm; 0%-30% ACN/(water + 0.16% TFA) for 12 minutes; isocratic elution at 17-18% ACN/(water + 0.16% TFA) for 5 minutes). The product fractions were collected and concentrated in vacuo, and the resulting aqueous layer was loaded directly onto an Amberchrom CG161M column (26 g), washed with 9 CV of (water + 0.1% FA), eluted with 3 CV of 100% (ACN + 0.1% FA), and then 3 CV of 50% (ACN + 0.1% FA) / (water + 0.1% FA). The product fractions were collected and concentrated in vacuo, and the resulting aqueous residue was freeze-dried to give the title compound as a formate salt. ¹ HNMR (500 MHz, 4:1D ₂ O/d-DMSO)δ:7.50-7.42(m,2H),6.99-6.91(m,2H),4.68(s,1H),4.48(d,J＝9.5Hz,1H),4.36(ddd,J＝14.4,8.3,6.1Hz,1H),3.33(t,J＝7.6Hz,2H),3.07-2.99(m,2H),2.88(m,2H),2.63-2.55(m,2H),2.17(t,J＝7.3Hz,3H),2.07-1.97(m,2H),1.88-1.71(m,1H),1.59(s,3H),1.49(s,3H),1.30(s,3H).LC-MS:m/z735.8[M+H] ⁺ According to step D of Example 12, compound 23 was prepared using intermediate 10c-1 (0.050 mmol). ¹ H NMR (500 MHz, 4:1 D ₂ O/d-DMSO) δ: 7.52-7.44 (m, 2H), 6.98 (d, J=8.6 Hz, 1H), 6.92 (s, 1H), 4.68 (s, 1H), 4.46 (d, J=10.6 Hz, 1H), 4.25-4.18 (m, 1H), 3.29 (t, J=7.3 Hz, 2H), 2.88-2.77 (m, 4H), 2.74-2.67 (m, 2H), 2.11-2.18 (m, 3H), 2.05 (p, J=8.2, 7.6 Hz, 2H), 1.84-1.73 (m, 1H), 1.58 (s, 3H), 1.49 (s, 3H), 1.31 (s, 3H). LC-MS: m/z 735.5 [M+H] ⁺ . *Each compound is a single diastereomer, the stereochemistry of the carbon marked by the * is not specified.

Example 13: Preparation of Intermediate 11f

Step A-Synthesis of Intermediate 11a 1,3-cyclohexadiene (25 g, 0.311 mol) was added dropwise to a stirred solution of N-Boc-hydroxylamine (31.15 g, 0.233 mol) in dry methanol (1 L) cooled to 0°C, and then an aqueous solution (750 mL) of sodium metaperiodate (52.6 g, 0.246 mol) was added dropwise over 30 minutes. The reaction mixture was stirred at room temperature for 16 hours and then filtered. The solid was washed with EtOAc (2×200 mL) and the filtrate was concentrated under reduced pressure at 38°C. The residue was dissolved in EtOAc and washed with brine. The organic layer was dried over Na ₂ SO ₄ and concentrated under reduced pressure. The residue was purified by silica gel chromatography with a 3-10% EtOAc/DCM gradient elution to give Intermediate 11a. ¹ H NMR (400 MHz, CDCl ₃ ): δ 6.56-6.50 (m, 2H), 4.75-4.70 (m, 2H), 2.2-2.0 (m, 2H), 1.46 (s, 9H), 1.39-1.34 (m, 2H).

Step B-Synthesis of intermediate 11b To a stirred solution of acetonitrile (2L)/water (100mL) of intermediate 11a (50g, 0.2367mol) heated to 55°C was added molybdenum hexacarbonyl (31.27g, 0.11848mol) at one time. The reaction mixture was refluxed at 100°C for 3 hours and then stirred at room temperature for 16 hours. The reaction mixture was then filtered through Celite ^TM and the filtrate was concentrated under reduced pressure at 40°C. The resulting residue was purified by silica gel chromatography, eluted with 40% EtOAc/petroleum ether to obtain intermediate 11b. ¹ H NMR (300 MHz, CDCl ₃ ) δ: 5.86-5.80 (m, 1H), 5.78-5.75 (m, 1H), 4.55 (brs, 1H), 4.17-4.1 (m, 2H), 1.9-1.75 (m, 2H), 1.74-1.6 (m, 2H), 1.46 (s, 9H).

Step C - Synthesis of Intermediate 11c A stirred solution of intermediate 11b (30 g, 0.14 mol) in dry dichloromethane (600 mL) was purged with argon for 15 minutes. It was then cooled to 0°C and Dess-Martin periodinane (89.5 g, 0.211 mol) was subsequently added. The reaction mixture was stirred at room temperature for 1 hour, then diluted with dichloromethane (500 mL), washed with 10% aqueous sodium thiosulfate solution (2×500 mL), 10% sodium bicarbonate (2×500 mL), water (500 mL) and brine (500 mL). The organic layer was separated, dried over anhydrous Na ₂ SO ₄ and filtered. The filtrate was concentrated under reduced pressure to give intermediate 11c, which was used in the next step without further purification. ¹ H NMR (300 MHz, CDCl ₃ ) δ: 6.87-6.80 (m, 1H), 6.1-5.9 (m, 1H), 4.7 (brs, 1H), 4.5 (brs, 1H), 2.56-2.44 (m, 2H), 2.4-2.3 (m, 1H), 1.92-1.85 (m, 1H), 1.47 (s, 9H).

Step D-Synthesis of intermediate 11d To a suspension of NaH (7.4 g, 0.184 mol) in anhydrous DMSO (900 mL) was added trimethyl sulfoxide iodide (40.6 g, 0.184 mol). The mixture was cooled to 15 ° C, and then a solution of intermediate 11c (30 g, 0.142 mol) in DMSO (300 mL) was added dropwise. The reaction mixture was then stirred at room temperature for 5 hours, followed by the addition of ice. The mixture was extracted with a solution of 50% EtOAc in petroleum ether (3×500 mL). The combined organic layers were dried over Na ₂ SO ₄ and filtered. The filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (silica gel 60-120 mesh, 25% EtOAc in petroleum ether) to give intermediate 11d. ¹ H NMR (400 MHz, CDCl ₃ ): δ 4.94 (brs, 1H), 4.20 (brs, 1H), 2.25-2.17 (m, 2H), 1.8-1.7 (m, 4H), 1.41 (s, 9H), 1.9-1.65 (m, 2H).

Step E - Synthesis of Intermediate 11e To a solution of intermediate 11d (0.3482 g, 1.546 mmol) in anhydrous dichloromethane (7 mL) was added benzylamine (219 μL, 2.009 mmol) at ambient temperature. The reaction was stirred for 10 minutes, then NaBH(OAc) ₃ (0.655 g, 3.09 mmol) and AcOH (1 μL, 0.017 mmol) were added. The reaction mixture was stirred for 2 hours, then quenched by the slow addition of NaOH (1 N, 5 mL) at 0°C. The resulting mixture was extracted with EtOAc. The organic layer was washed with brine, dried over Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo. The resulting residue was purified by silica gel chromatography (Isco Gold 12 g column; 0-100% EtOAc/hexanes) to give the desired compound. LC-MS: m/z 317.6 [M+H] ⁺ .

Step F - Synthesis of Intermediate 11f A mixture of intermediate 11e (1.9206 g, 6.07 mmol) and Pd/C (10 wt%, 0.3942 g, 3.70 mmol) in anhydrous ethanol (20.23 mL) was hydrogenated under atmospheric H at ambient temperature _for 48 h. The reaction mixture was filtered through a Celite ^™ pad under _N atmosphere. The pad was washed with MeOH and the filtrate was concentrated in vacuo to give the desired compound. LC-MS: m/z 227.2 [M+H] ⁺ .

Example 14: Preparation of Compounds 24-27

The following compound was prepared from intermediate 11f according to the procedure of Step A to Step D of Example 12, wherein the diastereomers were separated in Step B by chiral chromatography (ChiralTek Enantiocel C9-5, 3X 25 cm column; MeOH/CO ₂ followed by AD-H, 3X 25 cm, iPrOH/CO ₂ ) to give 4 independent diastereomers (the absolute stereochemistry of the *-marked carbon center is not specified; the figures shown represent the relative stereochemistry).

Example 15: Preparation of Compound 28

(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-(piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid

Step A - Synthesis of Intermediate 12a To a vial containing a mixture of Intermediate 3c (1.264 g, 2.71 mmol) and 4-amino-1-Boc-piperidine (1.086 g, 5.42 mmol) was added a pre-made solution of potassium acetate (0.532 g, 5.42 mmol) and acetic acid (0.930 mL, 16.26 mmol) in anhydrous methanol (27 mL). The reaction was heated at 70°C for 30 minutes and then partitioned between EtOAc and cold saturated aqueous _NaHCO3 /brine. The organic layer was separated, dried over _Na2SO4 , filtered, and the filtrate concentrated in vacuo to give a foam. The foam was purified by reverse phase chromatography (ISCO C18 ₁₃₀ g; 0-100% ACN + 0.05% TFA/water + 0.05% TFA). The product fractions were concentrated in vacuo and the resulting aqueous residue was extracted with EtOAc (2x). The combined organic layers were dried over _Na2SO4 , filtered, and the filtrate was concentrated in vacuo to afford the desired compound. _LC -MS: m/z 619.6 [M+H] ⁺ .

Step B - Synthesis of Intermediate 12b To a vial containing Intermediate 12a (0.9292 g, 1.502 mmol) was added 2:1 trifluoroacetic acid/anhydrous dichloromethane (15 mL) at ambient temperature. The reaction was stirred for 16.5 hours, then a solution of 4:1 MeOH/toluene (25 mL) was added to the reaction and the mixture was concentrated in vacuo. The resulting residue was azeotroped with 4:1 MeOH/toluene (25 mL) and dried in vacuo to give the desired compound. LC-MS: m/z 363.32 [M+H] ⁺ .

Step C - Synthesis of Intermediate 12c To a flask containing Intermediate 12b (0.544 g, 1.502 mmol) and Intermediate 4 (0.6722 g, 1.447 mmol) was added 30% toluene in anhydrous methanol (15 mL) at ambient temperature. The reaction was stirred for 3 hours and then concentrated in vacuo. The resulting residue was purified by reverse phase chromatography (Isco C18Aq 415 g column; 30 minutes of 0-40% ACN + 0.05% TFA/water + 0.05% TFA) and the aqueous product fractions were concentrated in vacuo. The aqueous residue was then loaded onto an Amberchrom CG161M column (26 g), washed with 9 CV of (water + 0.05% TFA), eluted with 3 CV of 100% (ACN + 0.05% TFA), and then 3 CV of 50% (ACN + 0.05% TFA) / (water + 0.05% TFA). The product fractions were collected, concentrated in vacuo, and the resulting aqueous residue was freeze-dried to give the desired compound. LC-MS: m / z 809.6 [M + H] ⁺ .

Step D-Synthesis of Compound 28 To intermediate 12c (0.3580 g, 0.443 mmol) was added 2: 1 anhydrous DCM/TFA (4.4 mL) at ambient temperature. The reaction mixture was stirred for 1 hour and then cooled to 0°C. MTBE (10 mL) was added to the reaction under stirring, resulting in solid precipitation. The reaction mixture was sonicated and then centrifuged (4000 rpm) to collect insoluble solids. The supernatant was decanted and the MTBE (5 mL) washing and centrifugation were repeated again. The resulting solid was dried in vacuo and then purified by reverse phase HPLC (XSelect CSH Prep C18; 5uM OBD; 30X 150mm; 0%-15% (ACN+0.1% FA)/(water+0.1% FA) for 15 minutes). The product fractions were collected and freeze-dried to obtain the title compound as a formate salt. LC-MS: m/z709.6[M+H] ⁺ . ¹ HNMR (400MHz, 4:1D ₂ O/d-DMSO)δ:7.41-7.28(m,2H),6.85(d,J＝8.7Hz,1H),6.80(s,1H),4.58(s,1H),4.34(d,J＝10.7Hz,1H),3.89-3.80(m,1H),3.41(d,J＝13.4Hz,2H),3.01(t,J＝11.9Hz,2H),2.82-2.68(m,2H),2.19(d,J＝13.5Hz,2H),2.02(d,J＝13.6Hz,1H),1.87-1.72(m,2H),1.70-1.60(m,1H),1.45(s,3H),1.37(s,3H),1.19(s,3H).

Example 16: Preparation of Compounds 29 and 30

(S)-2-((R)-6-(N-(1-((R)-3-amino-2-hydroxypropyl)piperidin-4-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-(1-((S)-3-amino-2-hydroxypropyl)piperidin-4-yl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 13a To a vial containing (S)-1-(tert-butoxycarbonyl)-2,3-oxiranylmethylamine (0.095 g, 0.546 mmol) and 4-CBZ-aminopiperidine (0.1066 g, 0.455 mmol) was added anhydrous methanol (4.6 mL) at ambient temperature. The reaction mixture was heated to 60°C for 4 hours and then concentrated in vacuo. The resulting residue was purified by silica gel chromatography (Isco Gold 12 g column; 0-100% (3:1 EtOAc/EtOH)/hexanes) to give the desired compound. LC-MS: m/z 409.3 [M+H] ⁺ .

Step B - Synthesis of Intermediate 13b A vial containing Intermediate 13a (0.185 g, 0.455 mmol) and Pd/C (10 wt%, 0.0527 g, 0.050 mmol) was evacuated and filled with _N2 (3x). Anhydrous MeOH (4.6 mL) was then added under _N2 and the reaction vessel was evacuated and filled with _N2 (3x) and then placed under _1H2 atmosphere (balloon). The reaction mixture was stirred for 4 hours and then filtered through a Celite ^™ pad. The Celite ^™ pad was washed with methanol and the resulting filtrate was concentrated in vacuo to give the desired compound. LC-MS: m/z 274.2 [M+H] ⁺ .

Step C - Synthesis of Intermediate 13c To a mixture of Intermediate 3c (95.9 mg, 0.161 mmol) and Intermediate 13b (81.4 mg, 0.298 mmol) was added a pre-formulated solution of potassium acetate (31.7 mg, 0.323 mmol) and acetic acid (0.055 ml, 0.968 mmol) in anhydrous methanol (1.6 ml). The reaction mixture was stirred at room temperature for 1.5 hours and then concentrated in vacuo. The resulting residue was purified by reverse phase HPLC (ISCO C18 13 g; 0-100% ACN + 0.05% TFA/water + 0.05% TFA). The product fractions were collected and freeze-dried to give the desired compound. LC-MS: m/z 692.6 [M+H] ⁺ .

Step D - Synthesis of Intermediate 13d To a vial containing Intermediate 13c (75.8 mg, 0.110 mmol) was added 2:1 trifluoroacetic acid/anhydrous dichloromethane (1.1 mL) at ambient temperature. The reaction mixture was stirred for 16.5 hours, then a solution of 4:1 MeOH/toluene (5 mL) was added to the reaction and the resulting mixture was concentrated in vacuo. The resulting residue was azeotroped again with 4:1 MeOH/toluene (5 mL) and then dried in vacuo to give the desired compound. LC-MS: m/z 436.2 [M+H] ⁺ .

Step E - Synthesis of Intermediate 13e Anhydrous methanol (1.1 mL) was added to a flask containing intermediate 13d (0.048 g, 0.110 mmol) and intermediate 4 (0.051 g, 0.110 mmol) at ambient temperature. The reaction was stirred for 2 hours and then concentrated in vacuo. The resulting residue was purified by reverse phase chromatography (Isco C18Aq 415 g column; 30 minutes of 0-40% ACN + 0.05% TFA / water + 0.05% TFA) and the aqueous product fraction was concentrated in vacuo. The resulting aqueous residue was loaded onto an Amberchrom CG161M column (26 g), washed with 9 CV of (water + 0.05% TFA), eluted with 3 CV of 100% (ACN + 0.05% TFA), and then 3 CV of 50% (ACN + 0.05% TFA) / (water + 0.05% TFA). The product fractions were collected, concentrated in vacuo, and the resulting aqueous residue was freeze-dried to give the desired compound. LC-MS: m/z 882.7 [M+H] ⁺ .

Step F - Synthesis of Compounds 29 and 30 To intermediate 13e (97 mg, 0.110 mmol) was added 2:1 anhydrous DCM/TFA (1.1 mL) at ambient temperature. The reaction mixture was stirred for 1 hour and then cooled to 0°C, followed by the addition of MTBE (3 mL) and stirring. The resulting mixture was sonicated and then centrifuged (4000 rpm) to collect the insoluble solids. The supernatant was decanted and the MTBE wash and centrifugation steps were repeated. The resulting solid was dried in vacuo and purified by RP HPLC (XSelect CSH PrepC18; 5uM OBD; 30X 150mm; 0%-20% (ACN+0.1% FA)/(water+0.1% FA) for 15 minutes). The product fractions were collected and freeze-dried to give the title compound as a formate salt. LC-MS: m/z 782.6 [M+H] ⁺ . ¹ HNMR (500MHz, 4:1D ₂ O/d-DMSO)δ:7.50-7.38(m,2H),6.96(d,J＝8.6Hz,1H),6.90(s,1H),4.67(s,1H),4.48(d,J＝11.3Hz,1H),4.39-4.32(m,1H),4.02-3.93(m,1H),3.74-3.60(m,2H),3.3 4-3.11(m,5H),2.97(dd,J＝13.3,9.0Hz,1H),2.86(t,J＝17.6Hz,2H),2.39-2.27(m,2H),2.20-1.94(m,3H),1.84-1.72(m,1H),1.58(s,3H),1.48(s,3H),1.30(s,3H).

According to the procedure of step A to step F of Example 16, compound 30 was prepared from (R)-1-(tert-butoxycarbonyl)-2,3-oxiranyl-methylamine. Compound 30: LC-MS: m/z 782.3 [M+H] ⁺ . ¹ H NMR (500 MHz, 4:1 D ₂ O/d-DMSO) δ: 7.49-7.40 (m, 2H), 6.96 (d, J=8.6 Hz, 1H), 6.90 (s, 1H), 4.67 (s, 1H), 4.46 (dd, J=11.3, 2.0 Hz, 1H), 4.39-4.31 (m, 1H), 4.02-3.93 (m, 1H), 3.74-3.58 (m, 2H), 3.32-3.20 (m , 3H), 3.17(dd, J＝13.3,3.2Hz,2H),2.97(dd, J＝13.3,8.9Hz,1H),2.87(d, J＝16.3Hz,2H),2.33(bs,2H),2.20-1.96(m,3H),1.81-1.75(m,1H),1.57(s,3H),1.48(s,3H),1.30(s,3H).

Example 17: Preparation of Compound 31

(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((R)-azepan-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid

Step A - Synthesis of Intermediate 14a To a vial containing a mixture of 2-methyl-2-propyl (4S)-4-amino-1-aziridine carboxylate (91.9 mg, 0.429 mmol) and Intermediate 3c (0.100 g, 0.214 mmol) was added a solution of potassium acetate (0.631 mg, 0.643 mmol) and acetic acid (0.07 mL, 1.286 mmol) in anhydrous methanol (2 mL). The reaction was heated at 70 °C for 20 minutes, then cooled, diluted with EtOAc (2 mL), and washed with saturated aqueous NaHCO ₃ solution (1 mL). The organic layer was separated, dried over Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo to give a residue which was purified by reverse phase HPLC (XSelect CSH Prep C18; 5uMOBD; 30X 150mm; 35%-70% (ACN+0.05% TFA)/(water+0.05% TFA) over 8 minutes). The product fractions were collected and freeze-dried to give the desired compound. LC-MS: m/z 633.5 [M+H] ⁺ .

Step B - Synthesis of Intermediate 14b To a vial containing Intermediate 14a (0.0652 g, 0.166 mmol) was added 2:1 trifluoroacetic acid/anhydrous dichloromethane (1.4 mL) at ambient temperature. The reaction was stirred for 16.5 hours, then a solution of 4:1 MeOH/toluene (2 mL) was added to the reaction and the mixture was concentrated in vacuo. The resulting residue was azeotroped with 4:1 MeOH/toluene (2 mL) and dried in vacuo to give the desired compound. LC-MS: m/z 377.3 [M+H] ⁺ .

Step C - Synthesis of Intermediate 14c To a flask containing Intermediate 14b (0.166 mmol) and Intermediate 4 (0.076 g, 0.164 mmol) was added anhydrous methanol (1.7 mL) at ambient temperature. The reaction was stirred for 3 hours and then concentrated in vacuo. The resulting residue was purified by reverse phase HPLC (XSelect CSH Prep C18; 5 uM OBD; 30X 150 mm; 12%-42% (ACN+0.05% TFA)/(water+0.05% TFA) over 15 minutes) to give the desired compound. LC-MS: m/z 823.9 [M+H] ⁺ .

Step D-Synthesis of Compound 31 To intermediate 14c (47.1 mg, 0.057 mmol) was added 2: 1 anhydrous DCM/TFA (572 μL) at ambient temperature. The reaction mixture was stirred for 1 hour and then cooled to 0°C, followed by the addition of MTBE (3 mL) with stirring to obtain a precipitate. The mixture was sonicated and then centrifuged (4000 rpm) to collect the insoluble solid. The supernatant was decanted and the MTBE wash and centrifugation steps were repeated. The resulting solid was dried in vacuo and purified by RP HPLC (XSelect CSH PrepC18; 5 uM OBD; 19X 150 mm; 0%-40% (ACN+0.05% FA)/(water+0.05% FA) over 24 minutes; flow rate = 17.0 mL/min.; monitor and collect 254 nM and 215 nM; product eluted in 17% (ACN+0.05% FA)/(water+0.05% FA)). The product fractions were collected and freeze-dried to give the title compound as a formate salt. LC-MS: m/z 723.4 [M+H] ⁺ . ¹ H NMR (500 MHz, 4:1 D ₂ O/d-DMSO) δ: 7.47 (s, 1H), 7.44 (dd, J=8.6, 2.3 Hz, 1H), 6.97 (d, J=8.6 Hz, 1H), 6.91 (s, 1H), 4.69 (s, 1H), 4.46 (dd, J=11.1, 2.0 Hz, 1H), 3.95 (dq, J=9.0, 4.5 Hz, 1H), 3.45 (dd, J=11.1, 2.0 Hz, 1H). =13.5,6.5Hz,1H),3.40-3.30(m,1H),3.30-3.17(m,2H),2.92-2.82(m,2H),2.43-2.22(m,2H),2.20-1.99(m,3H),1.91-1.73(m,3H),1.57(s,3H),1.49(s,3H),1.31(s,3H).

Example 18: Preparation of Compound 32

(S)-2-((R)-6-(N-((1r,4R)-4-aminocyclohexyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 15a To a vial containing a mixture of trans-N-Boc-1,4-cyclohexanediamine (91.9 mg, 0.429 mmol) and Intermediate 3c (0.100 g, 0.214 mmol) was added potassium acetate (0.631 mg, 0.643 mmol) and acetic acid (0.07 mL, 1.286 mmol) in anhydrous methanol (2 mL). The reaction was heated at 70 °C for 20 min, then cooled, diluted with EtOAc (2 mL), and washed with saturated NaHCO ₃ (1 mL). The organic layer was separated, dried over Na ₂ SO ₄ , filtered, and the filtrate concentrated in vacuo to give a foam. The foam was purified directly by reverse phase HPLC (XSelect CSH Prep C18; 5uM OBD; 30X150mm; 35%-70% (ACN+0.05% TFA)/(water+0.05% TFA) over 8 minutes). Product fractions were collected and dried in Genevac ^TM to give the desired compound. LC-MS: m/z 633.5 [M+H] ⁺ .

Step B - Synthesis of Intermediate 15b To a vial containing Intermediate 15a (0.0567 g, 0.151 mmol) was added 2:1 trifluoroacetic acid/anhydrous dichloromethane (1.4 mL) at ambient temperature. The reaction was stirred for 16.5 hours, then a solution of 4:1 MeOH/toluene (2 mL) was added to the reaction and the mixture was concentrated in vacuo. The resulting residue was azeotroped with 4:1 MeOH/toluene (2 mL) and dried in vacuo to give the desired compound. LC-MS: m/z 377.3 [M+H] ⁺ .

Step C - Synthesis of Intermediate 15c To a flask containing Intermediate 15b (0.151 mmol) and Intermediate 4 (0.067 g, 0.144 mmol) was added anhydrous methanol (1.5 ml) at ambient temperature. The reaction was stirred for 3 hours and then concentrated in vacuo. The resulting residue was purified by reverse phase HPLC (XSelect CSH Prep C18; 5 uM OBD; 30X 150 mm; 12%-42% (ACN+0.05% TFA)/(water+0.05% TFA) over 15 minutes) to give the desired compound. LC-MS: m/z 823.6 [M+H] ⁺ .

Step D-Synthesis of Compound 32 To intermediate 15c (62.9 mg, 0.076 mmol) was added 2: 1 anhydrous DCM/TFA (764 μL) at ambient temperature. The reaction mixture was stirred for 1 hour and then cooled to 0°C. MTBE (10 mL) was added to the reaction under stirring, resulting in solid precipitation. The mixture was sonicated and then centrifuged (4000 rpm) to collect insoluble solids. The supernatant was decanted and the MTBE wash (5 mL) and centrifugation were repeated again. The resulting solid was dried in vacuo and then purified by reverse phase chromatography (Isco C18 Aq 30 g Gold column; 0%-40% (ACN+0.1% FA)/(water+0.1% FA) for 12 minutes). The product fractions were collected and freeze-dried to obtain the title compound as a formate salt. LC-MS: m/z 723.2 [M+H] ⁺ . ¹ HNMR (400 MHz, 4:1 D ₂ O/d-DMSO) δ: 7.40-7.25 (m, 2H), 6.84 (d, J=8.6 Hz, 1H), 6.80 (s, 1H), 4.58 (s, 1H), 4.34 (d, J=10.7 Hz, 1H), 3.56-3.42 (m, 1H), 3.16-3.03 (m, 1H), 2.80-2.68 (m, 2H), 2.08-1.98 (m, 5H), 1.73-1.59 (m, 1H), 1.53-1.40 (m, 4H), 1.45 (s, 3H), 1.37 (s, 3H), 1.19 (s, 3H).

Example 19: Preparation of Compound 33

(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3R,5S)-5-(hydroxymethyl)pyrrolidin-3-yl)carbamimidoyl)chroman-2-yl)propanoic acid

Step A - Synthesis of Intermediate 16a To a vial containing a mixture of (2S,4R)-1-Boc-2-hydroxymethyl-4-aminopyrrolidine hydrochloride (108.3 mg, 0.429 mmol) and Intermediate 3c (0.100 g, 0.214 mmol) was added a solution of potassium acetate (0.631 mg, 0.643 mmol) and acetic acid (0.07 mL, 1.286 mmol) in anhydrous MeOH (2 mL). The reaction was heated at 70 °C for 20 minutes, then cooled, diluted with EtOAc (2 mL), and washed with saturated NaHCO ₃ (1 mL). The organic layer was separated, dried over Na ₂ SO ₄ , filtered, and the filtrate concentrated in vacuo to give a foam. The foam was purified by reverse phase HPLC (XSelect CSH Prep C18; 5uM OBD; 30X150mm; 35%-70% (ACN+0.05% TFA)/(water+0.05% TFA) over 8 minutes). Product fractions were collected and dried in Genevac ^TM to give the desired compound. LC-MS: m/z 635.5 [M+H] ⁺ .

Step B - Synthesis of Intermediate 16b To a vial containing Intermediate 16a (0.0817 g, 0.19 mmol) was added 2:1 trifluoroacetic acid/anhydrous dichloromethane (1.4 mL) at ambient temperature. The reaction was stirred for 16.5 hours, then a solution of 4:1 MeOH/toluene (2 mL) was added to the reaction and the mixture was concentrated in vacuo. The resulting residue was azeotroped again with 4:1 MeOH/toluene (2 mL) and then dried in vacuo to give the desired compound. LC-MS: m/z 379.3 [M+H] ⁺ .

Step C - Synthesis of Intermediate 16c To a flask containing Intermediate 16b (0.19 mmol) and Intermediate 4 (0.099 g, 0.213 mmol) was added anhydrous methanol (1.5 mL) at ambient temperature. The reaction was stirred for 3 hours and then concentrated in vacuo. The resulting residue was purified by reverse phase HPLC (XSelect CSH Prep C18; 5 uM OBD; 30X 150 mm; 12%-42% (ACN+0.05% TFA)/(water+0.05% TFA) over 15 minutes) to give the desired compound. LC-MS: m/z 826.0 [M+H] ⁺ .

Step D-Synthesis of Compound 33 To intermediate 16c (87.7 mg, 0.106 mmol) was added 2: 1 anhydrous DCM/TFA (1.1 mL) at ambient temperature. The resulting solution was stirred for 1 hour and then cooled to 0°C. MTBE (3 mL) was added to the reaction with stirring, resulting in solid precipitation. The mixture was sonicated and then centrifuged (4000 rpm) to collect the insoluble solids. The supernatant was decanted and the MTBE wash and centrifugation were repeated again. The resulting solid was dried in vacuo and then purified by reverse phase HPLC (XSelect CSH Prep C18; 5uM OBD; 19X150 mm; 0%-40% (ACN+0.1% FA)/(water+0.1% FA) for 24 minutes; flow rate = 17.0 mL/min.; monitor and collect 254 nM and 215 nM). The product fractions were collected and freeze-dried to give the title compound as a formate salt. LC-MS: m/z 725.5 [M+H] ⁺ . ¹ HNMR (500 MHz, 4:1 D ₂ O/d-DMSO) δ: 7.51 (d, J = 2.2 Hz, 1H), 7.47 (dd, J = 8.6, 2.4 Hz, 1H), 6.96 (d, J = 8.6 Hz, 1H), 6.91 (s, 1H), 4.69 (s, 1H), 4.64 (dt, J = 6.5, 3.3 Hz, 1H), 4.44 (dd, J = 11.3, 2.0 Hz, 1H), 4.10-4.03 (m, 1H), 3.9 2(dd, J＝12.5,3.7Hz,1H),3.83-3.71(m,2H),3.59(dd, J＝13.0,3.4Hz,1H),2.94-2.79(m,2H),2.43-2.27(m,2H),2.14(d, J＝13.7Hz,1H),1.83-1.73(m,1H),1.57(s,3H),1.49(s,3H),1.31(s,3H).

Example 20: Preparation of Compound 34

(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1r,4R)-4-(methylamino)cyclohexyl)-carbamimidoyl)chroman-2-yl)propanoic acid

Step A - Synthesis of Intermediate 17a To a solution of trans-N-Boc-1,4-cyclohexanediamine (0.1761 g, 0.822 mmol) in anhydrous MeOH (4.1 mL) at 0°C was added methyl trifluoroacetate (0.085 mL, 0.838 mmol). After addition, the ice bath was removed and the reaction was stirred at ambient temperature for 3 hours. Hunig's base (0.17 mL, 0.986 mmol) was then added and the reaction was stirred for an additional 16 hours. The reaction mixture was cooled to 0°C and the insoluble solid was collected by filtration, washed with cold ether (2×2 mL), and dried in vacuo to give the desired compound. LC-MS: m/z 333.1 [M+Na] ⁺ .

Step B - Synthesis of Intermediate 17b To a solution of intermediate 17a (0.0472 g, 0.152 mmol) in anhydrous DMF (1 mL) was added NaH (6.08 mg, 0.152 mmol) at ambient temperature. After 1 hour, the reaction was cooled to 0 °C and MeI (8.56 μL, 0.137 mmol) was added dropwise. The reaction was then warmed to ambient temperature, stirred for 15 _hours , then cooled to 0 °C and quenched with water (5 mL). The resulting mixture was partitioned between EtOAc and brine. The organic layer was separated, dried over _Na2SO4 , and concentrated in vacuo. The resulting residue was purified by reverse phase chromatography (Isco C18 26 g column; 0-100% ACN + 0.05% TFA/water + 0.05% TFA). The product fractions were collected, concentrated in vacuo, and the resulting aqueous residue was extracted with EtOAc (2×). The combined organic layers were dried over _Na2SO4 , filtered, and the filtrate was concentrated in vacuo to afford the desired compound. _LC -MS: m/z 347.2 [M+Na] ⁺ .

Step C - Synthesis of Intermediate 17c To a solution of intermediate 17b (60 mg, 0.185 mmol) in anhydrous DCM (1850 μL) at 0°C was added TFA (356 μL, 4.62 mmol). After 1.5 hours, the reaction was concentrated in vacuo and the resulting residue was azeotroped with methanol (2×5 mL). The residue was then dried under high vacuum to give the desired compound. LC-MS: m/z 225.1 [M+H] ⁺ .

Step D - Synthesis of Intermediate 17d To a vial containing a mixture of Intermediate 3c (0.0944 g, 0.202 mmol) and Intermediate 17c (0.041 g, 0.185 mmol) in acetonitrile (1.3 mL) was added acetic acid (0.069 mL, 1.214 mmol) followed by Hunig's base (0.106 mL, 0.607 mmol). The reaction was heated to 70°C for 1 hour. The reaction mixture was then cooled to ambient temperature and purified by reverse phase chromatography (Isco C18 Aq 50 g column; 0-100% ACN + 0.05% TFA/water + 0.05% TFA). The product fractions were collected, concentrated in vacuo, and the resulting aqueous residue was extracted with EtOAc (2×). The combined organic layers were dried over Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo to give the desired compound. LC-MS: m/z 643.5 [M+H] ⁺ .

Step E - Synthesis of Intermediate 17e To a solution of intermediate 17d (79.0 mg, 0.123 mmol) in THF (800 μL)/MeOH (400 μL) was added aqueous LiOH (3M, 82 μL, 0.246 mmol) at ambient temperature. The reaction was stirred at ambient temperature for 1.5 hours and then at 3-4°C for 16 hours. The reaction mixture was then concentrated in vacuo and the resulting residue was purified by reverse phase chromatography (Isco C18 13 g column; 0-100% ACN + 0.05% TFA / water + 0.05% TFA) to give the desired compound. LC-MS: m/z 547.5 [M+H] ⁺ .

Step F - Synthesis of Intermediate 17f To a vial containing Intermediate 17e (0.046 g, 0.084 mmol) was added 2:1 TFA/DCM (0.841 mL) at ambient temperature. The reaction was stirred for 20.5 hours, then 30% toluene/MeOH (5 mL) was added and concentrated in vacuo. The resulting residue was further azeotroped with MeOH (2×5 mL) and dried under high vacuum to give the desired compound. LC-MS: m/z 391.4 [M+H] ⁺ .

Step G - Synthesis of Compound 34 A mixture of Intermediate 17f (32.8 mg, 0.084 mmol), Intermediate 5 (80 wt%, 34.4 mg, 0.076 mmol) and powdered molecular sieves was added at ambient temperature. To a vial of 50% ethyl acetate (325 mesh particles; 0.100 g, dried by heating under high vacuum) was added anhydrous dimethylacetamide (0.34 mL). The reaction mixture was stirred for 19 hours, then the reaction was filtered through a Celite ^™ pad to remove the molecular sieves, and the Celite ^™ pad was washed with MeOH. The filtrate was concentrated in vacuo. The resulting residue was cooled to 0°C and DCM (5 mL) was slowly added with stirring, resulting in precipitation of solids. The solids were collected by centrifugation (4000 rpm). The supernatant was decanted and the insoluble solids were triturated with DCM (3 mL). Repeated centrifugation and decanting of the supernatant gave the crude product as a solid, which was purified by reverse phase HPLC (XSelect CSH Prep C18; 5uM OBD; 50X 250mm; 0%-17% ACN/(water + 0.16% TFA) for 11 minutes; isocratic elution at 17% ACN/(water + 0.16% TFA) for 14 minutes). The product fractions were collected and concentrated in vacuo, and the aqueous layer was loaded directly onto an Amberchrom CG161M column (26 g), washed with 9 CV of (water + 0.1% FA), eluted with 3 CV of 100% (ACN + 0.1% FA), and then 3 CV of 50% (ACN + 0.1% FA) / (water + 0.1% FA). The product fractions were collected and concentrated in vacuo, and the resulting aqueous residue was freeze-dried to give compound 34 as a formate salt. LC-MS: m/z 737.7 [M + H] ⁺ . ¹ H NMR (500 MHz, 4:1D ₂ O/d-DMSO)δ:7.48–7.41(m, 2H),6.99-6.90(m, 2H),4.69(s, 1H),4.49-4.43(m, 1H),3.67–3.60(m, 1H),3.11(t, J＝11.3Hz, 1H),2.91-2.80(m, 2H),2.95-2.77(m, 2H),2.68(s, 3H),2.24-2.18(m, 4H),2.14(d, J＝13.6Hz, 1H),1.80(td, J＝12.9,12.2,5.7Hz,1H),1.58(s, 3H),1.57-1.50(m, 4H),1.49(s, 3H),1.31(s, 3H).

Example 21: Preparation of Compound 35

(S)-2-((R)-6-(N-(4-aminobicyclo[2.2.2]octan-1-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 18a NEt ₃ (0.056 mL, 0.399 mmol) was added to a solution of tert-butyl (4-aminobicyclo [2.2.2] -octan-1-yl) carbamate (72.0 mg, 0.300 mmol) and Intermediate 6c (99 mg, 0.200 mmol) in anhydrous DMF (1.5 mL) at ambient temperature. The reaction was stirred for 30 minutes and then partitioned between EtOAc and saturated aqueous NH ₄ Cl / ice-cold HCl (1 N). The organic layer was separated, washed with brine, dried over Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo. The resulting residue was purified by reverse phase chromatography (Isco C18Aq 30 g column; 0-100% ACN + 0.05% TFA / water + 0.05% TFA). The product fractions were collected, concentrated in vacuo, and the resulting aqueous residue was extracted with EtOAc (2×). The organic layer was washed with brine, dried over Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo to give the desired compound. LC-MS: m/z 675.4 [M+H] ⁺ .

Step B - Synthesis of Intermediate 18b To a solution of _K2CO3 (121 mg, 0.875 mmol) in _methanol (1.5 mL) was added formic acid (0.067 mL, 1.750 mmol). The mixture was stirred at ambient temperature for 10 minutes and then added to a solution of intermediate 18a (118.1 mg, 0.175 mmol) in AcOH (0.90 mL). Pd/C (10 wt%, 74.5 mg, 0.070 mmol) was then added and the resulting mixture was stirred at ambient temperature for 21 hours. The reaction was then filtered through a Celite ^™ pad under _N2 atmosphere and the Celite ^™ pad was washed with MeOH. The filtrate was then concentrated in vacuo and the resulting residue was purified by reverse phase chromatography (Isco C18Aq 30 g column; 0-100% ACN + 0.05% TFA/water + 0.05% TFA). The product fractions were collected and concentrated in vacuo. The resulting aqueous residue was diluted with brine and extracted with EtOAc (2x). The organic layers were combined, dried over _{anhydrous Na2SO4} , filtered, and the filtrate concentrated in vacuo to give the desired compound. LC-MS: m/z 659.5 [M+H] ⁺ .

Step C - Synthesis of Intermediate 18c To a vial containing Intermediate 18b (0.1155 g, 0.175 mmol) was added 1:2 DCM/TFA (1.8 mL) at ambient temperature and the reaction was stirred for 23 hours. 30% toluene/MeOH (5 mL) was added to the reaction and the resulting mixture was concentrated in vacuo. The residue was azeotroped with MeOH (2×5 mL) and then dried under high vacuum to give the desired compound. LC-MS: m/z 403.3 [M+H] ⁺ .

Step D - Synthesis of Compound 35 A mixture of Intermediate 18c (0.175 mmol), Intermediate 5 (0.159 mmol) and powdered molecular sieves was added at ambient temperature. To a vial of 5-nitropropene (325 mesh particles; 50 mg, dried by heating under high vacuum) was added anhydrous dimethylacetamide (0.6 mL). The reaction mixture was stirred for 19 hours, then filtered through a Celite ^™ pad to remove the molecular sieves, and the Celite ^™ pad was washed with MeOH. The filtrate was concentrated in vacuo and the resulting residue was cooled to 0°C. DCM (10 mL) was then slowly added with stirring, resulting in precipitation of solids. The solids were collected by centrifugation (4000 rpm). The supernatant was decanted and the insoluble solids were dried under vacuum. The dried solid was purified by reverse phase HPLC (Select CSH Prep C18; 5uM OBD; 50X 250mm; 0%-16% ACN/(water + 0.16% TFA) for 11 minutes; isocratic elution at 13% ACN/(water + 0.16% TFA) for 14 minutes). The product fractions were collected, concentrated in vacuo, and the aqueous layer was loaded directly onto an Amberchrom CG161M column (26 g), washed with 10 CV of (water + 0.1% FA), eluted with 3 CV of 100% (ACN + 0.1% FA), and then 3 CV of 50% (ACN + 0.1% FA) / (water + 0.1% FA). The product fractions were collected, concentrated in vacuo, and the resulting aqueous residue was freeze-dried to give the title compound as a formate salt. LC-MS: m/z 749.5 [M+H] ⁺ . ¹ H NMR (500 MHz, 4:1 D ₂ O/d-DMSO) δ: 7.37 (s, 1H), 7.36-7.29 (m, 1H), 6.94-6.83 (m, 2H), 4.66 (s, 1H), 4.41 (d, J=11.1 Hz, 1H), 2.88-2.75 (s, 2H), 2.20-2.04 (m, 7H), 1.96-1.88 (m, 6H), 1.80-1.68 (m, 1H), 1.53 (s, 3H), 1.43 (s, 3H), 1.25 (s, 3H).

Example 22: Preparation of Compound 36 (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-(azetidin-3-yl)carbamimidyl)chroman-2-yl)propanoic acid

Step A - Synthesis of Intermediate 19a To a solution of tert-butyl 3-aminoazetidine-1-carboxylate (90 mg, 0.523 mmol) and intermediate 3c (300 mg, 0.505 mmol) in methanol (5 mL) was added acetic acid (0.116 mL, 2.018 mmol) followed by potassium acetate (99 mg, 1.009 mmol) at 23°C. The reaction mixture was stirred at 83°C for 20 minutes and then cooled to room temperature. The reaction mixture was directly purified by silica gel chromatography (Biotage; 12 g Agela Silica Flash Column, 10% MeOH/DCM gradient elution @ 40 mL/min) to give the crude product. The crude product was further purified by reverse phase HPLC (Boston Uni C18 40*150*5um. Conditions: water (0.1% TFA)-ACN; start B 30, end B 60; gradient time (min) 11; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1) to give intermediate 19a. LC-MS (ESI): m/z 591.3 [M+H] ⁺ .

Step B-Synthesis of Intermediate 19b A solution of Intermediate 19a (204 mg, 0.345 mmol) in a 2:1 mixture of DCM:TFA (3 mL) was stirred at 25°C for 0.5 h. The reaction mixture was then dried with a stream of nitrogen to afford Intermediate 19b, which was used in the next step without further purification. LC-MS (ESI): m/z 391.3 [M+H] ⁺ .

Step C - Synthesis of Intermediate 19c A solution of Intermediate 19b (135 mg, 0.346 mmol) and Intermediate 4 (161 mg, 0.346 mmol) in 3 mL MeOH was stirred at 25° C. for 1.5 hours. The reaction mixture was then concentrated in vacuo to afford Intermediate 19c, which was used in the next step without further purification. LC-MS (ESI): m/z 837.7 [M+H] ⁺ .

Step D-Synthesis of Compound 36 A 3:1 mixture solution of intermediate 19c (269 mg, 0.321 mmol) in TFA:DCM (3 mL) was stirred at 25°C for 30 minutes. The reaction mixture was then dried with a stream of nitrogen and the residue was purified by Prep-HPLC (Column Boston Uni C1840*150*5um. Conditions: water (0.1% TFA)-ACN; start B1, end B 31; gradient time (min) 11; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1) to give a crude product. The crude product was further purified by Prep-HPLC (Column YMC-Actus Triart C18 150*30mm*5um. Conditions: water (0.225% FA)-ACN; start B 0, end B 20; gradient time (min) 19; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 3) to give compound 36 in the form of formate salt. LC-MS (ESI): m/z 681.2 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ ): 7.52 (s, 1H), 7.38 (br d, J=8.6 Hz, 1H), 6.73 (s, 1H), 6.70 (br d, J=8.6 Hz, 1H), 4.62-4.51 (m, 1H), 4.44-4.26 (m, 5H), 4.06-3.95 (m, 1H), 2.86-2.61 (m, 2H), 2.06-1.93 (m, 1H), 1.50 (s, 3H), 1.43-1.38 (m, 1H), 1.36 (s, 3H), 1.21 (s, 3H).

Example 23: Preparation of Compounds 37 to 44

Starting from intermediate 3c, compounds 37-44 were prepared using the procedure described in Example 22, Step A to Step D, wherein in Step A, tert-butyl(1-(2-aminoethyl)piperidin-4-yl)carbamate was replaced by a suitable commercially available mono-Boc protected diamine.

Example 24: Preparation of Compounds 45 and 46 (S)-2-((R)-6-(N-((1R,3S)-3-aminocyclopentyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene) ((((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1S,3R)-3-aminocyclopentyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid*

Step A - Synthesis of Intermediate 20a To a stirred mixture of racemic cis-3-((tert-butoxycarbonyl)-amino)cyclopentylammoniumcarboxyformate (448 mg, 1.543 mmol) and Intermediate 3c (600 mg, 1.286 mmol) in methanol (6.0 mL) were added acetic acid (0.294 mL, 5.14 mmol) and potassium acetate (379 mg, 3.86 mmol). The reaction mixture was stirred at 80°C for 10 min, then diluted with _H2O (50 mL), extracted with EtOAc (50 mL x 3), washed with brine (150 mL), and dried over _{anhydrous Na2SO4} . After filtration, the filtrate was concentrated in vacuo and the resulting residue was purified by flash silica gel chromatography (Biotage; 4 g AgelaSilica Flash Column, 0-10% MeOH/DCM gradient elution @ 35 mL/min) to afford Intermediate 20a as a mixture of stereoisomers. LC-MS (ESI): m/z 619.4 [M+H] ⁺ .

Step B-Synthesis of Intermediates 20b-1 and 20b-2 To a solution of intermediate 20a (460 mg, 0.743 mmol) in DCM (10 mL) stirred at 0°C was added _Et3N (0.518 mL, 3.72 mmol) and (Boc) _2O (0.345 mL, 1.487 mmol). The reaction mixture was stirred at 26°C for 2.5 hours, then diluted with saturated aqueous _NH4Cl solution (30 mL), and the mixture was extracted with DCM (30 mL x 3). The combined organic layers were dried over _{anhydrous Na2SO4} , filtered and concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (Biotage; 4 g Agela Silica Flash Column, petroleum ether/EtOAc = 0-60% gradient elution @ 30 mL/min) to afford intermediate 20b as a mixture of stereoisomers. LC-MS (ESI): m/z 719.3 [M+H] ⁺ . The mixture was further separated by SFC to give Intermediate 20b-1 (first eluting isomer) and Intermediate 20b-2 (second eluting isomer). LC-MS (ESI): m/z 719.4 [M+H] ⁺ .

Step C - Synthesis of Intermediate 20c-1 Intermediate 20b-1 (140 mg, 0.195 mmol) was added to a stirred solution of 2:1 DCM/TFA (2.4 mL) at 0° C. The reaction mixture was stirred at 26° C. for 40 minutes, and then the solvent was removed under a stream of N ₂ to give Intermediate 20c-1, which was used in the next reaction without further purification. LC-MS (ESI): m/z 419.3 [M+H] ⁺ .

Step D - Synthesis of Intermediate 20d-1 To a solution of intermediate 20c-1 (82 mg, 0.197 mmol) in MeOH (3.0 mL) was added intermediate 4 (91 mg, 0.197 mmol). The reaction mixture was stirred at 26 °C for 2.5 hours. The reaction mixture was then concentrated under a stream of _N2 to give intermediate 20d-1, which was used in the next step without further purification. LC-MS (ESI): m/z 865.2 [M+H] ⁺ .

Step E - Synthesis of Compounds 45 and 46 A solution of intermediate 20d-1 (170 mg, 0.197 mmol) in 1:2 DCM:TFA (2.5 ml) was stirred at 26°C for 55 minutes. The solvent was then removed under a stream of _N2 and the resulting residue was purified by reverse phase HPLC (column: Boston Uni C18 250*50*5um; conditions: water (0.1% TFA)-ACN; start B1, end B 31; gradient time (min) 11; 100% B retention time (min) 2; flow rate (mL/min) 60). The product fractions were combined and freeze-dried to give compound 45 as its TFA salt. The TFA salt was converted to formate by reverse phase HPLC (column: Welch Xtimate C18 150*25mm*5um; conditions: water (0.225% FA)-ACN; start B 0, end B18; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25) to give compound 45 in the form of formate salt. LC-MS (ESI): m/z 708.9 [M+H] ⁺ . ¹ H NMR (400 MHz, CD ₃ CN+D ₂ O) δ: 7.41-7.34 (m, 2H), 6.86 (d, J=8.6 Hz, 1H), 6.79 (s, 1H), 4.61 (s, 1H), 4.34 (br d, J=10.2 Hz, 1H), 4.10-4.01 (m, 1H), 3.67-3.57 (m, 1H), 2.85-2.69 (m, 2H), 2.67-2.57 (m, 1H), 2.15-1.99 (m, 3H), 1.92-1.57 (m, 4H), 1.48 (s, 3H), 1.42 (s, 3H), 1.24 (s, 3H).

Starting from intermediate 20b-2, compound 46 was prepared using the procedures of Example 24, step C to step E. Compound 46: LC-MS (ESI): m/z 709.1 [M+H]+. ¹ H NMR (400 MHz, CD ₃ CN+D ₂ O) δ: 7.42-7.34 (m, 2H), 6.85 (d, J=8.6 Hz, 1H), 6.79 (s, 1H), 4.61 (s, 1H), 4.34 (br d, J=9.8 Hz, 1H), 4.10-4.01 (m, 1H), 3.63 (quin, J=7.5 Hz, 1H), 2.84-2.68 (m, 2H), 2.68-2.58 (m, 1H), 2.14-2.00 (m, 3H), 1.90-1.63 (m, 4H), 1.49 (s, 3H), 1.42 (s, 3H), 1.24 (s, 3H). *Each compound is a single diastereomer; the stereochemistry of the *marked carbon center is not specified.

Example 25: Preparation of Compounds 47 and 48

(S)-2-((R)-6-(N-((1S,3S)-3-aminocyclopentyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1R,3R)-3-aminocyclopentyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid*

Step A - Synthesis of Intermediates 21a-1 and 21a-2 To a solution of Intermediate 3c (800 mg, 1.715 mmol) in methanol (17 mL) was added trans-3-((tert-butoxycarbonyl)amino)cyclopentylammoniumcarboxyformate (572 mg, 1.972 mmol) and acetic acid (0.393 mL, 6.86 mmol) at 25°C. Potassium acetate (505 mg, 5.14 mmol) was then added. The reaction mixture was stirred at 80°C for 20 minutes (under _N2 atmosphere). The reaction mixture was then concentrated under reduced pressure and the resulting residue was purified by flash silica gel chromatography (ISCO; 12 g Agela _Silica Flash Column, 0-5% _CH2Cl2 /MeOH gradient elution @ 30 mL/min) to give a mixture of Intermediates 21a-1 and 21a-2. LC-MS (ESI): m/z 619.4 [M+H] ⁺ . The mixture of intermediates was further separated by SFC (DAICEL CHIRALCEL OD-H (250 mm*30 mm, 5 um); 0.1% NH ₃ ·H ₂ O/EtOH; start B: 30%; end B: 30%; flow rate (mL/min): 60; injection: 120) to obtain intermediate 21a-1 (first eluting compound) and intermediate 21a-2 (second eluting compound). LC-MS (ESI): m/z 619.3 [M+H] ⁺ .

Step B-Synthesis of Intermediate 21b-1 A solution of intermediate 21a-1 (170 mg, 0.275 mmol) in DCM (0.9 mL) and TFA (1.8 mL) was stirred at 25°C for 0.5 h. The reaction mixture was then concentrated in vacuo to afford intermediate 21b-1, which was used in the next step without further purification. LC-MS (ESI): m/z 418.9 [M+H] ⁺ .

Step C-Synthesis of Intermediate 21c-1 A mixture of Intermediate 21b-1 (115 mg, 0.275 mmol) and Intermediate 4 (115 mg, 0.248 mmol) in methanol (2.8 mL) was stirred at 25° C. for 3 hours. The reaction mixture was then concentrated in vacuo to afford Intermediate 21c-1, which was used in the next step without further purification. LC-MS (ESI): m/z 865.7 [M+H] ⁺ .

Step D-Synthesis of Compounds 47 and 48 To a solution of intermediate 21c-1 (238 mg, 0.275 mmol) in DCM (0.900 mL) was added TFA (1.8 mL). The reaction was stirred at 25°C for 30 minutes, then the solvent was removed with _N2 to give a crude product, which was purified by HPLC (column: Boston Uni C18 40*150*5um; conditions: water (0.1% TFA)-ACN starting B1, ending B 31; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection: 1) to give compound 47 as its TFA salt. The TFA salt was converted to formate by reverse phase HPLC (column: Welch Xtimate C18 150*25mm*5um; conditions: water (0.225% FA)-ACN; start B 0, end B19; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25; injections: 2) to give compound 47 as formate salt. MS (ESI) m/z: 709.4 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.39-7.31 (m, 2H), 6.87 (br d, J=8.6 Hz, 1H), 6.79 (s, 1H), 4.61 (s, 1H), 4.48-4.40 (m, 1H), 4.25-4.14 (m, 1H), 3.80-3.71 (m, 1H), 2.84-2.69 (m, 2H), 2.31-2.17 (m, 3H), 2.14-2.02 (m, 2H), 1.83-1.61 (m, 3H), 1.49 (s, 3H), 1.42 (s, 3H), 1.24 (s, 3H).

According to the procedures in step B to step D of this Example 25, compound 48 was prepared starting from intermediate 21a-2. LC-MS (ESI): m/z 709.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.39-7.29 (m, 2H), 6.90-6.77 (m, 2H), 4.61 (s, 1H), 4.38 (br d, J=11.0 Hz, 1H), 4.23-4.13 (m, 1H), 3.83-3.72 (m, 1H), 2.83-2.69 (m, 2H), 2.31-2.17 (m, 3H), 2.16-2.00 (m, 2H), 1.83-1.63 (m, 3H), 1.49 (s, 3H), 1.41 (s, 3H), 1.23 (s, 3H). *Each compound is a single diastereomer; the stereochemistry of the *marked carbon center is not specified.

Example 26: Preparation of Compounds 49-50

Starting from intermediate 3c, compounds 49-50 were prepared using the methods described in Step A to Step D of Example 25, wherein in Step A, trans-3-((tert-butoxycarbonyl)amino)cyclopentylammoniumcarboxylate was substituted with the appropriate racemic amine:

Example 27: Preparation of Intermediates 22c-1 and 22c-2

Step A - Synthesis of Intermediate 22a To a solution of racemic (3,4-cis)-1-tert-butyl 3-ethyl 4-(benzylamino)piperidine-1,3-dicarboxylate (2 g, 5.52 mmol) in THF (10 mL) stirred at 0°C was added LAH (0.6 g, 15.81 mmol) in portions. The reaction mixture was stirred at 0°C for 0.5 hours and then at 22°C for 15 minutes. The reaction mixture was then quenched by the addition of water (0.6 mL), 10% NaOH (1.2 mL) and water (1.8 mL) in sequence. The resulting mixture was stirred at ambient temperature for 15 minutes and then filtered. The filtrate was concentrated under reduced pressure to give Intermediate 22a, which was used in the next step without further purification. LC-MS (ESI): m/z 321.5 [M+H] ⁺ .

Step B - Synthesis of Intermediate 22b TBS-Cl (1.882 g, 12.48 mmol) was added in one portion to a stirred solution of Intermediate 22a (2 g, 6.24 mmol), imidazole (1.062 g, 15.60 mmol) and DMAP (0.153 g, 1.248 mmol) in DCM (50 mL). The reaction mixture was stirred at 25 °C for 12 h, then diluted with DCM (70 mL), washed with saturated NH ₄ Cl solution (100 mL) and brine (100 mL x 2). The combined organic layers were dried over anhydrous Na ₂ SO ₄ , filtered and concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 20 g Agela Silica Flash Column, 0-28% EtOAc/petroleum ether gradient elution @ 36 mL/min) to afford Intermediate 22b as a racemic mixture. The mixture was further separated by SFC (method: column: DAICELCHIRALCEL OD (250 mm*30 mm, 10 um). Conditions: 0.1% NH ₃ ·H ₂ O/EtOH; start B 15%, end B 15%; flow rate (mL/min) 180; injection: 150) to obtain intermediate 22b-1 (first eluting compound) and intermediate 22b-2 (second eluting compound). Intermediate 22b-1: LC-MS (ESI): m/z 436.1 [M+H] ⁺ . Intermediate 22b-2: LC-MS (ESI): m/z 435.6 [M+H] ⁺ .

Step C - Synthesis of Intermediates 22c-1 and 22c-2 To a solution of intermediate 22b-1 (1 g, 2.301 mmol) in MeOH (30 mL) was added Pd/C (0.184 g, 0.345 mmol). The reaction mixture was stirred at 25 ° C and H ₂ atmosphere (50 psi) for 20 hours. The mixture was then filtered through Celite ^TM and the filtrate was concentrated in vacuo to give intermediate 22c-1, which was used for the next step without further purification. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 3.67-3.58 (m, 2H), 3.58-3.48 (m, 2H), 3.41-3.23 (m, 2H), 1.82 (br s, 1H), 1.73-1.65 (m, 1H), 1.61 (br s, 1H), 1.58-1.51 (m, 1H), 1.46 (s, 9H), 0.90 (s, 9H), 0.06 (s, 6H).

Intermediate 22c-2 was prepared from intermediate 22b-2 using the procedure described in Example 27. ¹ H NMR (400 MHz, CDCl ₃ -d) δ: 3.66-3.52 (m, 4H), 3.39-3.22 (m, 2H), 1.82 (br s, 1H), 1.73-1.61 (m, 2H), 1.53 (dt, J=4.7, 9.2 Hz, 1H), 1.46 (s, 9H), 0.90 (s, 9H), 0.06 (s, 6H).

Example 28: Preparation of Compounds 51 and 52

(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3R,4S)-3-(hydroxymethyl)-piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid and (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3S,4R)-3-(hydroxymethyl)-piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid*

Step A - Synthesis of Intermediate 23a To a stirred mixture of Intermediate 22c-1 (792 mg, 1.839 mmol), potassium acetate (246 mg, 2.508 mmol) and Intermediate 3c (390 mg, 0.836 mmol) in MeOH (15 mL) was added acetic acid (0.191 mL, 3.34 mmol). The reaction was stirred at 80°C for 20 minutes and then the solvent was removed under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 20 g Agela Silica Flash Column, 0-8% MeOH/ _CH2Cl2 gradient elution @ 20 mL/min) to afford Intermediate 23a. _LC -MS (ESI): m/z 763.5 [M+H] ⁺ .

Step B-Synthesis of Intermediate 23b To a solution of intermediate 23a (500 mg, 0.655 mmol) in THF (2 mL) was added a solution of TBAF in THF (1 mL, 0.917 mL, 0.917 mmol). The reaction mixture was stirred at 27 °C for 2 hours. The reaction mixture was then filtered and the filtrate was concentrated in vacuo to give intermediate 23b, which was used in the next step without further purification. LC-MS (ESI): m/z 649.4 [M+H] ⁺ .

Step C - Synthesis of Intermediate 23c To a solution of intermediate 23b (500 mg, 0.771 mmol) in DCM (4 mL) was added TFA (2 mL, 26.0 mmol) dropwise at 0°C. The reaction mixture was stirred at 25°C for 1 hour. The solvent was then removed under reduced pressure to give intermediate 23c, which was used in the next step without further purification. LC-MS (ESI): m/z 449.2 [M+H] ⁺ .

Step D - Synthesis of Intermediate 23d To a solution of intermediate 23c (400 mg, 0.892 mmol) in methanol (8 mL) was added intermediate 4 (331 mg, 0.713 mmol). The reaction was stirred at 25 °C for 2 hours. The solvent was then removed under reduced pressure to give intermediate 23d, which was used in the next step without further purification. LC-MS (ESI): m/z 448.0 [M/2+H] ⁺ .

Step E-Synthesis of Compound 51 TFA (4 mL) was added dropwise to a solution of intermediate 23d (570 mg, 0.637 mmol) in DCM (2 mL) at 0°C, and the resulting solution was stirred at 25°C for 60 minutes. The solvent was then removed under vacuum and the resulting residue was purified by reverse phase HPLC (column: Boston Uni C18 40*150*5um; conditions: water (0.1% TFA)-ACN; start B1, end B 31; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60). The product fractions were combined and freeze-dried to obtain compound 51, which is its TFA salt. The TFA salt was converted to formate by reverse phase HPLC (column: Welch Xtimate C18 150*25mm*5um; condition: water (0.225% FA)-ACN; start B 0, end B 15; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25). The resulting product was further purified by reverse phase HPLC (column: Welch Xtimate C18 150*25mm*5um; condition water (10mM NH ₄ HCO ₃ )-ACN; start B 0, end B 28; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25) to give compound 51 as formate salt. LC-MS (ESI): m/z 739.1 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ ) δ: 7.48-7.40 (m, 2H), 6.96 (d, J=8.6 Hz, 1H), 6.76 (s, 1H), 4.60 (s, 1H), 4.42 (br d, J = 11.0 Hz, 1H), 4.21-4.13 (m, 1H), 3.54-3.42 (m, 2H), 3.34-3.23 (m, 1H), 3.23-3.03 (m, 3H), 2.91-2.71 (m, 2H), 2.28-2.21 (m, 1H), 2.08-1.97 (m, 2H), 1.94-1.83 (m, 1H), 1.65-1.52 (m, 1H), 1.51 (s, 3H), 1.40 (s, 3H), 1.24 (s, 3H).

Starting from intermediate 22c-2, compound 52 was prepared according to the procedures described in step A to step E of example 28. LC-MS (ESI): m/z 739.5 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ ) δ: 7.49-7.38 (m, 2H), 6.97 (d, J=8.6 Hz, 1H), 6.75 (s, 1H), 4.60 (s, 1H), 4.43 (br d, J = 12.1 Hz, 1H), 4.20-4.13 (m, 1H), 3.52-3.44 (m, 2H), 3.35-3.25 (m, 1H), 3.15-2.99 (m, 3H), 2.87-2.71 (m, 2H), 2.27-2.20 (m, 1H), 2.08-1.93 (m, 2H), 1.92-1.81 (m, 1H), 1.61-1.47 (m, 1H), 1.49 (s, 3H), 1.39 (s, 3H), 1.24 (s, 3H). *Each compound is a single diastereomer; the stereochemistry of the *-marked carbon center is not specified.

Example 29: Preparation of Intermediates 24e-1 and 24e-2

Step A-Synthesis of Intermediate 24a To a solution of 1-tert-butyl 2-methyl 4-oxopiperidine-1,2-dicarboxylate (5 g, 19.43 mmol) in THF (10 mL) was added LiBH ₄ (1.693 g, 78 mmol) at 0°C. The reaction mixture was stirred at 25°C for 18 hours, then diluted with water (50 mL) and extracted with ethyl acetate (130 mL×3). The combined organic layers were washed with brine (50 mL), dried over Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo to give a cis/trans mixture of Intermediate 24a, which was used in the next step without further purification.

Step B - Synthesis of Intermediates 24b-1 and 24b-2 To a solution of intermediate 24a (4 g, 10.38 mmol) in DMF (40 mL) was added TEA (2.169 mL, 15.56 mmol), imidazole (0.071 g, 1.038 mmol) and TBDPS-Cl (3.20 mL, 12.45 mmol) in sequence. The reaction was stirred at 20 °C for 16 hours. The resulting mixture was poured into 100 mL of water and then extracted with EtOAc (100 mL x 3). The organic layers were combined, washed with brine (100 mL), dried over anhydrous Na ₂ SO ₄ , filtered and concentrated. The residue was purified by flash silica gel chromatography ( 20g The resulting residue was purified by silica flash column, 10% ethyl acetate/petroleum ether gradient elution @ 45 mL/min) to afford the isolated intermediates 24b-1 and 24b-2.

Intermediate 24b-1: ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.69-7.61 (m, 4H), 7.46-7.33 (m, 6H), 4.24 (br s, 1H), 4.08-4.03 (m, 1H), 3.96 (br d, J=12.2 Hz, 1H), 3.90 (dd, J=5.1, 10.5 Hz, 1H), 3.66 (dd, J=4.3, 10.4 Hz, 1H), 3.46 (br s, 1H), 3.35-3.25 (m, 1H), 1.75-1.57 (m, 2H), 1.44-1.35 (m, 11H), 1.05 (s, 9H).

Intermediate 24b-2: ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.68-7.62 (m, 4H), 7.47-7.37 (m, 6H), 4.47 (br s, 1H), 4.16-4.13 (m, 1H), 3.79 (br s, 1H), 3.64 (br d, J=6.65 Hz, 2H), 2.75 (br t, J=12.52 Hz, 1H), 2.24-2.11 (m, 1H), 1.91-1.78 (m, 1H), 1.47-1.64 (m, 2H), 1.43 (s, 9H), 1.06 (s, 9H).

Step C-Synthesis of Intermediate 24c To a solution of intermediate 24b-1 (3 g, 6.39 mmol) in DCM (10 mL) stirred at 0°C was added TEA (3.56 mL, 25.5 mmol), followed by dropwise addition of methanesulfonyl chloride (2.237 mL, 28.7 mmol). The reaction mixture was stirred at 25°C for 12 hours, then poured into 50 mL of water and extracted with DCM (100 mL×3). The organic layers were combined, washed with brine (70 mL), dried over anhydrous Na ₂ SO ₄ , filtered and concentrated to give intermediate 24c, which was used in the next step without further purification. LC-MS (ESI): m/z 548.1 [M+H] ⁺ .

Step D - Synthesis of Intermediate 24d To a solution of intermediate 24c (3.5 g, 6.39 mmol) in DMF (30 mL) was added sodium azide (1.495 g, 23.00 mmol). The reaction mixture was stirred at 60 °C for 18 hours, then diluted with water (50 mL) and extracted with ethyl acetate (80 mL x 3). The combined organic layers were washed with brine (50 mL), dried over Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo to give intermediate 24d, which was used in the next step without further purification. LC-MS (ESI): m/z 495.2 [M+H] ⁺ .

Step E - Synthesis of Intermediate 24e-1 and Intermediate -24e-2 To a solution of Intermediate 24d (3 g, 6.06 mmol) in MeOH (30 mL) was added 10% Pd/C (0.645 g, 0.606 mmol). The reaction mixture was stirred at 25 °C under 15 psi of _H2 for 12 h. The mixture was then filtered and the filtrate was concentrated in vacuo. The resulting residue was purified by Flash Column Silica-CS (4 g) ( _SiO2 , 50% ethyl acetate in petroleum ether) to give a racemic mixture of enantiomers of Intermediate 24e-1. LC-MS (ESI): m/z 369.2 [M+H-100] ⁺ . The enantiomers of the racemic mixture were separated by SFC (Phenomenex-Cellulose-2 (250 mm*50 mm, 10 um) conditions: 0.1% NH ₃ ·H ₂ O/MeOH; start B 45%, end B 45%; flow rate (mL/min) 200; injection 90). Intermediate 24e-1: LC-MS (ESI): m/z 469.2 [M+H] ⁺ . Intermediate 24e-2: LC-MS (ESI): m/z 469.2 [M+H] ⁺ .

Example 30: Preparation of Compounds 53 and 54 (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((2S,4S)-2-(hydroxymethyl)-piperidin-4-yl)carbamimidoyl)benzodihydropyridine (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((2R,4R)-2-(hydroxymethyl)-piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid*

Step A-Synthesis of Intermediate 25a To a stirred solution of intermediate 3c (500 mg, 1.072 mmol) and intermediate 24e-1 (552 mg, 1.179 mmol) in MeOH (10 mL) at 25°C, acetic acid (0.245 mL, 4.29 mmol) and potassium acetate (316 mg, 3.21 mmol) were added in sequence. The reaction mixture was stirred at 85°C for 30 minutes and then concentrated under reduced pressure to give intermediate 25a, which was used in the next step without further purification. LC-MS (ESI): m/z 887.5 [M+H] ⁺ .

Step B-Synthesis of Intermediate 25b To a solution of intermediate 25a (900 mg, 1.014 mmol) in THF (8 mL) was added tetrabutylammonium fluoride (1.420 mL, 1.420 mmol), stirred at 25°C for 2 hours, then diluted with water (20 mL), extracted with ethyl acetate (80 mL×3). The combined organic layer was washed with brine (20 mL), dried over Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo to give intermediate 25b, which was used in the next step without further purification. LC-MS (ESI): m/z 649.4 [M+H] ⁺ .

Step C - Synthesis of Intermediate 25c To a solution of intermediate 25b (600 mg, 0.925 mmol) in DCM (1 mL) was added TFA (2 mL) at 0°C. The reaction was stirred at 40°C for 1 hour and then concentrated in vacuo to give intermediate 25c, which was used in the next step without further purification. LC-MS (ESI): m/z 393.1 [M+H] ⁺ .

Step D - Synthesis of Intermediate 25d To a solution of intermediate 25c (350 mg, 0.892 mmol) in MeOH (4 mL) was added intermediate 4 (373 mg, 0.803 mmol) at 25°C. The reaction was stirred at 25°C for 2 hours. The reaction was then concentrated under reduced pressure to give intermediate 25d, which was used in the next step without further purification. LC-MS (ESI): m/z 759.1 [M+H-SO ₃ ] ⁺ .

Step E-Synthesis of Compound 53 To a solution of intermediate 25d (700 mg, 0.834 mmol) in DCM (1 mL) was added TFA (2 mL) at 25°C. The reaction was stirred at 25°C for 45 minutes. MTBE (1.5 mL) was then added dropwise at -10-0°C, and the resulting mixture was centrifuged. The collected solid was purified by reverse phase HPLC (column: Boston Uni C18 40*150*5um; condition: water (0.1% TFA)-ACN; start B1, end B 31; gradient time (min) 10; 100% B retention time (min) 2; flow rate 60 mL/min). The product fractions were combined and freeze-dried to obtain compound 53 as a TFA salt. The TFA salt was converted into formate by reverse phase HPLC (column: AgelaDuraShell C18 150*25mm*5um; mobile phase: water (0.225% FA)-acetonitrile; detection wavelength: 220nm), and then freeze-dried to obtain compound 53 as formate. LC-MS (ESI): m/z 739.1 [M+H] ⁺ . ¹ H NMR (400MHz, DMSO-D ₆ ) δ: 7.53-7.41 (m, 2H), 6.97 (d, J=7.4 Hz, 1H), 6.74 (s, 1H), 4.62 (s, 1H), 4.47 (br d, J=11.7 Hz, 1H), 4.07 (br s, 1H), 3.50-3.45(m, 1H), 3.23-3.03(m, 3H), 2.98-2.65(m, 3H), 2.07-1.98(m, 1H), 1.92-1.84(m, 3H), 1.78-1.72(m, 1H), 1.62-1.52(m, 1H), 1.48(s, 3H), 1.39(s, 3H), 1.22(br s, 3H).

Compound 54 was prepared according to the procedure of step A to step E of Example 30 starting from intermediate 24e-2. LC-MS (ESI): m/z 738.9 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-D ₆ )δ: 7.47 (br d, J=16.8 Hz, 2H), 6.95 (br d, J=8.2 Hz, 1H), 6.74 (br s, 1H), 4.59 (br s, 1H), 4.44 (br d, J=10.6 Hz, 1H), 4.09 (br s, 1H), 3.69-3.64 (m, 1H), 3.30-3.04 (m, 3H), 2.98-2.65 (m, 3H), 2.11-1.74 (m, 5H), 1.64-1.52 (m, 1H), 1.49 (br s, 3H), 1.38 (br s, 3H), 1.23 (br s, 3H). *Each compound is a single diastereomer; the stereochemistry of the *-marked carbon center is not specified.

Example 31: Preparation of Compounds 55 and 56

(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((2R,4R)-2-methylpiperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid and (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((2S,4S)-2-methylpiperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid*

Step A - Synthesis of Intermediates 26a-1 and 26a-2 To a solution of cis-tert-butyl 4-amino-2-methylpiperidine-1-carboxylate (755 mg, 3.52 mmol) in THF (18 mL) and water (9 mL) were added sodium carbonate (747 mg, 7.05 mmol) and benzyl chloroformate (0.480 mL, 3.52 mmol) at 0° C. The reaction mixture was stirred at 25° C. for 16 h, then diluted with water (20 mL), extracted with EtOAc (10 mL×4), dried over Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo. The resulting residue was purified by HPLC (column: Boston Uni C1840*150*5um; conditions: water (0.1% TFA)-ACN start B 45, end B 75; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection: 3) to give the product as a racemic mixture (LC-MS (ESI): m/z 349.2[M+H] ⁺ ), which was further purified by chiral SFC (column: DAICEL CHIRALCEL OJ, 250mm*30mm, 10um. Conditions: 0.1% NH ₃ ·H ₂ O/EtOH; start B: 10%, end B: 10%; flow rate (mL/min): 60; injection: 250) to provide intermediate 26a-1 (first eluting enantiomer) and intermediate 26a-2 (second eluting enantiomer), respectively.

Step B - Synthesis of Intermediates 26b-1 and 26b-2 A mixture of intermediate 26a-1 (166.8 mg, 0.479 mmol) and Pd/C (153 mg, 10 wt.%) in MeOH (10 mL) was stirred at 20° C. for 1 hour under a hydrogen atmosphere (15 psi). The reaction mixture was filtered and the filtrate was concentrated in vacuo to give intermediate 26b-1, which was used in the next step without further purification. ¹ H NMR (400 MHz, CD ₃ OD) δ: 3.97-3.87 (m, 1H), 3.74-3.63 (m, 1H), 3.35 (s, 2H), 3.27-3.18 (m, 1H), 2.07-1.92 (m, 1H), 1.89 (s, 1H), 1.46 (s, 9H), 1.44-1.37 (m, 1H), 1.31-1.20 (m, 3H).

Intermediate 26b-2 was prepared from intermediate 26a-2 according to the procedure for preparing 26b-1. ¹ H NMR (400 MHz, CD ₃ OD) δ: 3.98-3.86 (m, 1H), 3.67 (ddd, J=3.5, 6.6, 13.8 Hz, 1H), 3.29-3.18 (m, 1H), 3.17-3.04 (m, 1H), 2.09-1.91 (m, 1H), 1.89 (s, 1H), 1.91-1.88 (m, 1H), 1.46 (s, 9H), 1.42 (br d, J=3.5 Hz, 1H), 1.33-1.21 (m, 3H).

Step C - Synthesis of Intermediate 26c-1 To a solution of intermediate 3c (298 mg, 0.639 mmol) in MeCN (4 mL) was added potassium acetate (188 mg, 1.916 mmol), intermediate 26b-1 (137 mg, 0.639 mmol) and acetic acid (0.146 mL, 2.55 mmol). Under _N2 atmosphere, the reaction mixture was stirred at 80 °C for 10 minutes. The reaction mixture was then filtered and the filtrate was concentrated under reduced pressure. By flash silica gel chromatography ( 20g The resulting residue was purified by Silica Flash Column, 5% CH ₂ Cl ₂ /MeOH gradient elution @30 mL/min) to afford Intermediate 26c-1. LC-MS (ESI): m/z 633.5 [M+H] ⁺ .

Step D-Synthesis of Intermediate 26d-1 To a solution of intermediate 26c-1 (404 mg, 0.638 mmol) in DCM (2 mL) was added TFA (1 mL). The reaction was stirred at 28 °C for 40 minutes and then concentrated under vacuum (15 °C) to give intermediate 26d-1, which was used in the next step without further purification. LC-MS (ESI): m/z: 433.3 [M+H] ⁺ .

Step E - Synthesis of Intermediate 26e-1 To a solution of intermediate 26d-1 (276 mg, 0.638 mmol) in methanol (4 mL) was added intermediate 4 (207 mg, 0.447 mmol) at 20°C. The reaction was stirred at 28°C for 2 hours. The reaction mixture was then concentrated in vacuo to afford intermediate 26e-1, which was used in the next step without further purification. LC-MS (ESI): m/z 879.7 [M+H] ⁺ .

Step F - Synthesis of Compounds 55 and 56 To a solution of intermediate 26e-1 (561 mg, 0.638 mmol) in DCM (1 mL) was slowly added TFA (2.000 mL) at 20°C. The reaction mixture was stirred at 28°C for 50 minutes and then concentrated in vacuo. The resulting residue was purified by reverse phase HPLC (column: Boston Uni C18 40*150*5um; conditions: water (0.1% TFA)-ACN; start B1, end B31; gradient time (min) 10; 100% B retention time 2; flow rate (mL/min) 60; injection 1) to afford compound 55 as a TFA salt. The TFA salt was converted to formate by reverse phase HPLC (column: Welch Xtimate C18 150*25mm*5um; condition water (0.225% FA)-ACN; start B 0, end B18; gradient time (min) 15; 100% retention time (min) 2; flow rate (mL/min) 25; injection 1) to give compound 55 as formate salt. LC-MS (ESI): m/z 723.1 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.36 (s, 1H), 7.33 (br d, J＝9.4 Hz, 1H), 6.91-6.78 (m, 2H), 4.59 (s, 1H), 4.40 (br d, J = 11.7 Hz, 1H), 3.98-3.85 (m, 1H), 3.49-3.40 (m, 1H), 3.36-3.25 (m, 1H), 3.08-2.99 (m, 1H), 2.81-2.70 (m, 2H), 2.33-2.22 (m, 2H), 2.07-1.98 (m, 1H), 1.77-1.65 (m, 2H), 1.62-1.55 (m, 1H), 1.49 (s, 3H), 1.38 (s, 3H), 1.30-1.24 (m, 3H), 1.17 (s, 3H).

Compound 56 was prepared from intermediate 26b-2 according to the procedure of step C to step E of Example 31. LC-MS (ESI): m/z 723.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.43-7.34 (m, 2H), 6.87 (d, J=8.6 Hz, 1H), 6.84 (s, 1H), 4.60 (s, 1H), 4.40 (br d, J = 9.4 Hz, 1H), 3.98-3.86 (m, 1H), 3.53-3.44 (m, 1H), 3.37-3.24 (m, 1H), 3.10-3.01 (m, 1H), 2.86-2.71 (m, 2H), 2.35-2.21 (m, 2H), 2.13-2.02 (m, 1H), 1.85-1.65 (m, 2H), 1.65-1.52 (m, 1H), 1.50 (s, 3H), 1.41 (s, 3H), 1.29 (d, J = 6.7 Hz, 3H), 1.21 (s, 3H). *Each compound is a single diastereomer; the stereochemistry of the *-marked carbon center is not specified.

Example 32: Preparation of Compound 57

(S)-2-((R)-6-(N-((1r,4R)-4-amino-4-methylcyclohexyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A-Synthesis of Intermediate 27a To a solution of intermediate 3c (200 mg, 0.429 mmol) and tert-butyl ((trans)-4-amino-1-methylcyclohexyl)carbamate (117 mg, 0.514 mmol) in MeCN (2.5 mL) at 25°C were added acetic acid (0.098 mL, 1.715 mmol) and potassium acetate (126 mg, 1.286 mmol) in sequence. Then it was diluted with water (10 mL) and extracted with ethyl acetate (10 mL×3). The combined organic layer was washed with brine (10 mL), dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo. The residue was purified by silica gel chromatography eluting with CH ₂ Cl ₂ /MeOH (10:1) to give intermediate 27a. LC-MS (ESI): m/z 647.5 [M+H] ⁺ .

Step B-Synthesis of Intermediate 27b To a solution of intermediate 27a (300 mg, 0.464 mmol) in DCM (1.5 mL) was added aqueous HCl (12 N, 1.5 mL) at 0°C. The reaction was stirred at 25°C for 30 minutes, and then the solvent was removed under a stream of _N2 . The residue was purified by reverse phase HPLC (Boston Uni C18 40*150*5um; conditions: water (0.1% TFA)-ACN; start B1, end B 31; gradient time (min) 11; 100% B retention time (min) 2; flow rate (mL/min) 60; injection: 2) and then freeze-dried to give intermediate 27b. LC-MS (ESI): m/z 391.2 [M+H] ⁺ .

Step C - Synthesis of Compound 57 A solution of intermediate 27b (60 mg, 0.154 mmol) and intermediate 5 (69.8 mg, 0.154 mmol) in DMA (0.6 mL) was stirred at 25 °C for 16 hours. The reaction mixture was then concentrated under a stream of _N2 . The residue was purified by prep-HPLC (Boston Uni C18 40*150*5um; conditions: water (0.1% TFA)-ACN; start B1, end B 31; gradient time (min) 11; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1) and then freeze-dried to give compound 57 as a TFA salt. The TFA salt was dissolved in _H2O (2 mL) and a small amount of DMSO and purified by reverse phase HPLC (Welch Xtimate C18 150*25mm*5um; conditions: water (0.225% FA)-ACN; start B 0, end B1; 8 gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 2), followed by freeze drying to give compound 57 as formate salt. LC-MS (ESI): m/z 737.3 [M+H] ⁺ . ¹ H NMR (400 MHz, CD ₃ CN) δ: 7.44-7.34 (m, 2H), 6.93-6.85 (m, 1H), 6.79 (s, 1H), 4.61 (s, 1H), 4.35-4.43 (m, 1H), 3.62-3.50 (m, 1H), 2.90-2.72 (m, 2H), 2.13-2.04 (m, 1H), 2.01-1.96 (m, 2H), 1.90-1.80 (m, 2H), 1.78-1.57 (m, 5H), 1.51 (s, 3H), 1.42 (s, 3H), 1.34 (s, 3H), 1.25 (s, 3H).

Example 33: Preparation of Compound 58

(S)-2-((R)-6-(N-((1s,4S)-4-amino-4-methylcyclohexyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Compound 58 was prepared according to the procedure of step A to step C of Example 32 by replacing tert-butyl((trans)-4-amino-1-methylcyclohexyl)carbamate in step A with tert-butyl((cis)-4-amino-1-methylcyclohexyl)carbamate. LC-MS (ESI): m/z 759.4 [M+Na] ⁺ . ¹ H NMR (400 MHz, CD ₃ CN) δ: 7.44-7.35 (m, 2H), 6.88 (d, J=8.61 Hz, 1H), 6.78 (s, 1H), 4.62 (s, 1H), 4.38 (br d, J=9.78 Hz, 1H), 3.69-3.55 (m, 1H), 2.89-2.71 (m, 2H), 2.13-2.03 (m, 1H), 2.01-1.95 (m, 2H), 1.91-1.81 (m, 2H), 1.76-1.59 (m, 5H), 1.50 (s, 3H), 1.43 (s, 3H), 1.30 (s, 3H), 1.25 (s, 3H).

Example 34: Preparation of Compound 59

(S)-2-((R)-6-(N-((1s,4S)-4-(aminomethyl)-4-hydroxycyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 28a A solution of Me ₃ SO ⁺ I ^- (6.41 g, 29.1 mmol) in DMSO (30 mL) was treated with sodium hydride (60 wt.% in oil) (1.067 g, 26.7 mmol). The mixture was stirred at 25° C. for 1 hour, then benzyl (4-oxocyclohexyl)carbamate (3.0 g, 12.13 mmol) was added. The resulting mixture was stirred at 25° C. for 16 hours, then diluted with water (80 mL) and extracted with EtOAc (40 mL×3). The organic layers were combined, washed with brine (60 mL), dried over anhydrous Na ₂ SO ₄ , filtered and concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 12 g Agela Silica Flash Column, 0-40% petroleum ether:EtOAc gradient elution @ 30 mL/min) to give Intermediate 28a. ¹ H NMR (CDCl ₃ , 400 MHz) δ: 7.43-7.30 (m, 5H), 5.11 (s, 2H), 4.70 (br s, 1H), 3.66 (br d, J=8.3 Hz, 1H), 2.67 (s, 2H), 2.19-1.72 (m, 4H), 1.67-1.28 (m, 4H).

Step B - Synthesis of intermediate 28b To a solution of intermediate 28a (1.0 g, 3.83 mmol) in MeOH (60 mL) stirred at 25°C was added _{aqueous NH3.H2O} (20 mL, 3.83 mmol, 30 wt.%). The reaction was stirred at 80°C for 16 hours and then concentrated under reduced pressure to afford intermediate 28b which was used in the next step without further purification. ¹ H NMR ( _CDCl3 , 400 MHz) δ: 7.42-7.29 (m, 5H), 5.09 (s, 2H), 4.77 (br d, J=7.8 Hz, 1H), 3.55-3.40 (m, 1H), 2.64-2.55 (m, 2H), 1.71-1.20 (m, 8H).

Step C - Synthesis of Intermediates 28c-1 and 28c-2 To a stirred solution of intermediate 28b (1.05 g, 3.77 mmol) in EtOH (50 mL) at 25°C was added di-tert-butyl dicarbonate (2.190 mL, 9.43 mmol). The reaction was stirred at 25°C for 12 hours. The solvent was then removed under reduced pressure and the resulting residue was purified by flash silica gel chromatography (ISCO; 12 g Agela Silica Flash Column, 0-30% EtOAc/petroleum ether gradient elution @ 30 mL/min) to give a mixture of intermediate 28c-1 and intermediate 28c-2. The mixture was further purified by SFC (column: DAICEL CHIRALCEL OD (250 mm*30 mm, 10 um; condition: 0.1% NH ₃ ·H ₂ O/EtOH; start B 20%, end B 20%; flow rate (mL/min) 200; injection 80) to provide intermediate 28c-1 (first eluting isomer; LC-MS (ESI): m/z 401.3 [M+Na] ⁺ ) and intermediate 28c-2 (second eluting isomer; LC-MS (ESI): m/z 379.3 [M+H] ⁺ ).

Step D - Synthesis of Intermediate 28d-2 To a solution of intermediate 28c-2 (250 mg, 0.661 mmol) in methanol (5 mL) was added Pd/C (70.3 mg, 0.066 mmol, 10 wt.%). The reaction mixture was stirred at 25 °C under _H2 atmosphere (15 psi) for 2 hours and then filtered through Celite ^TM . The filtrate was concentrated under reduced pressure to give intermediate 28d-2, which was used in the next step without further purification. ¹ H NMR ( _CDCl3 , 400 MHz) δ: 5.09 (td, J = 1.6, 3.2 Hz, 2H), 4.78 (s, 2H), 4.43-4.22 (m, 1H), 3.48-3.25 (m, 5H), 3.22 (s, 9H), 3.19-3.11 (m, 2H).

Step E - Synthesis of Intermediate 28e-2 To a stirred mixture of Intermediate 28d-2 (157 mg, 0.643 mmol) and Intermediate 3c (300 mg, 0.643 mmol) in acetonitrile (6 mL) were added acetic acid (0.110 mL, 1.929 mmol) and potassium acetate (189 mg, 1.929 mmol). The reaction mixture was stirred at 80° C. for 20 minutes. The solvent was then removed in vacuo and the resulting residue was purified by preparative TLC (SiO ₂ , DCM:MeOH=10:1) to give Intermediate 28e-2. LC-MS (ESI): m/z 663.4 [M+H] ⁺ .

Step F-Synthesis of Intermediate 28f-2 A mixture of intermediate 28e-2 (160 mg, 0.241 mmol) in aqueous HCl (12 N, 0.4 mL) was stirred at 25°C for 1 hour. The solvent was then removed by a stream of nitrogen and the resulting residue was purified by reverse phase HPLC (column: Boston Uni C18 40*150*5um; conditions: water (0.1% TFA)-ACN; start B1, end B 31; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1) to give intermediate 28f-2. LC-MS (ESI): m/z 407.3 [M+H] ⁺ .

Step G - Synthesis of compound 59 To intermediate 5 (53.6 mg, 0.148 mmol) and To a mixture of molecular sieves (60 mg) and DMA (0.8 mL) was added intermediate 28f-2 (60 mg, 0.148 mmol), and the reaction was stirred at 25 °C for 16 hours. The solvent was then removed by a nitrogen stream, and the resulting residue was purified by reverse phase HPLC (column: Boston Uni C18 40*150*5um; conditions: start B1, end B 31; gradient time (min) 11; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1) to afford compound 59 as a TFA salt. TFA was converted to formate by a second reverse phase HPLC (column: YMC-Actus Triart C18 150*30mm*5um; conditions: water (0.225% FA)-ACN; start B 0, end B18; gradient time (min) 11; 100% retention time (min) 2; flow rate (mL/min) 25; injection 2), and the product fractions were freeze-dried. LC-MS (ESI): m/z 753.2 [M+H] ⁺ . ¹ H NMR (CD ₃ CN+D ₂ O, 400 MHz) δ: 7.44-7.28 (m, 2H), 6.94-6.80 (m, 2H), 4.62 (s, 1H), 4.39 (br d, J=10.2 Hz, 1H), 3.61-3.46 (m, 1H), 2.89 (s, 2H), 2.8 -2.72 (m, 2H), 2.12-1.99 (m, 1H), 1.92-1.82 (m, 2H), 1.80-1.62 (m, 5H), 1.57-1.42 (m, 5H), 1.41 (s, 3H), 1.24 (s, 3H).

Example 35: Preparation of Compound 60

(S)-2-((R)-6-(N-((1r,4R)-4-(aminomethyl)-4-hydroxycyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

According to the procedure of step D to step G of Example 34, compound 60 was prepared starting from intermediate 28c-1. Compound 60: LC-MS (ESI): m/z 753.2 [M+H] ⁺ . ¹ H NMR (CD ₃ CN+D ₂ O, 400 MHz) δ: 7.41-7.30 (m, 2H), 6.87 (br d, J=9.0 Hz, 1H), 6.81 (s, 1H), 4.60 (s, 1H), 4.38 (br d, J=12.5 Hz, 1H), 3.75-3.65 (m, 1H), 3.03 (s, 2H), 2.85-2.71 (m, 2H), 2.12 -1.95 (m, 2H), 1.84-1.52 (m, 8H), 1.49 (s, 3H), 1.41 (s, 3H), 1.22 (s, 3H).

Example 36: Preparation of Intermediates 29a-1 and 29a-2

Step A - Synthesis of Intermediates 29a-1 and 29a-2 To a solution of tert-butyl (6-aminospiro-[3.3]hept-2-yl)carbamate (1.055 g, 4.66 mmol) in THF (30 mL) and water (15 mL) was added sodium carbonate (0.988 g, 9.32 mmol) and benzyl chloroformate (0.636 mL, 4.66 mmol). The reaction was stirred at 25 °C for 16 hours, then filtered and the filtrate concentrated in vacuo. The residue was purified by flash silica gel chromatography ( 12g The resulting residue was purified by Silica Flash Column, 0-15% petroleum ether/EtOAc gradient elution @30 mL/min) to give a racemic mixture of intermediate 29a-1 and intermediate 29a-2. The racemic mixture was separated by SFC (column: DAICEL CHIRALCEL OJ 250 mm*30 mm, 10 um; condition: 0.1% NH ₃ ·H ₂ O/EtOH; start B: 20%, end B: 20%; flow rate (mL/min): 70; injection: 100) to separately provide intermediate 29a-1 (first eluting isomer, LC-MS (ESI): m/z 383.2 [M+Na] ⁺ ) and intermediate 29a-2 (second eluting isomer, LC-MS (ESI): m/z 383.2 [M+Na] ⁺ ).

Example 37: Preparation of Compounds 61 and 62

(S)-2-((R)-6-(N-((2R,4r,6R)-6-aminospiro[3.3]hept-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((2S,4s,6S)-6-aminospiro[3.3]hept-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Compounds 61 and 62 were prepared according to the procedure of Step D to Step G of Example 34 by replacing Intermediate 29a-1 or Intermediate 29a-2 in Step D with Intermediate 28c-2, respectively. Compound 61: LC-MS (ESI): m/z 735.5 [M+H] ⁺ . ¹ HNMR (D ₂ O+CD ₃ CN, 400 MHz) δ: 7.43-7.29 (m, 2H), 6.92-6.79 (m, 2H), 4.58 (s, 1H), 4.39 (br d, J = 9.8 Hz, 1H), 4.09-3.97 (m, 1H), 3.72-3.61 (m, 1H), 2.86-2.70 (m, 2H), 2.62-2.55 (m, 1H), 2.52-2.40 (m, 2H), 2.38-2.28 (m, 1H), 2.23-2.10 (m, 4H), 2.09-2.03 (m, 1H), 1.79-1.64 (m, 1H), 1.49 (s, 3H), 1.41 (s, 3H), 1.22 (s, 3H). Compound 62: LC-MS (ESI): m/z 735.3 [M+H] ⁺ . ¹ HNMR (D ₂ O+CD ₃ CN, 400 MHz) δ: 7.39-7.31 (m, 2H), 6.89-6.82 (m, 2H), 4.59 (s, 1H), 4.41 (br d, J = 9.0 Hz, 1H), 4.08-4.01 (m, 1H), 3.72-3.62 (m, 1H), 2.86-2.68 (m, 2H), 2.64-2.55 (m, 1H), 2.50-2.38 (m, 2H), 2.37-2.26 (m, 1H), 2.22-2.11 (m, 4H), 2.08-2.02 (m, 1H), 1.79-1.62 (m, 1H), 1.50 (s, 3H), 1.40 (s, 3H), 1.21 (s, 3H).

Example 38: Preparation of Intermediates 30e-1 and 30e-2

Step A - Synthesis of Intermediate 30a To a suspension of NaH (1.051 g, 26.3 mmol, 60% oil solution) in THF (120 mL) at 0°C was added methyl 2-(dimethoxyphosphoryl)acetate (4.42 g, 24.26 mmol). The reaction mixture was stirred at 0°C for 20 minutes and benzyl(4-oxocyclohexyl)-carbamate (5 g, 20.22 mmol) was added. The reaction mixture was warmed to ambient temperature and stirred for 1 hour and then concentrated in vacuo. Saturated aqueous NH ₄ Cl solution (80 mL) was added to the resulting residue and the mixture was extracted with MTBE (150 mL). The combined organic layers were concentrated to give Intermediate 30a which was used in the next step without further purification. LC-MS (ESI): m/z 304.1 [M+H] ⁺ .

Step B - Synthesis of intermediate 30b A solution of intermediate 30a (2 g, 6.59 mmol) in NH ₃ /MeOH (7 mmol, 47.1 mL, 330 mmol) was stirred in a sealed tube at 100° C. for 16 hours. The solvent was then removed under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 12 g Agela Silica Flash Column, 0-8% CH ₂ Cl ₂ /MeOH (gradient) elution @ 20 mL/min) to afford intermediate 30b. LC-MS (ESI): m/z 321.2 [M+H] ⁺ .

Step C - Synthesis of Intermediate 30c To a mixture of intermediate 30b (4.9 g, 15.29 mmol) and (Boc)2O (3.55 mL, 15.29 mmol) in THF (50 mL) and water (50.0 mL) was added DIEA (2.67 mL, 15.29 mmol). The reaction was heated at 85°C for 4 hours, then cooled to ambient temperature and extracted with EtOAc (3×50 mL). The combined organic layers were washed with brine (100 mL), dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 40 g Agela Silica Flash Column, 25% petroleum ether/EtOAc gradient elution @ 40 mL/min) to afford intermediate 30c. LC-MS (ESI): m/z 421.4 [M+H] ⁺ .

Step D - Synthesis of Intermediate 30d To a solution of intermediate 30c (2.6 g, 6.18 mmol) in THF (35 mL) was added LiBH ₄ (0.606 g, 27.8 mmol) at 0°C. The reaction mixture was stirred at 20°C for 16 hours, then quenched with saturated aqueous NH ₄ Cl solution (20 mL), extracted with EtOAc (50 mL), dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 20 g Agela Silica Flash Column, 0-35% petroleum ether/EtOAc (gradient) elution @ 30 mL/min) to afford intermediate 30d. LC-MS (ESI): m/z 293.2 [M-Boc+H] ⁺ .

Step E - Synthesis of Intermediates 30e-1 and 30e-2 A mixture of intermediate 30d (1 g, 2.55 mmol), _Ag2O (11.81 g, 51.0 mmol) and MeI (6.37 mL, 102 mmol) in MeCN (100 mL) was stirred at 25°C under nitrogen in the dark for 36 hours, then the reaction mixture was filtered and the filtrate was concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (ISCO; 12 g Agela Silica Flash Column, 0-30% EtOAc/petroleum ether gradient elution @ 30 mL/min) to give a mixture of intermediates 30e-1 and 30e-2. The intermediate mixture was further separated by reverse phase HPLC (column: Phenomenex Synergi C18 150*30mm*4um; conditions: water (0.1% TFA)-ACN; start B 51, end B 81; gradient time (min) 11; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 9) to provide intermediate 30e-1 and intermediate 30e-2 separately.

Intermediate 30e-1: ¹ H NMR (400 MHz, CD ₃ OD) δ: 7.36-7.26 (m, 5H), 5.05 (s, 2H), 3.44 (t, J=6.8 Hz, 2H), 3.37 (br t, J=11.5 Hz, 1H), 3.29 (s, 3H), 2.24 (br d, J=12.5 Hz, 2H), 1.89 (br t, J=6.7 Hz, 2H), 1.70 (br d, J=10.0 Hz, 2H), 1.43 (s, 10H), 1.40-1.37 (m, 1H), 1.33-1.25 (m, 2H).

Intermediate 30e-2: ¹ H NMR (400 MHz, CD ₃ OD) δ: 7.37-7.26 (m, 5H), 5.06 (s, 2H), 3.54 (br s, 1H), 3.44 (t, J=6.7 Hz, 2H), 3.30 (s, 3H), 2.01 (br t, J=6.7 Hz, 2H), 1.81-1.71 (m, 5H), 1.51-1.45 (m, 2H), 1.42 (s, 10H).

Example 39: Preparation of Compounds 63 and 64

(S)-2-((R)-6-(N-((1s,4S)-4-amino-4-(2-methoxyethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(2-methoxyethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

According to the procedure of step D to step G of Example 34, compounds 63 and 64 were prepared starting from intermediates 30e-1 and 30e-2, respectively.

Compound 63: LC-MS (ESI): m/z 781.1 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ ) δ: 7.47-7.37 (m, 2H), 6.88 (d, J=8.2 Hz, 1H), 6.75 (s, 1H), 4.58 (s, 1H), 4.34 (br d, J=11.7 Hz, 1H), 3.69-3.56 (m, 1H), 3.50-3.41 (m, 2H), 3.22 (s, 3H), 2.84-2.68 (m, 2H), 2.03-1.74 (m, 8H), 1.73-1.53 (m, 4H), 1.44 (s, 3H), 1.38 (s, 3H), 1.22 (s, 3H).

Compound 64: LC-MS (ESI): m/z 781.1 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ ) δ: 7.48-7.35 (m, 2H), 6.98 (d, J=8.6 Hz, 1H), 6.75 (s, 1H), 4.59 (s, 1H), 4.48 (br d, J=12.1 Hz, 1H), 3.54-3.40 (m, 3H), 3.25 (s, 3H), 2.90-2.68 (m, 2H), 2.11-2.01 (m, 1H), 1.95-1.75 (m, 6H), 1.71-1.50 (m, 5H), 1.50 (s, 3H), 1.39 (s, 3H), 1.23 (s, 3H).

Example 40: Preparation of Intermediates 31-1 and 31-2

The stereoisomers of intermediate 30d (0.9 g, 2.293 mmol) were separated by SFC (DAICEL CHIRALPAK AD (250 mm*50 mm, 10 um); conditions: 0.1% NH ₃ ·H ₂ O/IPA; start B 35, end B 35; flow rate (mL/min) 60; injection 80) to give intermediate 31-1 (LC-MS (ESI): m/z 415.4 [M+Na] ⁺ ) and intermediate 31-2 (LC-MS (ESI): m/z 415.4 [M+Na] ⁺ ), respectively.

Example 41: Preparation of Compounds 65 and 66

(S)-2-((R)-6-(N-((1s,4S)-4-amino-4-(2-hydroxyethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(2-hydroxyethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

According to the procedure of step D to step G of Example 34, compounds 65 and 66 were prepared starting from intermediate 31-1 and intermediate 31-2, respectively.

Compound 65: LC-MS (ESI): m/z 767.3 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ ) δ: 7.48-7.39 (m, 2H), 6.88 (br d, J=8.2 Hz, 1H), 6.77 (s, 1H), 4.62 (s, 1H), 4.38 (br d, J=10.6 Hz, 1H), 3.68 (br s, 1H), 3.51-3.49 (m, 2H), 2.74-2.58 (m, 2H), 2.22-2.04 (m, 1H), 1.95-1.53 (m, 10H), 1.39 (s, 3H), 1.34 (br s, 3H), 1.23 (s, 3H), 1.07-0.83 (m, 1H).

Compound 66: LC-MS (ESI): m/z 767.3 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ ) δ: 7.49-7.36 (m, 2H), 6.92 (d, J=8.2 Hz, 1H), 6.76 (s, 1H), 4.57 (s, 1H), 4.45-4.35 (m, 1H), 3.80-3.75 (m, 1H), 3.65-3.53 (m, 2H), 2.96-2.74 (m, 2H), 2.09-2.01 (m, 1H), 1.93-1.78 (m, 6H), 1.68-1.46 (m, 7H), 1.38 (s, 3H), 1.22 (s, 3H), 1.13 (t, J=7.2 Hz, 1H).

Example 42: Preparation of Intermediates 32b-1 and 32b-2

Step A - Synthesis of Intermediate 32a To a mixture of tert-butyl (3-oxocyclobutyl) carbamate (1.5 g, 8.10 mmol) and acetic acid (0.844 mL) in ethanol (9.71 mL) stirred at 0°C was added methylamine (33% in ethanol) (9.71 mL, 81 mmol). The reaction was stirred at 0°C for 1.5 hours, then warmed to 20°C and stirred for an additional 2 hours. The mixture was cooled to -70°C, and LiBH ₄ (0.390 g, 17.90 mmol) was added in portions. The reaction was stirred at -70°C for 1 hour, then warmed to 20°C and stirred for 16 hours. The reaction mixture was then quenched with water (40 mL) and concentrated in vacuo. The resulting aqueous mixture was acidified to pH 2 with concentrated hydrochloric acid and washed with ethyl acetate (2×40 mL). The aqueous layer was then basified to pH 9-10 with 10% sodium hydroxide and extracted with dichloromethane (3×50 mL). The combined organic layers were washed with brine (60 mL), dried over anhydrous sodium sulfate, and concentrated in vacuo to afford intermediate 32a, which was used in the next step without further purification. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 4.63 (br s, 1H), 3.82 (br d, J=7.3 Hz, 1H), 2.96-2.80 (m, 1H), 2.74-2.61 (m, 2H), 2.33 (s, 3H), 2.20-2.00 (m, 1H), 1.50 (br d, J=10.8 Hz, 2H), 1.43 (s, 9H).

Step B - Synthesis of Intermediates 32b-1 and 32b-2 To a stirred solution of intermediate 32a (1.3 g, 6.49 mmol) in THF (40 mL) and water (20.00 mL) at 0°C were added _Na2CO3 ( _1.376 g, 12.98 mmol) and benzyl chloroformate (1.205 mL, 8.44 mmol). The reaction was stirred at 20°C for 16 hours. The reaction was then diluted with water (50 mL), extracted with EtOAc (50 mL x 3), dried over _{anhydrous Na2SO4} , filtered and concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (ISCO; 12 g Agela Silica Flash Column, 0-30% EtOAc/petroleum ether (gradient) elution @ 30 mL/min) to give the desired cis-, trans-stereoisomer mixture. The mixture was separated by SFC (column: DAICEL CHIRALPAK AD-H 250 mm*30 mm, 5 um; condition: 0.1% NH ₃ ·H ₂ O/EtOH; start B25, end B 25; flow rate (mL/min) 60; injection 180) to give intermediate 32b-1 (first eluting component, LC-MS (ESI): m/z 335.4 [M+H] ⁺ ) and intermediate 32b-2 (second eluting component, LC-MS (ESI): m/z 235.3 [M-Boc] ⁺ ).

Example 43: Preparation of Intermediates 33c-1 and 33c-2

Step A-Synthesis of Intermediate 33a-1 A solution of intermediate 32b-1 (400 mg, 1.196 mmol) in HCl/EtOAc (400 M, 8 mL) was stirred at 20°C for 0.5 h. The reaction mixture was then concentrated under reduced pressure to afford intermediate 33a-1, which was used in the next step without further purification. LC-MS (ESI): m/z 235.1 [M+H] ⁺ .

Step B - Synthesis of Intermediate 33b-1 To a solution of intermediate 33a-1 (261 mg, 1.114 mmol) in MeCN (8 mL) at 25°C were added intermediate 3c (400 mg, 0.857 mmol), acetic acid (0.196 mL, 3.43 mmol) and potassium acetate (252 mg, 2.57 mmol) in sequence. The reaction mixture was stirred at 80°C for 30 minutes under _N2 atmosphere and then filtered. The filtrate was concentrated in vacuo. The resulting residue was purified by reverse phase HPLC (Biotage; 20 g Agela C18 column, 0-40% MeCN/ _H2O (0.5% TFA) gradient elution @ 50 mL/min) to afford intermediate 33b-1. LC-MS (ESI): m/z 653.7 [M+H] ⁺ .

Step C - Synthesis of Intermediates 33c-1 and 33c-2 A mixture of intermediate 33b-1 (365 mg, 0.559 mmol) and Pd/C (179 mg, 0.168 mmol, 10 wt.%) in EtOAc ( ₈ mL) was stirred at 25° C. under H 2 (15 psi) for 5 hours. The reaction mixture was then filtered and the filtrate was concentrated in vacuo to afford intermediate 33c-1, which was used in the next step without further purification. LC-MS (ESI): m/z 519.5 [M+H] ⁺ .

Intermediate 33c-2 was prepared from Intermediate 32b-2 using the procedure of Step A to Step C of Example 43. LC-MS (ESI): m/z 519.5 [M+H] ⁺ .

Example 44: Preparation of Compounds 67 and 68

(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-(trans-3-(methylamino)cyclobutyl)-carbamimidoyl)chroman-2-yl)propanoic acid and (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-(cis-3-(methylamino)cyclobutyl)-carbamimidoyl)chroman-2-yl)propanoic acid

Following the procedure of step B to step C of Example 32, compounds 67 and 68 were prepared starting from intermediate 33c-1 and intermediate 33c-2, respectively.

Compound 67: LC-MS (ESI): m/z 709.1 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.45-7.31 (m, 2H), 6.96-6.69 (m, 2H), 4.60 (s, 1H), 4.36 (br d, J=11.3 Hz, 1H), 4.07-3.88 (m, 1H), 3.59-3.44 (m, 1H), 2.98-2.67 (m, 4H), 2.54 (s, 3H), 2.37-2.23 (m, 2H), 2.09-2.00 (m, 1H), 1.74-1.59 (m, 1H), 1.48 (s, 3H), 1.41 (s, 3H), 1.23 (s, 3H).

Compound 68: LC-MS (ESI): m/z 709.1 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.45-7.29 (m, 2H), 6.90-6.78 (m, 2H), 4.60 (s, 1H), 4.44-4.34 (m, 1H), 4.30-4.16 (m, 1H), 3.90-3.77 (m, 1H), 2.90-2.48 (m, 9H), 2.09-2.00 (m, 1H), 1.77-1.60 (m, 1H), 1.50 (s, 3H), 1.41 (s, 3H), 1.23 (s, 3H).

Example 45: Preparation of Intermediates 34g-1 and 34g-2

Step A - Synthesis of Intermediate 34a To a stirred solution of 1-((((9H-fluoren-9-yl)methoxy)-carbonyl)amino)-4-oxocyclohexane-1-carboxylic acid (5 g, 13.18 mmol) in DCM (40 mL) and MeOH (10 mL) at 0°C was added (trimethylsilyl)diazomethane (2M in hexanes) (13.18 mL, 26.4 mmol) dropwise. The reaction was stirred at 25°C for 12 h, then cooled to 0°C and AcOH (1 mL) was added dropwise. The reaction mixture was diluted with DCM (80 mL), washed sequentially with saturated aqueous _NaHCO3 solution (50 mL) and brine (30 mL), dried over _{anhydrous Na2SO4} and filtered. The filtrate was concentrated in vacuo to give Intermediate 34a, which was used in the next reaction without further purification. LC-MS (ESI): m/z 394.1 [M+H] ⁺ .

Step B - Synthesis of Intermediate 34b To a stirred solution of intermediate 34a (3 g, 7.63 mmol) and ammonium acetate (5.88 g, 76 mmol) in MeOH (200 mL) at 15°C was added sodium triacetoxyborohydride (8.08 g, 38.1 mmol) in one portion. The reaction mixture was stirred at 25°C for 12 h and then quenched by the addition of saturated aqueous _NH4Cl solution (100 mL). The mixture was extracted with DCM (200 mL). The organic phase was separated, dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 40 g Agela Silica Flash Column, 0-10% MeOH/ _CH2Cl2 gradient elution @ ₃₀ mL/min) to afford intermediate 34b. LC-MS (ESI): m/z 395.2 [M+H] ⁺ .

Step C - Synthesis of Intermediate 34c A solution of Intermediate 34b (1.7 g, 4.31 mmol) and (Boc) ₂ O (5.00 mL, 21.55 mmol) in CHCl ₃ (40 mL) was stirred at 80° C. for 16 h. The reaction was cooled to room temperature and then purified by flash silica gel chromatography (ISCO; 20 g Agela Silica Flash Column, 35% petroleum ether/EtOAc gradient elution @ 30 mL/min) to afford Intermediate 34c. LC-MS (ESI): m/z 507.3 [M+Na] ⁺ .

Step D - Synthesis of Intermediates 34d-1 and 34d-2 To a solution of intermediate 34c (1.3 g, 2.63 mmol) in THF (20 mL) stirred at 0°C was added LiBH ₄ (0.258 g, 11.83 mmol). The reaction mixture was stirred at 20°C for 16 hours and then quenched with saturated aqueous NH ₄ Cl solution (20 mL). The resulting mixture was extracted with EtOAc (50 mL). The organic phase was separated, dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 12 g Agela Silica Flash Column, 0-35% petroleum ether/EtOAc gradient elution @ 30 mL/min) to give intermediate 34d-1 (first eluting stereoisomer) and intermediate 34d-2 (second eluting stereoisomer). LC-MS (ESI): m/z 467.2 [M+H] ⁺ .

Intermediate 34d-1: ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.77 (d, J=7.4 Hz, 2H), 7.57 (d, J=7.4 Hz, 2H), 7.44-7.38 (m, 2H), 7.35-7.30 (m, 2H), 4.45 (br s, 3H), 3.71 (br s, 2H), 3.54 (br s, 1H), 1.93 (br s, 2H), 1.81 (br s, 1H), 1.49 (br s, 1H), 1.44 (s, 11H), 1.37 (br s, 2H).

Intermediate 34d-2: ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.79 (d, J=7.4 Hz, 2H), 7.60 (d, J=7.4 Hz, 2H), 7.43 (t, J=7.6 Hz, 2H), 7.38-7.32 (m, 2H), 4.52 (br s, 2H), 4.39 (br s, 1H), 3.58 (br s, 3H), 2.02 (br s, 1H), 1.86 (br s, 3H), 1.47-1.45 (m, 11H), 1.40-1.12 (m, 2H).

Step E - Synthesis of Intermediate 34e-1 A solution of intermediate 34d-1 (200 mg, 0.429 mmol) in HCl/MeOH (4 M, 2 mL) was stirred at 25° C. for 0.5 h. The reaction mixture was then concentrated in vacuo to afford intermediate 34e-1, which was used in the next step without further purification. LC-MS (ESI): m/z 367.1 [M+H] ⁺ .

Step F - Synthesis of Intermediate 34f-1 Potassium acetate (88 mg, 0.900 mmol) was added to a stirred mixture of Intermediate 34e-1 (132 mg, 0.360 mmol), Intermediate 3c (140 mg, 0.300 mmol) and acetic acid (0.069 mL, 1.200 mmol) in MeCN (4 mL). The reaction was stirred at 80 °C for 30 minutes, then filtered and the filtrate was concentrated under reduced pressure. The resulting residue was purified by preparative TLC plate (CH ₂ Cl ₂ /MeOH=10:1) to give Intermediate 34f-1. LC-MS (ESI): m/z 785.8 [M+H] ⁺ .

Step G-Synthesis of Intermediates 34g-1 and 34g-2 To a solution of intermediate 34f-1 (120 mg, 0.153 mmol) in DMF (2 mL) was added piperidine (15.62 mg, 0.183 mmol). The reaction was stirred at 25 °C for 0.5 h and then concentrated in vacuo to afford intermediate 34g-1, which was used in the next step without further purification. LC-MS (ESI): m/z 563.5 [M+H] ⁺ .

Intermediate 34g-2 was prepared from Intermediate 34d-2 according to the procedure of step E to step G of Example 45. LC-MS (ESI): m/z 563.3 [M+H] ⁺ .

Example 46: Preparation of Compounds 69 and 70

(S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(hydroxymethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1s,4S)-4-amino-4-(hydroxymethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Following the procedure of step F to step G of Example 34, compounds 69 and 70 were prepared starting from intermediate 34g-1 and intermediate 34g-2, respectively.

Compound 69: LC-MS (ESI): m/z 753.2 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ ) δ: 7.45-7.32 (m, 2H), 6.91 (d, J=8.6 Hz, 1H), 6.74 (s, 1H), 4.58 (s, 1H), 4.39 (br d, J=11.7 Hz, 1H), 3.60-3.45 (m, 3H), 2.85-2.66 (m, 2H), 2.09-1.99 (m, 1H), 1.92-1.71 (m, 4H), 1.63-1.40 (m, 8H), 1.38 (s, 3H), 1.23 (s, 3H).

Compound 70: LC-MS (ESI): m/z 753.4 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ ) δ: 7.49-7.38 (m, 2H), 6.91 (br d, J=9.4 Hz, 1H), 6.75 (s, 1H), 4.61 (s, 1H), 4.39 (br d, J=11.7 Hz, 1H), 3.48-3.34 (m, 3H), 2.84-2.65 (m, 2H), 2.05-1.44 (m, 10H), 1.38 (apparent s, 6H), 1.23 (s, 3H).

Example 47: Preparation of Intermediates 35b-1 and 35b-2

Step A - Synthesis of Intermediate 35a-1 To a solution of tert-butyl ((1r, 4r)-4-amino-1-methylcyclohexyl)carbamate (100 mg, 0.438 mmol) in THF (1.8 mL) and water (0.6 mL) at 0°C was added sodium carbonate (139 mg, 1.314 mmol) and benzyl chloroformate (0.072 mL, 0.526 mmol). The reaction was stirred at 20°C for 16 hours and then diluted with water (10 mL). The resulting mixture was extracted with EtOAc (3×20 mL). The combined organic fractions were washed with brine (10 mL), dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by preparative TLC plates (eluted with 3:1 petroleum ether/EtOAc, SiO ₂ ) to give Intermediate 35a-1. LC-MS (ESI): m/z 385.3 [M+Na] ⁺ . ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.35-7.39 (m, 5H), 5.07 (s, 2H), 4.74 (br s, 1H), 4.41 (br s, 1H), 3.68-3.54 (m, 1H), 1.93-1.77 (m, 2H), 1.77-1.58 (m, 4H), 1.43 (s, 9H), 1.46-1.34 (m, 2H), 1.32 (s, 3H).

Step B - Synthesis of Intermediates 35b-1 and 35b-2 A solution of intermediate 35a-1 (500 mg, 1.379 mmol) in HCl/EtOAc (4M, 10 mL) was stirred at 20°C for 2 hours. The reaction mixture was then concentrated in vacuo to afford intermediate 35b-1, which was used in subsequent reactions without further purification. ¹ H NMR (400 MHz, CD ₃ OD) δ: 7.44-7.19 (m, 5H), 5.07 (s, 2H), 3.51-3.34 (m, 1H), 1.94-1.80 (m, 4H), 1.75-1.65 (m, 2H), 1.56-1.44 (m, 2H), 1.37 (s, 3H).

Intermediate 35b-2 was prepared from tert-butyl ((1s,4s)-4-amino-1-methylcyclohexyl)-carbamate according to the procedures in step A and step B of Example 47. LC-MS (ESI): m/z 263.2 [M+H] ⁺ .

Example 48: Preparation of Compound 71

(S)-2-((R)-6-(N-((1r,4R)-4-amino-1-methylcyclohexyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 36a To a solution of intermediate 35b-1 (156 mg, 0.595 mmol) in DMF (6 mL) was added TEA (0.237 mL, 1.699 mmol) and intermediate 6c (400 mg, 0.849 mmol). The reaction was stirred at 25 °C for 2 hours, then the reaction mixture was diluted with ice water (20 mL) and extracted with ethyl acetate (40 mL x 2). The combined organic layers were washed with brine (20 mL), dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo to give intermediate 36a, which was used in the next step without further purification. LC-MS (ESI): m/z 697.2 [M+H] ⁺ .

Step B - Synthesis of Intermediate 36b To a solution of K ₂ CO ₃ (297 mg, 2.153 mmol) in methanol (2.8 mL) was added formic acid (198 mg, 4.31 mmol) under N ₂ at 20°C. The reaction mixture was stirred at 20°C for 10 min and then added to a solution of intermediate 36a (300 mg, 0.431 mmol) in acetic acid (1.8 mL) and acetic anhydride (48.3 mg, 0.474 mmol). Pd/C (183 mg, 0.172 mmol, 10% wt.) was then added and the reaction was stirred at 25°C for 12 h. The reaction mixture was then filtered and the filtrate was concentrated under reduced pressure to give intermediate 36b. It was used in the next step without further purification. LC-MS (ESI): m/z 681.6 [M+H] ⁺ .

Step C - Synthesis of Intermediate 36c To a solution of intermediate 36b (400 mg, 0.588 mmol) in ethyl acetate (20 mL) was added Pd/C (31.3 mg, 0.294 mmol, 10 wt.%). The reaction mixture was stirred at 25 °C under _H2 atmosphere for 1 hour. The reaction mixture was then filtered and the filtrate was concentrated in vacuo to give intermediate 36c, which was used in the next step without further purification. LC-MS (ESI): m/z 547.4 [M+H] ⁺ .

Step D - Synthesis of Intermediate 36d To a solution of intermediate 36c (420 mg, 0.768 mmol) in DCM (1.5 mL) was added aqueous HCl (1.5 mL, 12 N) at 0°C. The reaction mixture was stirred at 25°C for 1.5 hours, and then the solvent was removed with a stream of nitrogen. The resulting residue was purified by reverse phase HPLC (Boston Uni C18 40*150*5um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1). The product fractions were combined and freeze-dried to give intermediate 36d. LC-MS (ESI) m/z: 391.2 [M+H] ⁺ .

Step E - Synthesis of Compound 71 To a solution of intermediate 36d (220 mg, 0.563 mmol) in DMA (4 mL) was added at 0 °C Molecular sieves (100 mg) and intermediate 5 (301 mg, 0.620 mmol). The reaction mixture was stirred at 25 ° C for 12 hours and then filtered. The filtrate was diluted with MeOH (1 mL) and purified by reverse phase HPLC (Boston Uni C1840*150*5um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1) and then freeze-dried to obtain compound 71 as a TFA salt. The TFA salt was further purified by reverse phase HPLC (WelchXtimate C18 150*25mm*5um; conditions: water (0.225% FA)-ACN; start B 0, end B 20; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 2) and then freeze-dried to give compound 71 as formate salt. LC-MS (ESI): m/z 737.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.39-7.31 (m, 2H), 6.88 (d, J=8.6 Hz, 1H), 6.79 (s, 1H), 4.63 (s, 1H), 4.38 (br d, J = 10.6 Hz, 1H), 3.28-3.15 (m, 1H), 2.92-2.70 (m, 2H), 2.15-2.01 (m, 3H), 2.01-1.92 (m, 2H), 1.94-1.66 (m, 3H), 1.65-1.51 (m, 2H), 1.50 (s, 3H), 1.47 (s, 3H), 1.43 (s, 3H), 1.26 (s, 3H).

Example 49: Preparation of Compound 72

(S)-2-((R)-6-(N-((1s,4S)-4-amino-1-methylcyclohexyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Compound 72 was prepared according to the procedures in Step A to Step E of Example 48 starting from Intermediate 35b-2 and Intermediate 6c. Compound 72: LC-MS (ESI): m/z 737.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.44-7.38 (m, 2H), 6.89 (d, J=8.2 Hz, 1H), 6.79 (s, 1H), 4.64 (s, 1H), 4.37 (br d, J = 9.8 Hz, 1H), 3.25-3.10 (m, 1H), 2.90-2.70 (m, 2H), 2.40-2.25 (m, 2H), 2.17-2.02 (m, 1H), 2.01-1.88 (m, 2H), 1.82-1.63 (m, 1H), 1.64-1.47 (m, 4H), 1.50 (s, 3H), 1.43 (s, 3H), 1.39 (s, 3H), 1.26 (s, 3H).

Example 50: Preparation of Intermediates 37d-1 and 37d-2

Step A - Synthesis of Intermediate 37a To a stirred solution of intermediate 28a (5.0 g, 22.00 mmol) in MeOH (100 mL) at 0°C was added p-toluenesulfonic acid monohydrate (0.837 g, 4.40 mmol). The reaction was stirred at 25°C for 2 hours, then diluted with saturated aqueous NaHCO ₃ solution (60 mL) and extracted with EtOAc (40 mL×3). The organic layers were combined, dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 40 g Agela Silica Flash Column, 0-50% EtOAc/petroleum ether gradient elution @ 40 mL/min) to afford intermediate 37a. LC-MS (ESI): m/z 294.4 [M+H] ⁺ .

Step B - Synthesis of Intermediate 37b To a solution of intermediate 37a (1.8 g, 6.94 mmol) in anhydrous THF (30 mL) was added Ph ₃ P (2.185 g, 8.33 mmol) and phthalimide (1.328 g, 9.02 mmol) at 0°C under nitrogen atmosphere. DIAD (1.754 mL, 9.02 mmol) was added to the reaction mixture at 0°C. The reaction was warmed to 25°C and stirred at 25°C for 16 hours and concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (Biotage; 20 g Agela Silica Flash Column, 0-30% EtOAc/petroleum ether gradient elution @ 30 mL/min) to afford intermediate 37b. LC-MS (ESI): m/z 777.4 [2M+H] ⁺ .

Step C-Synthesis of Intermediate 37c A mixture of intermediate 37b (2.0 g, 5.15 mmol) and hydrazine hydrate (1.516 g, 25.7 mmol) in MeCN (20 mL) was stirred at 25 °C under nitrogen atmosphere for 2 hours and then concentrated in vacuo. The resulting residue was diluted with water (25 mL) and extracted with a mixed solvent of 10:1 DCM/MeOH (20 mL×3). The combined organic layer was washed with brine (30 mL), dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo to give intermediate 37c, which was used in the next step without further purification. LC-MS (ESI): m/z 259.3 [M+H] ⁺ .

Step D - Synthesis of Intermediates 37d-1 and 37d-2 To a solution of intermediate 37c (1.3 g, 5.03 mmol) in THF (10 mL) and water (5 mL) was added benzyl chloroformate (1.288 g, 7.55 mmol) and sodium carbonate (1.067 g, 10.06 mmol) dropwise at 0°C. The reaction was stirred at 25°C for 16 hours and then concentrated under reduced pressure. The resulting residue was purified by reverse phase HPLC (column: Boston Uni C1840*150*5um; conditions: water (0.1% TFA)-ACN; start B 45, end B 75; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 2) to give the product as a mixture of stereoisomers. The mixture of stereoisomers (1.0 g, 2.55 mmol) was further separated by SFC (column: DAICEL CHIRALCEL OJ-H 250 mm*30 mm, 5 um; conditions: 0.1% NH ₃ ·H ₂ O-EtOH; start B 25%; flow rate (mL/min) 60; injection 75) to give intermediate 37d-1 (first eluting stereoisomer) and intermediate 37d-2 (second eluting stereoisomer), respectively.

Intermediate 37d-1: ¹ H NMR (CDCl ₃ , 400 MHz) δ: 7.42-7.29 (m, 5H), 5.11 (s, 2H), 4.99 (brs, 1H), 4.50 (br s, 1H), 3.58-3.45 (m, 1H), 3.34 (d, J=5.9 Hz, 2H), 3.16 (s, 3H), 1.95-1.75 (m, 2H), 1.69-1.52 (m, 4H), 1.49-1.33 (m, 2H), 1.44 (s, 9H).

Intermediate 37d-2: ¹ H NMR (CDCl ₃ , 400 MHz) δ: 7.57-7.30 (m, 5H), 5.07 (s, 2H), 4.90 (s, 1H), 4.48 (s, 1H), 3.49-3.32 (m, 1H), 3.20 (d, J=5.2 Hz, 2H), 3.14 (s, 3H), 1.87-1.71 (m, 4H), 1.44 (s, 9H), 1.37-1.15 (m, 4H).

Example 51: Preparation of Compound 73

(S)-2-((R)-6-(N-((1s,4S)-4-(aminomethyl)-4-methoxycyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A-Synthesis of Intermediate 38a A solution of intermediate 37d-2 (450 mg, 1.147 mmol) in HCl/EtOAc (4M, 6 mL) was stirred at 25°C for 0.5 hours. The reaction mixture was then concentrated to give intermediate 38a, which was used in the next step without further purification. LC-MS (ESI): m/z 293.2 [M+H] ⁺ .

Step B - Synthesis of Intermediate 38b To a stirred solution of Intermediate 3c (535 mg, 1.147 mmol) and Intermediate 38a (335 mg, 1.147 mmol) in MeCN (10 mL) at 25°C were added acetic acid (0.197 mL, 3.44 mmol) and potassium acetate (338 mg, 3.44 mmol) in sequence. The reaction was stirred at 80°C for 30 minutes, then diluted with water (30 mL) and extracted with EtOAc (50 mL x 3). The organic layers were combined, dried over _{anhydrous Na2SO4} , filtered and concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 20 g Agela Silica Flash Column, 0-5% DCM/MeOH gradient elution @ 30 mL/min) to afford Intermediate 38b. LC-MS (ESI): m/z 711.4 [M+H] ⁺ .

Step C - Synthesis of Intermediate 38c A solution of intermediate 38b (400 mg, 0.563 mmol) in HBr/AcOH (8 mL, 40%) was stirred at 25°C for 2 hours. The reaction mixture was then filtered and the filtrate was concentrated under reduced pressure. The resulting residue was purified by reverse phase HPLC (column: Boston Uni C18 40*150*5um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1) to give intermediate 38c. LC-MS (ESI): m/z 421.0 [M+H] ⁺ .

Step D-Synthesis of Compound 73 Intermediate 5 (130 mg, 0.357 mmol) was added to a mixture solution of intermediate 38c (150 mg, 0.357 mmol) in DMA (5 mL) at 0°C. The reaction was stirred at 25°C for 16 hours. The reaction solvent was then evaporated with a stream of nitrogen and the resulting residue was purified by reverse phase HPLC (column: Boston Uni C18 40*150*5um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 2) to give a crude product. The crude product was purified by a second reverse phase HPLC (column: Phenomenex Luna C18 75*30mm*3um; condition: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 11; 100% B retention time (min) 2; flow rate (mL/min) 30; injection 9) to give compound 73 as a TFA salt. The TFA salt was converted to a formate salt by reverse phase HPLC (column: WelchXtimate C18 150*25mm* _5um ; condition: water (10mM _NH4HCO3 )-ACN; start B 0, end B18; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 2) to give compound 73 as a formate salt. LC-MS (ESI): m/z 767.4 [M+H] ⁺ . ¹ H NMR (CD ₃ CN+D ₂ O, 400 MHz) δ: 7.42-7.33 (m, 2H), 6.89 (d, J＝8.6 Hz, 1H), 6.78 (s, 1H), 4.61 (s, 1H), 4.38 (br d, J = 10.2 Hz, 1H), 3.62-3.46 (m, 1H), 3.12 (s, 3H), 2.96 (s, 2H), 2.89-2.70 (m, 2H), 2.15-2.00 (m, 1H), 1.92-1.78 (m, 4H), 1.80-1.65 (m, 1H), 1.60-1.47 (m, 2H), 1.52 (s, 3H), 1.43 (s, 3H), 1.40-1.32 (m, 2H), 1.26 (s, 3H).

Example 52: Preparation of Intermediates 39d-1 and 39d-2

Step A - Synthesis of Intermediate 39a To a solution of methyl 3-oxocyclobutane-1-carboxylate (13.48 g, 105 mmol) in THF (300 mL) and acetic acid (6 mL, 105 mmol) was added dibenzylamine (20.76 g, 105 mmol). After stirring at room temperature (22 ° C.) for 10 minutes, sodium cyanoborohydride (19.83 g, 316 mmol) was added in portions over 30 minutes. The reaction mixture was stirred at room temperature (22 ° C.) for 16 hours, and then a stirred saturated aqueous NaHCO ₃ solution (200 mL) was added. After stirring at 22 ° C. for 10 minutes, the resulting mixture was extracted with EtOAc (100 mL×3). The combined organic layers were washed with brine (150 mL×2), dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (Biotage; 80 g Agela Silica Flash Column, 7.5-100% EtOAc/petroleum ether gradient elution @ 45 mL/min) to afford intermediate 39a. TLC: petroleum ether/EtOAc (20:1), _Rf = 0.6 (ninhydrin stain).

Step B - Synthesis of Intermediate 39b To a solution of diisopropylamine (9.58 mL, 67.9 mmol) in THF (50 mL) at -70°C was added n-butyllithium (27.1 mL, 67.9 mmol, 2.5 M in hexane). The reaction was stirred at -70°C for 30 minutes. Then a solution of Intermediate 39a (7.0 g, 22.62 mmol) in THF (25 mL) was added while maintaining the temperature at -70°C. After the reaction mixture was stirred at -70°C for 20 minutes, a solution of iodomethane (8.35 mL, 134 mmol) in THF (25 mL) was added. The reaction was stirred at -70°C for 1 hour and then quenched with saturated aqueous NH ₄ Cl solution (40 mL). The resulting mixture was stirred at 0°C for 15 minutes. It was then extracted with EtOAc (3×40 mL). The combined organic layers were washed with brine (50 mL), dried over anhydrous Na ₂ SO ₄ , filtered and concentrated in vacuo. The resulting residue was purified by flash silica chromatography (Biotage; 40 g Agela Silica Flash Column; 0-9% EtOAc/petroleum ether gradient elution @ 40 mL/min) to afford Intermediate 39b. LC-MS (ESI): m/z 324.6 [M+H] ⁺ .

Step C - Synthesis of intermediate 39c To a solution of intermediate 39b (6.55 g, 20.25 mmol) in MeOH (150 mL) was added a solution of NaOH (2.430 g, 60.8 mmol) in H ₂ O (30 mL). The reaction was stirred at 70° C. for 1.5 hours, and then the solvent was removed in vacuo. The resulting residue was diluted with H ₂ O (10 mL), and then the pH was adjusted to pH 4-5 with aqueous HCl (2 M). The resulting mixture was filtered, and the filter cake was dried to give intermediate 39c. Additional product was obtained by extracting the filtrate with EtOAc (40 mL×4) and concentrating the combined organic layers. LC-MS (ESI): m/z 310.2 [M+H] ⁺ .

Step D - Synthesis of Intermediates 39d-1 and 39d-2 To a solution of intermediate 39c (2000 mg, 4.85 mmol) in toluene (45 mL) was added Molecular sieves (50 mg) and triethylamine (2.70 mL, 19.39 mmol), followed by the slow addition of diphenylphosphino azide (1769 mg, 7.27 mmol) at 0 ° C. The reaction was heated to 45 ° C and stirred at 45 ° C for 2 hours. The temperature was then raised to 85 ° C, and 2-(trimethylsilyl)ethanol (2293 mg, 19.39 mmol) was added. The reaction mixture was stirred at 85 ° C for 16 hours. The reaction mixture was then filtered and the filtrate was concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (Biotage; 40 g Agela Silica Flash Column, EtOAc/petroleum ether 0-8% gradient elution @ 30 mL/min) to obtain the product as a mixture of stereoisomers. LC-MS (ESI): m/z 425.3 [M+H] ⁺ . The mixture of stereoisomers was further purified by SFC (column: Daicel chiralpak IG (250 mm*30 mm, 10 um); condition 0.1% NH ₃ ·H ₂ O EtOH; start B 30%; flow rate (mL/min) 200; injection 120) to give intermediate 39d-1 (first eluting stereoisomer) and intermediate 39d-2 (second eluting stereoisomer).

Intermediate 39d-1: LC-MS (ESI): m/z 425.3 [M+H] ⁺ . ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.32-7.21 (m, 10H), 4.66 (br s, 1H), 4.13 (br t, J=8.4 Hz, 2H), 3.47 (s, 4H), 3.32-3.18 (m, 1H), 2.32-2.18 (m, 2H), 1.97-1.81 (m, 2H), 1.42 (s, 3H), 0.97 (t, J=8.4 Hz, 2H), 0.04 (s, 9H).

Intermediate 39d-2: LC-MS (ESI): m/z 425.3 [M+H] ⁺ . ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.34-7.16 (m, 10H), 4.71 (br s, 1H), 4.10 (t, J=8.4 Hz, 2H), 3.48 (s, 4H), 3.06-2.93 (m, 1H), 2.23-2.01 (m, 4H), 1.37 (s, 3H), 0.96 (t, J=8.4 Hz, 2H), 0.03 (s, 9H).

Example 53: Preparation of Compound 74

(S)-2-((R)-6-(N-((1r,3R)-3-amino-3-methylcyclobutyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 40a To a solution of intermediate 39d-1 (700 mg, 1.648 mmol) in MeOH (20 mL) was added palladium hydroxide (579 mg, 0.824 mmol, 20 wt.%). The mixture was stirred at 20° C. under H ₂ atmosphere (45 psi) for 20 hours. The reaction mixture was then filtered and the filtrate was concentrated in vacuo to afford intermediate 40a, which was used in the next step without further purification. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 4.69 (br s, 1H), 4.12 (t, J=8.0 Hz, 2H), 3.62-3.48 (m, 1H), 2.62-2.39 (m, 2H), 1.75-1.61 (m, 2H), 1.43 (s, 3H), 0.97 (t, J=8.0 Hz, 2H), 0.04 (s, 9H).

Step B - Synthesis of Intermediate 40b To a stirred mixture of intermediate 40a (150 mg, 0.614 mmol) and intermediate 3c (360 mg, 0.606 mmol) in MeCN (6 mL) was added acetic acid (0.141 mL, 2.455 mmol). The reaction was stirred at 80 °C for 20 minutes. The reaction mixture was then concentrated in vacuo to give the crude intermediate 40b, which was used in the next step without further purification. LC-MS (ESI): m/z 663.8 [M+H] ⁺ .

Step C-Synthesis of Intermediate 40c A mixture of intermediate 40b (407 mg, 0.614 mmol) in DCM (2.5 mL) and HCl aqueous solution (2.5 mL, 12 N) was stirred at 20°C for 30 minutes. The reaction solvent was then removed in vacuo and the residue was purified by reverse phase HPLC (Boston Uni C1840*150*5um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 20; injection 1) to give intermediate 40c. LC-MS (ESI): m/z 363[M+H] ⁺ .

Step D-Synthesis of Compound 74 To a solution of intermediate 40c (200 mg, 0.386 mmol) in DMA (2.5 mL) was added intermediate 5 (194 mg, 0.425 mmol). The reaction mixture was stirred at 24 °C for 16 hours. The reaction mixture was then diluted with MeOH (2.0 mL) and purified by reverse phase HPLC (Boston Uni C18 40*150*5um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1) to give compound 74 as a TFA salt. The TFA salt was converted to formate by reverse phase HPLC (Welch Xtimate C18 150*25mm*5um; conditions: water (0.225% FA)-ACN; start B 0, end B1; 8 gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 2) to give compound 74 as formate salt. LC-MS (ESI): m/z 709.0 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.37-7.27 (m, 2H), 6.86 (d, J=8.6 Hz, 1H), 6.79 (s, 1H), 4.61 (s, 1H), 4.39 (br d, J=11.7 Hz, 1H), 4.31-4.19 (m, 1H), 2.94-2.71 (m, 4H), 2.50-2.26 (m, 2H), 2.20-2.05 (m, 1H), 1.82-1.65 (m, 1H), 1.54 (s, 3H), 1.48 (s, 3H), 1.43 (s, 3H), 1.26 (s, 3H).

Example 54: Preparation of Compound 75

(S)-2-((R)-6-(N-((1s,3S)-3-amino-3-methylcyclobutyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Compound 75 was prepared from intermediate 39d-2 according to the procedures in step A to step D of Example 53. Compound 75: LC-MS (ESI): m/z 709.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.42-7.34 (m, 2H), 6.86 (d, J=8.6 Hz, 1H), 6.78 (s, 1H), 4.60 (s, 1H), 4.35 (br d, J = 10.4 Hz, 1H), 4.19-4.06 (m, 1H), 2.86-2.68 (m, 2H), 2.70-2.55 (m, 2H), 2.54-2.44 (m, 2H), 2.16-1.95 (m, 1H), 1.76-1.58 (m, 1H), 1.48 (s, 3H), 1.45 (s, 3H), 1.42 (s, 3H), 1.24 (s, 3H).

Example 55: Preparation of Intermediates 41b-1 and 41b-2

Step A - Synthesis of Intermediates 41a-1 and 41a-2 To a solution of tert-butyl (1R, 5S)-8-amino-3-azabicyclo[3.2.1]octane-3-carboxylate (1.28 g, 5.66 mmol) in DCM (45 mL) was added TEA (1.971 mL, 14.14 mmol) and n-(phenoxycarbonyloxy)succinimide (1.550 g, 6.22 mmol). The reaction was stirred at 25 °C for 16 hours, then diluted with water (50 mL) and extracted with DCM (50 mL x 3). The organic layers were combined, washed with brine (50 mL), dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (ISCO; 12 g Agela Silica Flash Column, 0-30% EtOAc/petroleum ether gradient elution @ 30 mL/min) to give the product as a mixture of stereoisomers. LC-MS (ESI): m/z 383.3 [M+Na] ⁺ . The mixture of stereoisomers was further purified by SFC (column: DAICEL CHIRALCEL OJ-H 250 mm*30 mm, 5 um; condition 0.1% NH ₃ H ₂ O/IPA; start B 15%, end B 15%; flow rate (mL/min) 60; injection 220) to separately obtain intermediate 41a-1 (first eluting stereoisomer; LC-MS (ESI): m/z 383.3 [M+Na] ⁺ ) and intermediate 41a-2 (second eluting stereoisomer; LC-MS (ESI): m/z 383.3 [M+Na] ⁺ ).

Step B - Synthesis of intermediates 41b-1 and 41b-2 A mixture of intermediate 41a-1 (340 mg, 0.943 mmol) and Pd/C (10 wt.%, 200 mg, 0.188 mmol) in MeOH ( ₁₀ mL) was stirred under H2 (15 psi) at 25°C for 2 h. The reaction was then filtered and the filtrate was concentrated in vacuo to afford intermediate 41b-1, which was used in the next step without further purification. ¹ H NMR (400 MHz, CD ₃ OD) δ: 3.89-3.75 (m, 2H), 2.98-2.86 (m, 1H), 2.94 (s, 1H), 2.86-2.76 (m, 1H), 2.01-1.89 (m, 2H), 1.94-1.74 (m, 2H), 1.47-1.43 (br s, 2H) 1.47 (s, 9H).

Intermediate 41b-2 was prepared according to the procedure in Step B of Example 55 from Intermediate 41a-2.

Example 56: Preparation of Compounds 76 and 77

(S)-2-((R)-6-(N-((1R,5S,8s)-3-azabicyclo[3.2.1]octan-8-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1R,5S,8r)-3-azabicyclo[3.2.1]octan-8-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

According to the procedure in step E to step G of Example 34, compounds 76 and 77 were prepared starting from intermediate 41b-1 and intermediate 41b-2, respectively.

Compound 76: LC-MS (ESI): m/z 735.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.39-7.27 (m, 2H), 6.87 (d, J=8.2 Hz, 1H), 6.79 (s, 1H), 4.62 (s, 1H), 4.45-4.38 (m, 1H), 3.89 (s, 1H), 3.24 (s, 4H), 2.89-2.71 (m, 2H), 2.71-2.56 (m, 2H), 2.23-2.01 (m, 3H), 1.84-1.61 (m, 3H), 1.49 (s, 3H), 1.42 (s, 3H), 1.25 (s, 3H).

Compound 77: LC-MS (ESI): m/z 735.6 [M+H] ⁺ . ¹ H NMR (DMSO-d ₆ +D ₂ O, 400 MHz) δ: 7.56-7.46 (m, 2H), 6.93 (d, J=8.6 Hz, 1H), 6.75 (s, 1H), 4.60 (s, 1H), 4.38 (br d, J=11.3 Hz, 1H), 3.76 3.65(m,1H),3.55-3.41(m,1H),3.38-3.23(m,1H),3.01-2.89(m,2H),2.88-2.68(m,2H),2.56-2.48(m,2H),2.01-1.85(m,3H),1.76-1.65(m,2H),1.45(s,3H),1.45-1.35(m,1H),1.39(s,3H),1.24(s,3H).

Example 57: Preparation of Intermediates 42g-1 and 42g-2

Step A - Synthesis of Intermediate 42a To a stirred solution of diisopropylamine (7.94 mL, 56.2 mmol) in THF (65 mL) at -70°C was added n-butyllithium (24.05 mL, 60.1 mmol, 2.5 M in hexanes). The reaction was stirred at -70°C for 30 minutes, then a solution of 3-(dibenzylamino)cyclobutane-1-carboxylic acid methyl ester (6.0 g, 19.39 mmol) in THF (10 mL) was added. The reaction mixture was stirred at -70°C for 30 minutes. (1H-Benzo[d][1,2,3]triazol-1-yl)methanol (8.26 g, 38.8 mmol) was then added portionwise and the reaction was stirred at -70°C for 1 hour. The reaction was then quenched with saturated aqueous NH ₄ Cl solution (20 mL). The resulting mixture was stirred at 0°C for 15 minutes, then extracted with EtOAc (3×20 mL). The combined organic layers were washed with brine (30 mL), dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated in vacuo. The residue was purified by flash silica gel chromatography (Biotage; 80 g Agela Silica Flash Column, petroleum ether/EtOAc=23% gradient elution @ 45 mL/min) to afford Intermediate 42a. LC-MS (ESI): m/z 340.5 [M+H] ⁺ .

Step B-Synthesis of intermediate 42b To a stirred solution of intermediate 42a (5.0 g, 14.73 mmol) and TEA (4.11 mL, 29.5 mmol) in THF (130 mL) was added dropwise a solution of methanesulfonyl chloride (2.109 mL, 27.3 mmol) in THF (5 mL) at 0°C. The reaction mixture was heated to 25°C and stirred at 25°C for 1.5 hours, then cooled to 0°C and quenched by dropwise addition of saturated aqueous _NaHCO3 solution (60 mL). The resulting mixture was extracted with MTBE (60 mL×3). The organic layers were combined, dried over _{anhydrous Na2SO4} , and filtered. The filtrate was concentrated under reduced pressure to give intermediate 42b as a mixture of cis/trans stereoisomers, which was used in the next step without further purification. ¹ H NMR (400 MHz, CDCl ₃ ) δ: =7.34-7.24 (m, 10H), 4.42-4.37 (two s, 2H), 3.76-3.72 (two s, 3H), 3.57-3.45 (two s, 4H), 3.44-3.20 (m, 1H), 3.02-2.99 (two s, 3H), 2.49-2.37 (m, 2H), 2.15-1.94 (m, 2H).

Step C-Synthesis of Intermediate 42c To a solution of intermediate 42b (6.0 g, 12.93 mmol) in DMF (60 mL) stirred at 20°C was added sodium azide (1.360 g, 20.92 mmol) in one portion. The reaction mixture was heated to 70°C and stirred for 16 hours. The reaction mixture was then diluted with water (400 mL) and extracted with EtOAc (150 mL×3). The combined organic layers were washed with brine (100 mL×2), dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo to give intermediate 42c, which was used in the next step without further purification. LC-MS (ESI): m/z 365.2[M+H] ⁺ .

Step D - Synthesis of intermediate 42d To a stirred solution of intermediate 42c (4.7 g, 12.90 mmol) in water (18 mL) and THF (90 mL) was added Ph ₃ P (5.75 g, 21.92 mmol). The reaction was stirred at 25° C. for 16 hours, then most of the solvent was removed under vacuum. The resulting residue was freeze-dried to give intermediate 42d, which was used in the next step without further purification. LC-MS (ESI): m/z 339.1 [M+H] ⁺ .

Step E - Synthesis of Intermediates 42e-1 and 42e-2 To a solution of intermediate 42d (4.36 g, 12.88 mmol) and TEA (2.155 mL, 15.46 mmol) in DCM (75 mL) was added di-tert-butyl dicarbonate (3.09 g, 14.17 mmol). The reaction was stirred at 25 °C for 16 hours. The solvent was then removed under reduced pressure and the resulting residue was purified by flash silica gel chromatography (Biotage; 80 g Agela Silica Flash Column, 6% EtOAc/petroleum ether gradient elution @ 60 mL/min) to give the product as a mixture of stereoisomers. LC-MS (ESI): m/z 439.5 [M+H] ⁺ . The diastereomeric mixture was further purified by SFC (column: DAICEL CHIRALPAKAD 250 mm*50 mm, 10 um; condition: 0.1% NH ₃ H ₂ O EtOH; start B 30%, end B 30%; flow rate (mL/min) 200; injection 120) to give intermediate 42e-1 (first eluting stereoisomer, LC-MS (ESI): m/z 439.3 [M+H] ⁺ ) and intermediate 42e-2 (second eluting stereoisomer, LC-MS (ESI): m/z 439.6 [M+H] ⁺ ).

Step F - Synthesis of Intermediate 42f-1 To a stirred solution of intermediate 42e-1 (650 mg, 1.482 mmol) in THF (14 mL) was slowly added lithium aluminum hydride (170 mg, 4.48 mmol) at 0°C. The reaction was stirred at 25°C for 2.0 hours and then cooled to 0°C, followed by the slow addition of water (0.18 mL), 15% sodium hydroxide solution (0.36 mL) and water (0.540 mL). The resulting mixture was filtered through Celite ^TM , the filtrate was dried over _{anhydrous Na2SO4} , and concentrated in vacuo to afford intermediate 42f-1, which was used in the next step without further purification. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.34-7.28 (m, 8H), 7.28-7.21 (m, 2H), 4.87 (br s, 1H), 3.64-3.54 (m, 1H), 3.47 (s, 4H), 3.45 (br s, 2H), 3.19 (d, J=6.6 Hz, 2H), 3.16-3.02 (m, 1H), 1.99-1.90 (m, 2H), 1.67-1.55 (m, 2H), 1.45 (s, 9H).

Step G - Synthesis of Intermediate 42g-1 To a solution of intermediate 42f-1 (600 mg, 1.461 mmol) and acetic acid (0.251 mL, 4.38 mmol) in MeOH (10 mL) was added Pd/C (10 wt.%, 311 mg, 0.292 mmol). The reaction was stirred at 25 °C under _H2 atmosphere (15 psi) for 16 hours and then filtered. The filtrate was concentrated in vacuo and freeze-dried to afford intermediate 42g-1 which was used without further purification. ¹ H NMR (400 MHz, _CD3OD ) δ: 3.76-3.61 (m, 1H), 3.49 (s, 2H), 3.13 (s, 2H), 2.26-2.17 (m, 2H), 1.96-1.86 (m, 2H), 1.42 (s, 9H).

Intermediate 42g-2 was prepared from intermediate 42e-2 according to the procedures described in Step F and Step G of Example 57. ¹ H NMR (400 MHz, CD ₃ OD) δ: 3.78-3.61 (m, 1H), 3.42 (s, 2H), 3.18 (s, 2H), 2.31-2.19 (m, 2H), 2.03-1.84 (m, 2H), 1.44 (s, 9H).

Example 58: Preparation of Compound 78

(S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)-3-(hydroxymethyl)cyclobutyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of intermediate 43a To a stirred solution of intermediate 42g-1 (180 mg, 0.664 mmol) and intermediate 3c (355 mg, 0.598 mmol) in MeCN (8 mL) at room temperature was added acetic acid (0.152 mL, 2.66 mmol). The reaction was stirred at 80°C for 20 minutes and then concentrated in vacuo. The resulting residue was purified by reverse phase HPLC (Biotage; 20 g Agela, C18, 20-35 μm, 50% MeCN/H ₂ O (0.5% TFA) gradient elution @ 50 mL/min) to afford intermediate 43a. LC-MS (ESI): m/z 649.4 [M+H] ⁺ .

Step B - Synthesis of Intermediate 43b A solution of tert-butyl intermediate 43a (300 mg, 0.462 mmol) in TFA (7 mL) was stirred at 40°C for 1.5 hours. The reaction mixture was then concentrated in vacuo to afford intermediate 43b, which was used in the next step without further purification. LC-MS (ESI): m/z 393.1 [M+H] ⁺ .

Step C - Synthesis of Intermediate 43c A solution of Intermediate 43b (180 mg, 0.459 mmol) and Intermediate 4 (213 mg, 0.459 mmol) in MeOH (10 mL) was stirred at 25° C. for 16 hours. The reaction mixture was then concentrated in vacuo to afford Intermediate 43c, which was used in the next step without further purification. LC-MS (ESI): m/z 839.4 [M+H] ⁺ .

Step D-Synthesis of Compound 78 A 1:1 DCM/TFA (2 mL) solution of intermediate 43c (180 mg, 0.215 mmol) was stirred at 25°C for 50 minutes. The reaction mixture was then concentrated in vacuo and the residue was purified by prep.HPLC (Boston Uni C18, 40*150*5um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10, 100% B retention time (min) 2; flow rate (mL/min) 60; injection 3) to give the product as a TFA salt. The TFA salt was further purified by preparative HPLC (Welch Xtimate C18, 150*25mm*5um; conditions: water (0.225% FA)-ACN; start B 0, end B19; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 2) to give compound 78 as a formate salt. LC-MS (ESI): m/z 739.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.44-7.37 (m, 2H), 6.90 (d, J=8.6 Hz, 1H), 6.78 (s, 1H), 4.60 (s, 1H), 4.38 (br d, J=10.6 Hz, 1H), 4.21-4.12 (m, 1H), 3.67 (s, 2H), 3.10 (s, 2H), 2.89-2.68 (m, 2H), 2.49-2.39 (m, 2H), 2.12-2.01 (m, 3H), 1.85-1.62 (m, 1H), 1.49 (s, 3H), 1.43 (s, 3H), 1.25 (s, 3H).

Example 59: Preparation of Compound 79

(S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)-3-(hydroxymethyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Compound 79 was prepared according to the procedure shown in Step A to Step C of Example 32 starting from the corresponding intermediate 42g-2. LC-MS (ESI): m/z 739.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.46-7.32 (m, 2H), 6.90 (d, J=8.6 Hz, 1H), 6.79 (s, 1H), 4.60 (s, 1H), 4.40 (br d, J=10.6 Hz, 1H), 4.35-4.22 (m, 1H), 3.62 (s, 2H), 3.18 (s, 2H), 2.89-2.68 (m, 2H), 2.47-2.39 (m, 2H), 2.12-2.01 (m, 3H), 1.85-1.62 (m, 1H), 1.51 (s, 3H), 1.43 (s, 3H), 1.25 (s, 3H).

Example 60: Preparation of Compounds 80 and 81

(S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)-3-hydroxycyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)-3-hydroxycyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediates 44a-1 and 44a-2 To a mixture of tert-butyl (3-(amino-methyl)-3-hydroxycyclobutyl)carbamate (3.36 g, 15.54 mmol) and sodium carbonate (4.12 g, 38.8 mmol) in THF (40 mL) and water (20 mL) was added benzyl chloroformate (3.71 g, 21.75 mmol) dropwise. The reaction mixture was stirred at 25° C. for 16 hours, then the solvent was removed under reduced pressure. The resulting residue was purified by flash silica gel chromatography (Biotage; 120 g Agela Silica Flash Column, 8% EtOAc/petroleum ether gradient elution @ 60 mL/min) to give the crude product as a cis/trans mixture. The cis/trans mixture was further purified by SFC (column: DAICEL CHIRALCEL OJ, 250mm*50mm*10um; condition: 0.1% _NH3 · _H2O /EtOH; start B 25%, end B 25%; flow rate (mL/min) 200; injection 120) to give intermediate 44a-1 (latter eluting compound) and intermediate 44a-2 (earlier eluting compound).

Intermediate 44a-1: ¹ H NMR (CD ₃ OD, 400 MHz) δ: 7.48-7.27 (m, 5H), 5.11 (s, 2H), 3.70-3.52 (m, 1H), 3.23 (s, 2H), 2.61-2.40 (m, 2H), 1.90-1.81 (m, 2H), 1.43 (s, 9H).

Intermediate 44a-2: ¹ H NMR (CD ₃ OD, 400 MHz) δ: 7.56-7.27 (m, 5H), 5.08 (s, 2H), 4.28-4.06 (m, 1H) 3.23 (s, 2H), 2.48-2.26 (m, 2H), 2.12-2.04 (m, 2H), 1.40 (s, 9H).

Step B-Synthesis of Intermediate 44b-1 A solution of intermediate 44a-1 (400 mg, 1.142 mmol) in HCl/EtOAc (8 mL, 4 M) was stirred at 25° C. for 0.5 h. The reaction mixture was then concentrated in vacuo to afford intermediate 44b-1, which was used in the next step without further purification. LC-MS (ESI): m/z 251.1 [M+H] ⁺ .

Step C - Synthesis of Intermediate 44c-1 To a stirred solution of Intermediate 3c (380 mg, 0.814 mmol) and Intermediate 44b-1 (285 mg, 0.814 mmol) in MeCN (8 mL) at 25°C were added acetic acid (0.140 mL, 2.443 mmol) and potassium acetate (240 mg, 2.443 mmol) in sequence. The reaction mixture was stirred at 80°C for 30 minutes, then diluted with water (30 mL) and extracted with EtOAc (50 mL x 3). The organic layers were combined, dried over _{anhydrous Na2SO4} , filtered and concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 20 g Agela Silica Flash Column, 5% DCM/MeOH gradient elution @ 30 mL/min) to afford Intermediate 44c-1. LC-MS (ESI): m/z 669.3 [M+H] ⁺ .

Step D - Synthesis of _Intermediate 44d-1 A mixture of intermediate 44c-1 (366 mg, 0.547 mmol) and Pd/C (349 mg, 0.328 mmol, 10 wt.%) in EtOAc (8 mL) was stirred at 25° C. under H 2 (15 psi) for 3 hours. The reaction mixture was then filtered and the filtrate was concentrated to give intermediate 44d-1, which was used in the next step without further purification. LC-MS (ESI): m/z 535.8 [M+H] ⁺ .

Step E - Synthesis of Intermediate 44e-1 A solution of intermediate 44d-1 (250 mg, 0.468 mmol) in TFA (5 mL) was stirred at 40° C. for 1 hour. The reaction mixture was filtered and concentrated to give intermediate 44e-1, which was used in the next step without further purification. LC-MS (ESI): m/z 379.1 [M+H] ⁺ .

Step F - Synthesis of Compounds 80 and 81 To a stirred solution of intermediate 44e-1 (177 mg, 0.468 mmol) in MeOH (5 mL) at 0°C was added intermediate 5 (189 mg, 0.468 mmol). The reaction mixture was stirred at 25°C for 12 hours. The solvent was then removed by purging with a stream of nitrogen and the resulting residue was purified by preparative HPLC (column: Boston Uni C18 40*150*5um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 3) to afford compound 80 as a TFA salt. The TFA salt was further purified by preparative HPLC (column: WelchXtimate C18 150*25mm*5um; conditions: water (0.225% FA)-ACN; start B 0, end B18; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 3) to give compound 80 as a formate salt. LC-MS (ESI): m/z 725.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN): δ: 7.42-7.35 (m, 2H), 6.88 (d, J=8.6 Hz, 1H), 6.79 (s, 1H), 4.61 (s, 1H), 4.38 (br d, J=11.3 Hz, 1H), 3.83-3.73 (m, 1H), 3.07 (s, 2H), 2.84-2.69 (m, 4H), 2.35-2.24 (m, 2H), 2.09-2.01 (m, 1H), 1.84-1.64 (m, 1H), 1.49 (s, 3H), 1.42 (s, 3H), 1.25 (s, 3H).

Compound 81 was prepared from intermediate 44a-2 according to the procedure in step B to step F of Example 60. LC-MS (ESI): m/z 725.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.43-7.35 (m, 2H), 6.88 (d, J=8.6 Hz, 1H), 6.80 (s, 1H), 4.60 (s, 1H), 4.45-4.32 (m, 1H), 4.32-4.26 (m, 1H), 3.08 (s, 2H), 2.92-2.76 (m, 2H), 2.59 (br dd, J=8.0, 13.9 Hz, 2H), 2.35 (br dd, J = 6.7, 14.1 Hz, 2H), 2.09-2.01 (m, 1H), 1.75-1.64 (m, 1H), 1.49 (s, 3H), 1.42 (s, 3H), 1.24 (s, 3H).

Example 61: Preparation of Compounds 82 and 83

(S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)-3-methoxycyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)-3-methoxycyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Compounds 82 and 83 were prepared according to the procedures in Step A to Step F of Example 60 starting from commercially available tert-butyl (3-(aminomethyl)-3-methoxycyclobutyl)carbamate.

Compound 82: LC-MS (ESI): m/z 739.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.46-7.32 (m, 2H), 6.88 (d, J=9.2 Hz, 1H), 6.79 (s, 1H), 4.60 (s, 1H), 4.43-4.29 (m, 1H), 4.25-4.19 (m, 1H), 3.20 (s, 5H), 2.89-2.63 (m, 4H), 2.23 (br dd, J=6.7, 13.4 Hz, 2H), 2.09-2.01 (m, 1H), 1.74-1.61 (m, 1H), 1.48 (s, 3H), 1.42 (s, 3H), 1.24 (s, 3H).

Compound 83: LC-MS (ESI): m/z 739.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.43-7.33 (m, 2H), 6.89 (d, J=8.6 Hz, 1H), 6.79 (s, 1H), 4.61 (s, 1H), 4.45-4.33 (m, 1H), 3.93-3.80 (m, 1H), 3.18 (s, 2H), 3.16 (s, 3H), 2.91-2.72 (m, 2H), 2.60 (br dd, J = 7.6, 13.1 Hz, 2H), 2.48-2.34 (m, 2H), 2.09-2.01 (m, 1H), 1.74-1.58 (m, 1H), 1.49 (s, 3H), 1.42 (s, 3H), 1.25 (s, 3H).

Example 62: Preparation of Intermediates 45b-1 and 45b-2

Step A - Synthesis of Intermediate 45a-1 To a solution of intermediate 39d-1 (900 mg, 2.119 mmol) in MeOH (10 mL) was added palladium hydroxide (744 mg, 1.060 mmol, 20 wt.%). The reaction was stirred at 20 °C under _H2 atmosphere (45 psi) for 20 hours. The reaction mixture was then filtered and the filtrate was concentrated in vacuo. The resulting residue was dissolved in 2:1 THF/water (10 mL), _Na2CO3 ( _0.650 g, 6.14 mmol) was added, followed by Cbz-Cl (0.6 mL, 4.20 mmol). The reaction was stirred at room temperature of 16-22 °C for 16 hours, then diluted with water (20 mL), extracted with EtOAc (10 mL x 3), washed with brine, dried over _{anhydrous Na2SO4} , and filtered. The filtrate was concentrated and the resulting residue was purified by silica gel chromatography (Biotage; 4 g Agela Silica Flash Column, 50% EtOAc/petroleum ether gradient elution @ 40 mL/min) to afford crude intermediate 45a-1. LC-MS (ESI): m/z 757.6 [2M+H] ⁺ .

Step B - Synthesis of Intermediates 45b-1 and 45b-2 A solution of intermediate 45a-1 (0.5 g, 1.321 mmol) in 5:1 TFA/DCM (3 mL) was stirred at 25° C. for 0.5 h. The reaction solvent was then removed with a stream of nitrogen to afford intermediate 45b-1, which was used in the next step without further purification. LC-MS (ESI): m/z 757.6 [2M+H] ⁺ .

Intermediate 45b-2 was prepared from Intermediate 39d-2 according to the procedure used in Example 62. LC-MS (ESI): m/z 235.1 [M+H] ⁺ .

Example 63: Preparation of Compounds 84 and 85

(S)-2-((R)-6-(N-((1r,3R)-3-amino-1-methylcyclobutyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1s,3S)-3-amino-1-methylcyclobutyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

According to the procedures in step A to step E of Example 48, compounds 84 and 85 were prepared starting from the corresponding intermediate 45b-1 and intermediate 45b-2.

Compound 84: LC-MS (ESI): m/z 709.5 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O) δ: 7.47-7.33 (m, 2H), 6.95-6.86 (m, 2H), 4.66 (s, 1H), 4.46 (br d, J=9.4 Hz, 1H), 4.01-3.91 (m, 1H), 3.01-2.88 (m, 2H), 2.88-2.72 (m, 2H), 2.41 (br t, J=11.2 Hz, 2H), 2.16-2.04 (m, 1H), 1.89-1.75 (m, 1H), 1.56 (s, 3H), 1.55 (s, 3H), 1.44 (s, 3H), 1.23 (s, 3H).

Compound 85: LC-MS (ESI): m/z 709.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.43-7.35 (m, 2H), 6.88 (d, J=8.6 Hz, 1H), 6.79 (s, 1H), 4.59 (s, 1H), 4.38 (br d, J=11.0 Hz, 1H), 3.82-3.68 (m, 1H), 2.88-2.67 (m, 4H), 2.57-2.47 (m, 2H), 2.12-2.01 (m, 1H), 1.77-1.61 (m, 1H), 1.49 (s, 6H), 1.42 (s, 3H), 1.25 (s, 3H).

Example 64: Preparation of Intermediates 46c-1 and 46c-2

Step A - Synthesis of Intermediate 46a To a stirred solution of methyl 2-(1-amino-3-((tert-butoxycarbonyl)amino)cyclobutyl)acetate (1.2 g, 4.65 mmol) in THF (30 mL) at 0°C was added _LiAlH4 (0.4 g, 10.54 mmol). The reaction was stirred at 0°C for 1.5 hours, followed by the addition of water (0.4 mL), 10% NaOH (0.8 mL) and water (1.2 mL). The resulting mixture was filtered and the filter cake was rinsed with 10:1 DCM/MeOH. The combined filtrates were concentrated in vacuo to afford Intermediate 46a, which was used in the next step without further purification. ¹ H NMR (400 MHz, CD ₃ OD) δ: 3.76-3.65 (m, 3H), 2.52-2.40 (m, 1H), 2.28-2.14 (m, 1H), 2.01-1.93 (m, 1H), 1.84-1.71 (m, 3H), 1.42 (s, 9H).

Step B - Synthesis of Intermediates 46b-1 and 46b-2 To a solution of intermediate 46a (1.0 g, 4.34 mmol) in MeCN (40 mL) stirred at 0°C was added 1H-imidazole (0.887 g, 13.03 mmol) followed by tert-butyl (3-amino-3-(2-hydroxyethyl)cyclobutyl)carbamate (1 g, 4.34 mmol). The reaction mixture was stirred at 25°C for 16 hours and then the solvent was removed under vacuum. The resulting residue was purified by silica gel chromatography (Biotage; 25 g Agela Silica Flash Column; 100% EtOAc gradient elution; @ 40 mL/min) to afford the d product as a cis/trans mixture. LC-MS (ESI): m/z 469.1 [M+H] ⁺ . The cis/trans mixture was separated by SFC (Phenomenex-Cellulose-2 (250 mm*50 mm, 10 um); conditions: 0.1% NH ₃ ·H ₂ O/EtOH; start B 25%, end B 25%; flow rate (mL/min) 200; injection 120) to give intermediate 46b-1 (first eluting isomer) and intermediate 46b-2 (second eluting isomer).

Intermediate 46b-1: ¹ H NMR (400 MHz, CD ₃ OD) δ: 7.75-7.65 (m, 4H), 7.49-7.35 (m, 6H), 3.85 (br. t, J=6.2 Hz, 2H), 3.74-3.60 (m, 1H), 2.49-2.37 (m, 2H), 1.89-1.74 (m, 4H), 1.43 (s, 9H), 1.04 (s, 9H).

Intermediate 46b-2: ¹ H NMR (400 MHz, CD ₃ OD) δ: 7.74-7.61 (m, 4H), 7.51-7.34 (m, 6H), 4.26-4.09 (m, 1H), 3.82 (t, J=7.60 Hz, 2H), 2.30-2.19 (m, 2H), 2.05-1.92 (m, 2H), 1.84 (t, J=7.60 Hz, 2H), 1.42 (s, 9H), 1.04 (s, 9H).

Step C - Synthesis of Intermediates 46c-1 and 46c-2 A solution of intermediate 46b-1 (450 mg, 0.960 mmol) in a 5:1 DCM:TFA (8 mL) mixed solvent was stirred at 0°C for 30 minutes. TFA (1 mL) was then added and the reaction was stirred for another 0.5 hours at 0°C. The reaction mixture was dried with a stream of nitrogen to give intermediate 46c-1, which was used in the next step without further purification. LC-MS (ESI): m/z 369.1 [M+H] ⁺ .

Intermediate 46c-2 was prepared from Intermediate 46b-2 according to the procedure in Step C of Example 64. LC-MS (ESI): m/z 369.1 [M+H] ⁺ .

Example 65: Preparation of Compounds 86 and 87

(S)-2-((R)-6-(N-((1s,3S)-3-amino-3-(2-hydroxyethyl)cyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1r,3R)-3-amino-3-(2-hydroxyethyl)cyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 47a To a solution of intermediate 46c-1 (354 mg, 0.960 mmol) in MeCN (5 ml) was added potassium acetate (200 mg, 2.038 mmol). After stirring at 25 °C for 5 minutes, acetic acid (206 mg, 3.43 mmol) was added and the reaction was stirred at 25 °C for 5 minutes followed by the addition of intermediate 3c (400 mg, 0.857 mmol). The reaction was stirred at 80 °C for 1.5 hours. The solvent was then removed under vacuum to give intermediate 47a which was used in the next step without further purification. LC-MS (ESI): m/z 787.1 [M+H] ⁺ .

Step B - Synthesis of Intermediate 47b To a stirred solution of intermediate 47a (650 mg, 0.826 mmol) in THF (10 mL) at 0°C was added TBAF (2 mL, 2.000 mmol, 1 N THF solution). The reaction was stirred at 0°C for 0.5 h. The reaction solvent was then removed under vacuum while keeping the bath temperature below 30°C to afford intermediate 47b which was used in the next reaction without further purification. LC-MS (ESI): m/z 549.1 [M+H] ⁺ .

Step C - Synthesis of Intermediate 47c A solution of intermediate 47b (400 mg, 0.729 mmol) in TFA (5 mL) was stirred at 50°C for 0.5 h. The reaction solution was then dried with a stream of nitrogen and the resulting residue was purified by reverse phase HPLC (column: Boston Uni C1840*150*5um; conditions: water (0.1% TFA)-ACN; start B1, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1) to give intermediate 47c. LC-MS (ESI): m/z 393.1 [M+H] ⁺ .

Step D - Synthesis of Compound 86 A solution of intermediate 47c (100 mg, 0.255 mmol) and intermediate 5 (93 mg, 0.255 mmol) in DMA (2 ml) was stirred at 30°C for 16 hours. The reaction mixture was then purified by reverse phase HPLC (column: Boston UniC18 40*150*5um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1) to give compound 86 as a TFA salt. The TFA salt was further purified by reverse phase HPLC (column: Welch Xtimate C18 150*25mm*5um; conditions: water (0.225% FA)-ACN; start B 0, end B18; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 2) to give compound 86 as a formate salt. LC-MS (ESI): m/z 739.3 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ +D ₂ O) δ: 7.48-7.31 (m, 2H), 6.85 (d, J=8.6 Hz, 1H), 6.74 (s, 1H), 4.56 (s, 1H), 4.35 (br d, J=12.1 Hz, 1H), 4.10-3.95 (m, 1H), 3.64 (br t, J=5.7 Hz, 2H), 2.78-2.63 (m, 4H), 2.47-2.31 (m, 2H), 2.02-1.92 (m, 1H), 1.88 (br t, J = 5.7 Hz, 2H), 1.54-1.40 (m, 1H), 1.42 (s, 3H), 1.36 (s, 3H), 1.21 (s, 3H).

Compound 87 was prepared from intermediate 46c-2 according to the procedures in step A to step D of Example 66. LC-MS (ESI): m/z 739.2 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ +D ₂ O) δ: 7.41-7.25 (m, 2H), 6.86 (d, J=8.6 Hz, 1H), 6.73 (s, 1H), 4.54 (s, 1H), 4.35 (br d, J = 12.1 Hz, 1H), 4.31-4.16 (m, 1H), 3.59 (t, J = 6.0 Hz, 2H), 2.86-2.64 (m, 4H), 2.45-2.30 (m, 2H), 2.16-2.03 (m, 1H), 1.89 (t, J = 6.0 Hz, 2H), 1.66-1.51 (m, 1H), 1.49 (s, 3H), 1.36 (s, 3H), 1.21 (s, 3H).

Example 66: Preparation of Compounds 88 and 89

(S)-2-((R)-6-(N-((1r,3R)-3-amino-3-(hydroxymethyl)cyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1s,3S)-3-amino-3-(hydroxymethyl)cyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediates 48a-1 and 48a-2 To a stirred solution of intermediate 42a (1.62 g, 4.77 mmol) and 1H-imidazole (0.877 g, 12.89 mmol) in DCM (45 mL) at 0°C was added a solution of TBSCl (1.439 g, 9.55 mmol) in DCM (3 mL). The reaction was stirred at 28°C for 48 hours. The reaction mixture was then diluted with DCM (100 mL), washed with brine (50 mL), dried over _{anhydrous Na2SO4} , and filtered. The filtrate was concentrated under reduced pressure and the resulting residue was purified by flash silica gel chromatography (ISCO; 24 g Agela Silica Flash Column, 0-5% EtOAc/petroleum ether gradient elution @ 40 mL/min) to afford intermediate 48a-1 and intermediate 48a-2, respectively.

Intermediate 48a-1: ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.34-7.28 (m, 8H), 7.26-7.19 (m, 2H), 3.69 (s, 3H), 3.68 (s, 2H), 3.48 (s, 4H), 3.27-3.19 (m, 1H), 2.36-2.27 (dm, 2H), 2.11-1.96 (m, 2H), 0.91 (s, 9H), 0.03 (s, 6H).

Intermediate 48a-2: ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.33-7.28 (m, 8H), 7.26-7.21 (m, 2H), 3.76 (s, 2H), 3.69 (s, 3H), 3.50 (s, 4H), 3.24-3.11 (m, 1H), 2.38-2.24 (m, 2H), 2.17-2.09 (m, 2H), 0.86 (s, 9H), 0.03 (s, 6H).

Step B-Synthesis of Intermediate 48b-1 To a solution of intermediate 48a-1 (939 mg, 2.070 mmol) in MeOH (14.1 mL) and water (4.7 mL) was added NaOH (497 mg, 12.42 mmol) in one portion. The reaction was stirred at 28 °C for 16 hours and then concentrated under reduced pressure to remove most of the MeOH. The resulting residue was diluted with water (30 mL) and extracted with 2-isopropoxypropane (15 mL×4). The organic layers were combined, dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated under reduced pressure to give intermediate 48b-1, which was used in the next step without further purification. LC-MS (ESI): m/z 440.2 [M+H] ⁺ .

Step C - Synthesis of Intermediate 48c-1 _To a solution of intermediate 48b-1 (650 mg, 1.478 mmol) and TEA (0.309 mL, 2.218 mmol) in toluene (6.5 mL) and THF (6.5 mL) was added DPPA (488 mg, 1.774 mmol) at 28 °C under N2 atmosphere. The reaction was stirred at 65 °C for 2 h, and then 2-(trimethylsilyl)ethanol (1748 mg, 14.78 mmol) was added at the same temperature. The reaction mixture was stirred at 90 °C for another 60 h, and then diluted with saturated aqueous _NaHCO3 solution (35 mL) and extracted with EtOAc (15 mL×3). The organic layers were combined, washed with brine, dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 12 g Agela Silica Flash Column, 0-3% EtOAc/petroleum ether gradient elution @ 30 mL/min) to afford Intermediate 48c-1. LC-MS (ESI): m/z 555.3 [M+H] ⁺ .

Step D - Synthesis of Intermediate 48d-1 A mixture of intermediate 48c-1 (400 mg, 0.721 mmol), AcOH (0.165 mL, 2.88 mmol) and Pd/C (120 mg, 1.128 mmol, 10 wt.%) in MeOH (10 mL) was stirred for 12 h at 28° C. under a hydrogen atmosphere (15 psi). The reaction mixture was then filtered and the filtrate was concentrated in vacuo to afford intermediate 48d-1, which was used in the next step without further purification.

Step E-Synthesis of Intermediate 48e-1 To a stirred solution of intermediate 3c (335 mg, 0.718 mmol) and intermediate 48d-1 (269 mg, 0.718 mmol) in MeOH (6 mL) at 28 °C, acetic acid (0.164 mL, 2.87 mmol) and potassium acetate (211 mg, 2.154 mmol) were added sequentially. The reaction was stirred at 85 °C for 40 minutes, then diluted with water (20 mL) and extracted with EtOAc (15 mL×3). The organic layers were combined, washed with brine, dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo to give intermediate 48e-1, which was used in the next step without further purification. LC-MS (ESI): m/z 793.4 [M+H] ⁺ .

Step F-Synthesis of Intermediate 48f-1 To a stirred solution of intermediate 48e-1 (569 mg, 0.717 mmol) in THF (7 mL) at 28°C was added TBAF (1.793 mL, 1.793 mmol) dropwise. The reaction was stirred at 28°C for 12 hours, then diluted with water (20 mL) and extracted with EtOAc (15 mL x 3). The organic layers were combined, washed with brine, dried over _{anhydrous Na2SO4} , and filtered. The filtrate was concentrated under reduced pressure and the resulting residue was purified by reverse phase HPLC (Biotage; 20 g Agela, C18, 20-35 μm column, 50% MeCN/ _H2O (0.5% TFA) gradient elution @ 50 mL/min) to afford intermediate 48f-1. LC-MS (ESI): m/z 679.3 [M+H] ⁺ .

Step G-Synthesis of Intermediate 48g-1 A solution of intermediate 48f-1 (220 mg, 0.324 mmol) in TFA (2.2 mL, 28.6 mmol) was stirred at 40°C for 70 minutes. The reaction solution was then concentrated under reduced pressure to give intermediate 48g-1, which was used in the next step without further purification. LC-MS (ESI): m/z 379.1 [M+H] ⁺ .

Step H-Synthesis of Compound 88 To intermediate 48g-1 (123 mg, 0.325 mmol) and To a solution of a mixture of 100% 1H-12O molecular sieves (120 mg) in MeOH (4 mL) was added intermediate 5 (118 mg, 0.325 mmol). The reaction was stirred at 28°C for 12 hours, then filtered and the filtrate was concentrated under reduced pressure. The residue was purified by reverse phase HPLC (Boston Uni C18 40*150*5um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 2) and then freeze-dried to give compound 88 as a TFA salt. The TFA salt was further purified by reverse phase HPLC (Welch Xtimate C18 150*25mm*5um; conditions: water (0.225% FA)-ACN; start B 0, end B17; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 3) and then freeze-dried to give compound 88 as a formate salt. LC-MS (ESI): m/z 725.5 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.43-7.33 (m, 2H), 6.88 (d, J=8.2 Hz, 1H), 6.81 (s, 1H), 4.61 (s, 1H), .49-4.26–4 (m, 2H), 3.69 (s, 2H), 2.87-2.69 (m, 4H), 2.51-2.40 (m, 2H), .14-2.022 (m, 1H), 1.79-1.66 (m, 1H), 1.50 (s, 3H), 1.42 (s, 3H), 1.23 (s, 3H).

According to the procedures in Example 66, step B to step H, compound 89 was prepared from intermediate 48a-2. LC-MS (ESI): m/z 725.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.43-7.33 (m, 2H), 6.85 (d, J=8.6 Hz, 1H), 6.82 (s, 1H), 4.61 (s, 1H), 4.35 (br d, J=9.0 Hz, 1H), 4.16-4.02 (m, 1H), 3.70 (s, 2H), 2.84-2.67 (m, 4H), 2.55-2.41 (m, 2H), 2.12-2.01 (m, 1H), 1.77-1.63 (m, 1H), 1.48 (s, 3H), 1.41 (s, 3H), 1.23 (s, 3H).

Example 67: Preparation of Intermediates 49a-1 and 49a-2

Step A - Synthesis of Intermediate 49a-1 and Intermediate 49a-2 To a stirred solution of intermediate 48c-1 (700 mg, 1.261 mmol) in DMF (9.5 mL) was added NaH (111 mg, 2.78 mmol, 60 wt.% in mineral oil) at 0°C. The mixture was stirred at 0°C for 20 min under _N2 . A solution of iodomethane (269 mg, 1.892 mmol) in DMF (1.0 mL) was then added dropwise. The reaction mixture was stirred at 0°C for 15 min and then at 28°C for 2 h. The reaction was quenched with saturated _NH4Cl aqueous solution (50 mL) at 0°C and extracted with EtOAc (15 mL x 3). The organic layers were combined, washed with brine (10 mL), dried over _{anhydrous Na2SO4} and filtered. The filtrate was concentrated under reduced pressure and the residue was purified by flash silica gel chromatography (ISCO; 12 g Agela Silica Flash Column, 0-5% EtOAc/petroleum ether gradient elution @ 30 mL/min) to afford Intermediate 49a-1. LC-MS (ESI): m/z 569.3 [M+H] ⁺ .

Intermediate 49a-2 was prepared from Intermediate 48c-2 according to the procedure of Step A of Example 67. LC-MS (ESI): m/z 569.3 [M+H] ⁺ .

Example 68: Preparation of Compounds 90 and 91

(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1r,3R)-3-(hydroxymethyl)-3-(methylamino)cyclobutyl)amidino)chroman-2-yl)propanoic acid and (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1s,3S)-3-(hydroxymethyl)-3-(methylamino)cyclobutyl)amidino)chroman-2-yl)propanoic acid

According to the procedures in Step E to Step H of Example 66, Compounds 90 and 91 were prepared from the corresponding Intermediate 49a-1 and Intermediate 49a-2.

Compound 90: LC-MS (ESI): m/z 739.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.41-7.32 (m, 2H), 6.87 (d, J=8.6 Hz, 1H), 6.81 (s, 1H), 4.61 (s, 1H), 4.39 (br d, J = 11.3 Hz, 1H), 4.34-4.23 (m, 1H), 3.77 (s, 2H), 2.90-2.74 (m, 4H), 2.58 (s, 3H), 2.49-2.35 (m, 2H), 2.12-2.01 (m, 1H), 1.78-1.62 (m, 1H), 1.49 (s, 3H), 1.42 (s, 3H), 1.23 (s, 3H).

Compound 91: LC-MS (ESI): m/z 739.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.44-7.33 (m, 2H), 6.88-6.76 (m, 2H), 4.60 (s, 1H), 4.35 (br d, J＝9.4 Hz, 1H), 4.15-4.04 (m, 1H), 3.77 (s, 2H), 2.84-2.65 (m, 4H), 2.55 (s, 3H), 2.52-2.39 (m, 2H), 2.12-2.01 (m, 1H), 1.77-1.62 (m, 1H), 1.48 (s, 3H), 1.41 (s, 3H), 1.22 (s, 3H).

Example 69: Preparation of Intermediates 50d-1 and 50d-2

Step A - Synthesis of Intermediate 50a To a solution of 3-(dibenzylamino)-cyclobutane-1-carboxylic acid methyl ester (7.4 g, 23.92 mmol) in H ₂ O (21 mL) and CH ₃ OH (63 mL) at room temperature was added sodium hydroxide (2.87 g, 71.7 mmol). The reaction was stirred at room temperature for 16 hours and then concentrated in vacuo. To the resulting residue was slowly added aqueous HCl (1 M) to adjust the pH to pH 4. The resulting mixture was extracted with 1:10 IPA/DCM (4×220 mL). The combined organic layers were concentrated in vacuo to afford Intermediate 50a, which was used in the next step without further purification. LC-MS (ESI): m/z 295.9 [M+H] ⁺ .

Step B-Synthesis of intermediate 50b To a solution of intermediate 50a (5.8 g, 19.64 mmol) in THF (120 mL) stirred at -65 ° C was added lithium diisopropylamide (34.4 mL, 68.7 mmol, 2M THF / heptane solution). The reaction was stirred at -65 ° C for 50 minutes, and then 1-iodo-2-methoxyethane (5.48 g, 29.5 mmol) was added. The reaction was stirred at 0 ° C for 5 minutes. Then reacted at 25 ° C for 1 hour. The reaction mixture was then diluted with water (50 mL) and the pH was adjusted to pH 3-4 by adding HCl aqueous solution (1 M). The resulting mixture was extracted with 1:10 isopropanol/dichloromethane (200 mL×4) and the combined organic layers were concentrated in vacuo. The product was purified by flash silica gel chromatography ( 40g The resulting residue was purified by silica flash column, 0-40% ethyl acetate/petroleum ether gradient elution @ 60 mL/min) to afford intermediate 50b. LC-MS (ESI): m/z 354.1 [M+H] ⁺ .

Step C-Synthesis of Intermediates 50c-1 and 50c-2 At 25°C, TEA (1.183 mL, 8.49 mmol) and diphenylphosphoryl azide (1.869 g, 6.79 mmol) were added to a stirred solution of THF (20 mL) and toluene (20 mL) of intermediate 50b (2.0 g, 5.66 mmol). The resulting mixture was stirred at 65°C and _N2 atmosphere for 2 hours, and then 2-(trimethylsilyl)ethanol (6.69 g, 56.6 mmol) was added. The reaction was stirred at 90°C for 12 hours, then quenched with water (15 mL) and extracted with EtOAc (100 mL xr3). The combined organic layers were concentrated under reduced pressure and the residue was purified by flash silica chromatography (ISCO; 25 g SepaFlash silica flash column, 0-20% ethyl acetate/petroleum ether gradient (40 mL/min) to give the desired cis- and trans-stereoisomer mixture. LC-MS (ESI): m/z 469.1 [M+H] ⁺ . The cis/trans mixture was further separated by SFC (column: DAICELCHIRALCEL OD (250 mm×50 mm, 10 um); conditions: 0.1% NH ₃ ·H ₂ O-IPA; start B 20%, end B 20%; flow rate (mL/min) 180; injection 180) to give intermediate 50c-1 and intermediate 50c-2, respectively.

Intermediate 50c-1: LC-MS (ESI): m/z 469.2 [M+H] ⁺ . ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.32-7.19 (m, 10H), 5.01 (br s, 1H), 4.11 (br t, J=8.4 Hz, 2H), 3.46 (s, 4H), 3.39 (t, J=6.1 Hz, 2H), 3.33-3.26 (m, 1H), 3.27 (s, 3H), 2.43-2.31 (m, 2H), 2.04 (br t, J=5.9 Hz, 2H), 1.98-1.90 (m, 2H), 0.98-0.94 (m, 2H), 0.06 (s, 9H).

Intermediate 50c-2: LC-MS (ESI): m/z 469.0 [M+H] ⁺ . ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.34-7.17 (m, 10H), 4.23-4.00 (m, 2H), 3.51 (s, 4H), 3.43 (t, J=6.1 Hz, 2H), 3.29 (s, 3H), 3.04-2.90 (m, 1H), 2.49-2.26 (m, 2H), 2.26-2.14 (m, 2H), 1.94 (t, J=6.1 Hz, 2H), 1.01-0.90 (m, 2H), 0.00 (s, 9H).

Step D - Synthesis of Intermediates 50d-1 and 50d-2 To a solution of intermediate 50c-1 (700 mg, 1.493 mmol) in MeOH (20 mL) was added Pd/C (12 mg, 0.011 mmol, 10 wt.%) and acetic acid (0.342 mL, 5.97 mmol). The reaction was stirred at 25 °C and H ₂ (15 psi) for 3 hours. The reaction mixture was then filtered and the filtrate was concentrated in vacuo to afford intermediate 50d-1, which was used in the next step without further purification. LC-MS (ESI): m/z 289.0 [M+H] ⁺ .

Intermediate 50d-2 was prepared from intermediate 50c-2 according to the procedure in step D of Example 69. LC-MS (ESI): m/z 289.0 [M+H] ⁺ .

Example 70: Preparation of Compounds 92 and 93

(S)-2-((R)-6-(N-((1r,3R)-3-amino-3-(2-methoxyethyl)cyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1s,3S)-3-amino-3-(2-methoxyethyl)cyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

According to step E, step G and step H of Example 66, compounds 92 and 93 were prepared from the corresponding intermediate 50d-1 and intermediate 50d-2.

Compound 92: LC-MS (ESI): m/z 753.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.37-7.29 (m, 2H), 6.86 (d, J=8.6 Hz, 1H), 6.79 (s, 1H), 4.61 (s, 1H), 4.39 (br d, J=8.4 Hz, 1H), 4.35-4.27 (m, 1H), 3.54 (t, J=5.5 Hz, 2H), 3.25 (s, 3H), 2.87-2.73 (m, 4H), 2.55-2.41 (m, 2H), 2.17-2.08 (m, 1H), 2.03 (br t, J = 5.5 Hz, 2H), 1.79-1.67 (m, 1H), 1.53 (s, 3H), 1.43 (s, 3H), 1.25 (s, 3H).

Compound 93: LC-MS (ESI): m/z 753.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.46-7.35 (m, 2H), 6.87 (br d, J=8.6 Hz, 1H), 6.78 (s, 1H), 4.61 (s, 1H), 4.34 (br d, J = 11.0 Hz, 1H), 4.12-3.99 (m, 1H), 3.59 (t, J = 5.5 Hz, 2H), 3.27 (s, 3H), 2.85-2.66 (m, 4H), 2.60-2.40 (m, 2H), 2.12-2.02 (m, 1H), 2.01 (t, J = 5.5 Hz, 2H), 1.75-1.57 (m, 1H), 1.48 (s, 3H), 1.43 (s, 3H), 1.25 (s, 3H).

Example 71: Preparation of Compounds 94 and 95 (S)-2-((R)-6-(N-((1S,3R)-3-amino-3-((S)-2,3-dihydroxypropyl)cyclobutyl)-carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene) ((((S)-2-((R)-6-(N-((1R,3R)-3-amino-3-((R)-2,3-dihydroxypropyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid*

Step A - Synthesis of Intermediates 51a-1 and 51a-2 To a stirred solution of methyl 3-(dibenzylamino)cyclobutane-1-carboxylate (10 g, 32.3 mmol) in THF was added a solution of LiHMDS in THF (1 M, 97 mL, 97 mmol) at -70°C (160 mL). The reaction mixture was stirred at -70°C for 15 minutes, then allyl bromide (7.82 g, 64.6 mmol) was added. The reaction mixture was stirred at -70°C for 1.5 hours, then quenched with saturated aqueous NH ₄ Cl solution (200 mL) at 0°C and stirred for 10 minutes. The reaction mixture was then extracted with EtOAc (3×100 mL), and the combined organics were washed with brine (200 mL), dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated under reduced pressure and the residue was purified by flash silica gel chromatography (Biotage; 120 g Agela Silica Flash Column, 3% EtOAc/petroleum ether gradient elution @ 60 mL/min) to obtain the product as a mixture of stereoisomers. The mixture of stereoisomers was separated by SFC (column: DAICEL CHIRALPAK AD (250 mm×50 mm, 10 um); conditions: 0.1% NH ₃ ·H ₂ OIPA, start B 10%, end B 10%; flow rate (mL/min) 220; injection 120) to obtain intermediate 51a-1 (first eluting isomer) and intermediate 51a-2 (second eluting isomer), respectively.

Intermediate 51a-1: LC-MS (ESI): m/z 350.5 [M+H] ⁺ . ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.34-7.28 (m, 8H), 7.26-7.20 (m, 2H), 5.74-5.57 (m, 1H), 5.08-4.97 (m, 2H), 3.69 (s, 3H), 3.47 (s, 4H), 3.26-3.14 (m, 1H), 2.52-2.43 (m, 4H), 1.92-1.82 (m, 2H).

Intermediate 51a-2: LC-MS (ESI): m/z 350.6 [M+H] ⁺ . ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.32-7.28 (m, 8H), 7.27-7.21 (m, 2H), 5.76-5.63 (m, 1H), 5.12-4.99 (m, 2H), 3.68 (s, 3H), 3.49 (s, 4H), 3.24-3.11 (m, 1H), 2.46 (d, J=6.8 Hz, 2H), 2.37-2.28 (m, 2H), 2.13-2.01 (m, 2H).

Step B - Synthesis of Intermediate 51b-1 To a solution of intermediate 51a-1 (3.6 g, 10.30 mmol) in MeOH (65 mL) and H ₂ O (16 mL) was added sodium hydroxide (1.21 g, 30.3 mmol). The reaction was stirred at 75 °C for 5 hours and then concentrated in vacuo. The resulting residue was diluted with H ₂ O (25 mL) and the pH was adjusted to pH 5-6 with aqueous HCl (2 M, 8 mL). The resulting mixture was extracted with EtOAc (30 mL×3). The combined organic layers were dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo to afford intermediate 51b-1. ¹ H NMR (400 MHz, CD ₃ OD) δ: 7.62-7.40 (m, 10H), 5.71-5.56 (m, 1H), 5.10-5.01 (m, 2H), 4.27 (s, 4H), 4.07-3.94 (m, 1H), 2.57-2.50 (m, 2H), 2.47 (d, J=7.1 Hz, 2H), 2.26-2.18 (m, 2H).

Step C - Synthesis of Intermediate 51c-1 To a stirred solution of intermediate 51b-1 (3.96 g, 11.81 mmol) in toluene (40 mL) and THF (40 mL) was added TEA (4.94 mL, 35.4 mmol) and diphenylphosphoryl azide (3.31 mL, 15.35 mmol) at 0°C. The reaction mixture was slowly warmed to 22°C over 1 hour and then stirred at 50°C for 3.5 hours. The solvent was then removed under reduced pressure, with the bath temperature maintained at 22°C. The resulting residue was washed with water (30 mL). The organic layer was separated, cooled to 0°C, and then potassium hydroxide aqueous solution (50% w/v, 25 mL, 11.81 mmol) and tetrabutylammonium iodide (220 mg, 0.596 mmol) were added. The reaction mixture was stirred at 22°C for 1.5 hours, then cooled to 0°C and acidified to pH 2 with HCl aqueous solution (20 mL, 4 M). The resulting aqueous mixture was washed with EtOAc (30 mL), then basified with aqueous KOH (15 mL, 50 wt.%), and extracted with EtOAc (25 mL×3). The combined organic layers were dried over anhydrous Na ₂ SO ₄ , and the solvent was evaporated under reduced pressure to give Intermediate 51c-1, which was used in the next step without further purification. LC-MS (ESI): m/z 307.2 [M+H] ⁺ .

Step D-Synthesis of Intermediate 51d-1 To a solution of intermediate 51c-1 (900 mg, 2.94 mmol) and TEA (0.819 mL, 5.87 mmol) in DCM (22 mL) stirred at 0°C was added 2,2,2-trifluoroacetic anhydride (925 mg, 4.41 mmol). The reaction was stirred at 24°C for 3 hours, then diluted with water (30 mL) and extracted with DCM (15 mL×3). The combined organic layers were washed with brine (30 mL), dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (Biotage; 12 g AgelaSilica Flash Column, 3% EtOAc/petroleum ether gradient elution @ 30 mL/min) to give intermediate 53d-1. LC-MS (ESI): m/z 403.5 [M+H] ⁺ .

Step E - Synthesis of Intermediates 51e-1a and 51e-1b To a solution of intermediate 51d-1 (930 mg, 2.311 mmol) in THF (20 mL) and H ₂ O (4 mL) was added osmium (VIII) oxide (58.7 mg, 0.231 mmol). The reaction was stirred at 0°C for 15 minutes. Then 4-methyl-morpholine 4-oxide (541 mg, 4.62 mmol) was added. The reaction was stirred at 24°C for 18 hours, and then saturated Na ₂ SO ₃ solution (30 mL) was added at 0°C with stirring. The resulting mixture was extracted with 9:1 DCM/MeOH (20 mL×3). The combined organic layers were dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (Biotage; 12 g Agela Silica Flash Column, 60% EtOAc/petroleum ether gradient elution @ 30 mL/min) to afford the product as a mixture of stereoisomers. LC-MS (ESI): m/z LC-MS (ESI): m/z 437.4 [M+H] ⁺ . The mixture of stereoisomers was further separated by SFC (column: DAICEL CHIRALPAK AS (250 mm×30 mm, 10 um); conditions: 0.1% NH ₃ ·H ₂ O EtOH; start B 20, end B 20; flow rate (mL/min) 60; injection 130) to give intermediate 51e-1a (first eluting stereoisomer, LC-MS (ESI): m/z 437.2 [M+H] ⁺ ) and intermediate 51e-1b (second eluting stereoisomer, LC-MS (ESI): m/z 437.3 [M+H] ⁺ ).

Step F - Synthesis of Intermediate 51f-1a To a solution of intermediate 51e-1a (261 mg, 0.598 mmol) in MeOH (6 mL) was added palladium on carbon (127 mg, 0.120 mmol, 10 wt.%). The reaction was stirred at 30 °C under _H2 atmosphere (15 psi) for 16 hours and then filtered. The filtrate was concentrated to give intermediate 51f-1a, which was used in the next step without further purification. LC-MS (ESI): m/z 257 [M+H] ⁺ .

Step G - Synthesis of Intermediate 51g-1a To a stirred mixture of Intermediate 51f-1a (165 mg, 0.644 mmol) and Intermediate 3c (294 mg, 0.631 mmol) in MeCN (4.0 mL) was added potassium acetate (190 mg, 1.932 mmol) and acetic acid (155 mg, 2.58 mmol). The reaction was stirred at 80 °C for 20 min, then diluted with H ₂ O (20 mL) and extracted with EtOAc (10 mL×3). The combined organic layers were washed with brine (30 mL), dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo to give Intermediate 51g-1a, which was used in the next step without further purification. LC-MS (ESI): m/z 675.6 [M+H] ⁺ .

Step H - Synthesis of Intermediate 51h-1a To a solution of intermediate 51g-1a (430 mg, 0.637 mmol) in 5:1 MeOH/H ₂ O (4 mL) was added K ₂ CO ₃ (370 mg, 2.68 mmol). The reaction was stirred at 22° C. for 3 hours and then filtered. The filtrate was concentrated in vacuo to afford intermediate 51h-1a, which was used in the next step without further purification. LC-MS (ESI): m/z 579.5 [M+H] ⁺ .

Step I - Synthesis of intermediate 51i-1a To a solution of intermediate 51h-1a (350 mg, 0.605 mmol) in 1 mL DCM was added aqueous HCl (12 N, 2 mL). The reaction was stirred at 22°C for 30 minutes, and then the solvent was removed in vacuo. The resulting residue was purified by reverse phase HPLC (Biotage; 20 g Agela C18, 20-35 μm, 0-20% gradient MeCN/H ₂ O (0.5% TFA) elution @ 50 mL/min) to afford intermediate 51i-1a. LC-MS (ESI): m/z 422.8 [M+H] ⁺ .

Step J - Synthesis of Compounds 94 and 95 To a solution of intermediate 51i-1a (200 mg, 0.473 mmol) in 4:1 MeOH/DMA (3 mL) was added intermediate 5 (172 mg, 0.473 mmol). The reaction was stirred at 28°C for 16 hours and then filtered. The filtrate was purified by reverse phase HPLC (column: Boston Uni C18 40×150×5um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 11; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1) to give a crude product. The crude product was further purified by reverse phase HPLC (Waters Xselect C18 150×19 mm×5 um; conditions: water (0.1% TFA)-ACN; start B 0, end B13; gradient time (min) 25; 100% B retention time (min) 2; flow rate (mL/min) 20; injection 4) to give the product as a TFA salt. The TFA salt was dissolved in H ₂ O (3.0 mL) and purified by preparative HPLC (column: Welch Xtimate C18 150×25 mm×5 um; conditions: water (0.225% FA)-ACN; start B 0, end B18; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 3) to give compound 94 as a formate salt. LC-MS (ESI): m/z 769.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O + CD ₃ CN)δ:7.39-7.31(m,2H),6.87(d,J＝8.6Hz,1H),6.78(s,1H),4.61(s,1H),4.60-4.29(m,2H),3.95-3.80(m,1H),3.47-3.34(m,2H),2.96-2.70(m,4H),2.56-2.40(m,2H),2.12-2.01(m,1H)1.92-1.83(m,2H),1.81-1.60(m,1H)1.50(s,3H),1.42(s,3H),1.25(s,3H).

Compound 95 was prepared from intermediate 51e-1b according to the procedures in step F to step J of Example 71. LC-MS (ESI): m/z 769.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.38-7.29 (m, 2H), 6.87 (d, J=8.2 Hz, 1H), 6.78 (s, 1H), 4.60 (s, 1H), 4.45-4.30 (m, 2H), 3.95-3.81 (m, 1H) 3.47-3.37 (m, 2H), 2.95-2.70 (m, 4H), 2.56 (br dd, J=6.1, 13.9 Hz, 1H), 2.44 (br dd, J = 6.7, 13.7 Hz, 1H), 2.12-2.02 (m, 1H), 1.92-1.82 (m, 2H), 1.80-1.61 (m, 1H), 1.50 (s, 3H), 1.42 (s, 3H), 1.25 (s, 3H). *Each compound is a single diastereomer; the stereochemistry of the *-marked carbon center is not specified.

Example 72: Preparation of Intermediates 52e-1 and 52e-2

Step A - Synthesis of intermediate 52a To a solution of intermediate 51a-2 (3.27 g, 9.36 mmol) in MeOH (42 mL) and H ₂ O (10.50 mL) was added sodium hydroxide (1.684 g, 42.1 mmol). The reaction mixture was stirred at 75° C. for 4.5 hours and then concentrated in vacuo. The resulting residue was diluted with H ₂ O (20 mL) and the pH was adjusted to pH 2-3 with aqueous HCl (2N). The resulting mixture was extracted with EtOAc (30 mL×3), and the combined organic layers were dried over anhydrous Na ₂ SO ₄ and filtered. The filtrate was concentrated in vacuo to give intermediate 52a, which was used in the next step without further purification. LC-MS (ESI): m/z 336.4 [M+H] ⁺ . ¹ H NMR (400 MHz, CD ₃ OD) δ: 7.62-7.42 (m, 10H), 5.84-5.59 (m, 1H), 5.29-5.03 (m, 2H), 4.25 (s, 4H), 4.02-3.89 (m, 1H), 2.57-2.49 (m, 2H), 2.46 (d, J=7.4 Hz, 2H), 2.26-2.16 (m, 2H).

Step B - Synthesis of Intermediate 52b To a solution of intermediate 52a (3.18 g, 9.48 mmol) in toluene (25 mL) and THF (25 mL) stirred at 0°C was added TEA (3.96 mL, 28.4 mmol) and diphenylphosphoryl azide (3.06 mL, 14.22 mmol). The mixture was stirred at 20°C under _N2 atmosphere for 1 hour and then at 45°C for 2 hours. The reaction temperature was then raised to 80°C and 2-(trimethylsilyl)ethanol (3.66 mL, 37.9 mmol) was added. The reaction was stirred at 80°C for 16 hours and then the solvent was removed in vacuo. The resulting residue was purified by reverse phase HPLC (Biotage; 20 g Agela, C18, 20-35 μm, 65% MeCN/ _H2O (0.5% TFA) gradient elution @ 50 mL/min) to afford intermediate 52b. LC-MS (ESI): m/z 451.9 [M+H] ⁺ . ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.48-7.38 (m, 10H), 5.82-5.56 (m, 1H), 5.19-5.03 (m, 2H), 4.08-3.98 (m, 4H), 4.01-3.82 (m, 2H), 3.27-3.16 (m, 1H), 3.04-2.91 (m, 2H), 2.51 (br d, J=7.1 Hz, 2H), 2.37-2.27 (m, 2H), 0.94-0.87 (m, 2H), 0.00 (s, 9H).

Step C - Synthesis of Intermediates 52c-1 and 52c-2 To a stirred solution of intermediate 52b (2.8 g, 6.21 mmol) in THF (35 mL) and H ₂ O (7.00 mL) at 0°C was added osmium (VIII) oxide (0.160 g, 0.629 mmol). The reaction was stirred at 0°C for 15 minutes, then 4-methylmorpholine 4-oxide (1.46 g, 12.46 mmol) was added. The reaction was then stirred at 20°C for 16 hours, then saturated aqueous Na ₂ SO ₃ solution (30 mL) was added at 0°C with stirring, and extracted with 9:1 DCM/MeOH (30 mL×3). The combined organic layers were dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (Biotage; 12 g Agela Silica Flash Column, 60% EtOAc/petroleum ether gradient elution @ 30 mL/min) to afford the product as a mixture of stereoisomers. The mixture of stereoisomers was further separated by SFC (column: DAICEL CHIRALCEL OD (250 mm×50 mm, 10 um); conditions: 0.1% NH ₃ ·H ₂ O/IPA; start B 30%, end B 30%; flow rate (mL/min) 200; injection 120) to afford pure intermediate 52c-1 (first eluting stereoisomer, LC-MS (ESI): m/z 485.8 [M+H] ⁺ ) and impure intermediate 52c-2 (second eluting stereoisomer). Impure intermediate 52c-2 was further purified by a second SFC (column: DAICELCHIRALCEL OD-H (250 mm×30 mm, 5 um); condition: 0.1% NH ₃ ·H ₂ O/IPA; start B 30, end B 30; flow rate (mL/min) 60; injection 150) to give pure intermediate 52c-2. LC-MS (ESI): m/z 485.8 [M+H] ⁺ .

Step D - Synthesis of Intermediate 52d-1 To a solution of intermediate 52c-1 (585 mg, 1.207 mmol) in MeOH (10 mL) was added Pd/C (257 mg, 0.241 mmol, 10 wt.%), and the mixture was stirred at 30° C. under H ₂ atmosphere (15 psi) for 16 hours. The reaction mixture was then filtered and the filtrate was concentrated in vacuo to afford intermediate 52d-1, which was used in the next step without further purification. LC-MS (ESI): m/z 305.2 [M+H] ⁺ .

Step E - Synthesis of Intermediates 52e-1 and 52e-2 To a stirred mixture of Intermediate 52d-1 (380 mg, 0.749 mmol) and Intermediate 3c (332 mg, 0.711 mmol) in MeCN (6.0 mL) was added acetic acid (0.171 mL, 3.00 mmol). The reaction was stirred at 80 °C for 20 min, then diluted with H ₂ O (30 mL) and extracted with EtOAc (15 mL×3). The combined organic layers were dried over anhydrous Na ₂ SO ₄ and filtered. The filtrate was concentrated in vacuo to give Intermediate 52e-1, which was used in the next step without further purification. LC-MS (ESI): m/z 723.9 [M+H] ⁺ .

Intermediate 52e-2 was prepared from Intermediate 52c-2 according to the procedures in Step D and Step E of Example 72. LC-MS (ESI): m/z 723.3 [M+H] ⁺ .

Example 73: Preparation of Compounds 96 and 97

(S)-2-((R)-6-(N-((1R,3S)-3-amino-3-((S)-2,3-dihydroxypropyl)cyclobutyl)-carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1S,3S)-3-amino-3-((R)-2,3-dihydroxypropyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid*

According to the procedure of step C to step D of Example 53, compounds 96 and 97 were prepared from the corresponding intermediate 52e-1 and intermediate 52e-2.

Compound 96: LC-MS (ESI): m/z 769.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O and CD ₃ CN)δ:7.44-7.34(m,2H),6.84(d,J＝8.2Hz,1H),6.79(s,1H),4.59(s,1H),4.35-4.33(m,1H),4.15-4.01(m,1H),3.97-3.82(m,1H),3.50-3.38(m,2H),2.90-2.79(m,1H),2.55-2.67(m,3H),2.56-2.47(m,2H),2.08-2.00(m,1H),1.90-1.83(m,2H),1.74-1.56(m,1H),1.48(s,3H),1.42(s,3H),1.24(s,3H)

Compound 97: LC-MS (ESI): m/z 769.3 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ +D ₂ O) δ: 7.45 (s, 1H), 7.40 (br d, J=9.0 Hz, 1H), 6.81 (d, J=8.6 Hz, 1H), 6.73 (s, 1H), 4.56 (s, 1H), 4.26 (br d, J = 11.7 Hz, 1H), 4.12-4.05 (m, 1H), 3.85-3.74 (m, 1H), 3.39-3.25 (m, 2H), 2.86-2.73 (m, 1H), 2.71-2.54 (m, 4H), 2.47-2.38 (m, 1H), 1.96-1.78 (m, 2H), 1.78-1.67 (m, 1H), 1.41 (s, 3H), 1.55-1.35 (m, 1H), 1.36 (s, 3H), 1.21 (s, 3H). *Each compound is a single diastereomer; the stereochemistry of the *-marked carbon center is not specified.

Example 74: Preparation of Intermediates 53e-cis-1, 53e-cis-2, 53e-trans-1 and 53e-trans-2

Step A - Synthesis of Intermediate 53a To a solution of 3-(dibenzylamino)-cyclobutane-1-carboxylic acid methyl ester (8 g, 25.9 mmol) in THF (130 mL) at -60°C was added LDA (38.8 mL, 78 mmol, 2M THF/heptane solution). The reaction was stirred at -60°C for 30 minutes, and then a solution of 2-(benzyloxy)acetaldehyde (5.82 g, 38.8 mmol) was added dropwise at -60°C. The reaction was stirred at 0°C for 1.5 hours, then diluted with water (90 mL) and extracted with ethyl acetate (70 mL x 3). The combined organic layers were washed with brine (80 mL), dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated in vacuo. The residue was purified by flash silica gel chromatography. 40g The crude product was purified by silica flash column, 0-30% ethyl acetate/petroleum ether gradient elution @ 45 mL/min) to afford intermediate 53a. LC-MS (ESI): m/z 460.5 [M+H] ⁺ .

Step B - Synthesis of Intermediate 53b To a stirred solution of intermediate 53a (7 g, 15.23 mmol) in DMF (30 mL) at 0°C was added NaH (0.731 g, 18.28 mmol, 60% in mineral oil). The reaction mixture was stirred at 0°C for 30 minutes, and then (bromomethyl)benzene solution (3.13 g, 18.28 mmol) was added dropwise at 0°C. The reaction was warmed to 25°C and stirred at 25°C for 1 hour. The reaction mixture was then diluted with water (100 mL) and extracted with ethyl acetate (80 mL x 3). The combined organic layers were washed with brine (70 mL), dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated in vacuo. The residue was purified by flash silica gel chromatography ( 40g The crude product was purified by silica flash column, 0-30% ethyl acetate/petroleum ether gradient elution @ 45 mL/min) to afford intermediate 53b, which was used in the next step without further purification. LC-MS (ESI): m/z 550.2 [M+H] ⁺ .

Step C - Synthesis of Intermediate 53c To a solution of intermediate 53b (3.7 g, 6.73 mmol) in MeOH (30 mL) and water (10 mL) was added NaOH (1.615 g, 40.4 mmol). The reaction was stirred at 80 °C for 12 hours and then concentrated in vacuo. The resulting residue was diluted with water (40 mL) and the pH was adjusted to pH 3 with HCl (1 M). The mixture was extracted with ethyl acetate (80 mL x 3), and the combined organic layers were washed with brine (90 mL), dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo to give intermediate 53c, which was used in the next step without further purification. LC-MS (ESI): m/z 536.4 [M+H] ⁺ .

Step D - Synthesis of Intermediates 53d-cis-1, 53d-cis-2, 53d-trans-1 and 53d-trans-2 To _a solution of intermediate 53c (3 g, 5.60 mmol) in THF (30 mL) and toluene (30 mL) was added TEA (2.342 mL, 16.80 mmol) and diphenylphosphoryl azide (1.448 mL, 6.72 mmol) at 25 °C under N2 atmosphere. The reaction mixture was stirred at 65 °C for 2 hours, and then 2-(trimethylsilyl)-ethanol (8.03 mL, 56.0 mmol) was added at 65 °C. The reaction was stirred at 90 °C for 12 hours, and then diluted with water (50 mL) and extracted with ethyl acetate (30 mL x 3). The combined organic layers were washed with brine (50 mL), dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated in vacuo. The residue was purified by flash silica gel chromatography ( 40g The crude product was purified by silica flash column, 30% ethyl acetate/petroleum ether gradient elution @ 45 mL/min) to obtain the product as a mixture of stereoisomers. LC-MS (ESI): m/z 651.3 [M+H] ⁺ . The mixture of stereoisomers was purified by SFC (DAICELCHIRALCEL OD (250 mm×50 mm, 10 um); conditions: 0.1% NH ₃ ·H ₂ O/MeOH; start B 35%, end B 35%; flow rate (mL/min) 200; injection 180) to obtain the trans stereoisomer and the cis stereoisomer.

The enantiomers of the trans -stereoisomer were further separated by SFC (DAICEL CHIRALPAK IG (250 mm×30 mm, 10 um); conditions: 0.1% NH ₃ ·H ₂ O/MeOH; start B 35%, end B 35%; flow rate (mL/min) 200; injection 180) to give intermediate 53d - trans -1 (first eluting isomer) and intermediate 53d - trans -2 (second eluting isomer), respectively. The enantiomers of the cis stereoisomer were further separated by SFC (DAICEL CHIRALPAK AD (250 mm×50 mm, 10 um); conditions: 0.1% NH ₃ ·H ₂ O/EtOH; start B 30%, end B 30%; flow rate (mL/min) 200; injection 120) to give intermediate 53d-cis-1 (first eluting isomer) and intermediate 53d-cis-2 (second eluting isomer), respectively.

Intermediate 53d-trans-1: LC-MS (ESI): m/z 651.3 [M+H] ⁺ . ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.45-7.11 (m, 20H), 4.83 (br s, 1H), 4.76-4.53 (m, 2H), 4.51-4.40 (m, 2H), 4.11-3.99 (m, 2H), 3.94-3.81 (m, 1H), 3.72-3.61 (m, 1H), 3.61-3.51 (m, 1H), 3.43 (br s, 4H), 3.42-3.24 (m, 1H), 2.59-2.44 (m, 1H), 2.37-2.23 (m, 1H), 2.21-2.09 (m, 1H), 2.03-1.84 (m, 1H), 0.98-0.84 (m, 2H), 0.00 (s, 9H)

Intermediate 53d-trans-2: ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.44-7.13 (m, 20H), 4.83 (br s, 1H), 4.52-4.77(m, 2H), 4.54-4.39(m, 2H), 4.10-4.00(m, 2H), 3.92-3.78(m, 1H), 3.73-3.61(m, 1H), 3.57-3.48(m, 1H), 3.48-3.37(m, 4H), 3.37-3.20(m, 1H), 2.61-2.38(m, 1H), 2.37-2.24(m, 1H), 2.22-2.13(m, 1H), 2.04-1.85(m, 1H), 0.99-0.82(m, 2H), 0.00(s, 9H).

Intermediate 53d-cis-1: LC-MS (ESI): m/z 651.2 [M+H] ⁺ . ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.47-7.13 (m, 20H), 5.00 (br s, 1H), 4.79 (d, J=11.7 Hz, 1H), 4.64-4.42 (m, 3H), 4.12-3.99 (m, 2H), 3.79-3.67 (m, 2H), 3.64-3.56 (m, 1H), 3.52-3.36 (m, 4H), 3.08-2.87 (m, 1H), 2.56-2.35 (m, 3H), 2.06-1.91 (m, 1H), 0.99-0.85 (m, 2H), 0.00 (s, 9H).

Intermediate 53d-cis-2: ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.47-7.13 (m, 20H), 5.00 (br s, 1H), 4.79 (d, J=11.7 Hz, 1H), 4.64-4.42 (m, 3H), 4.12-3.99 (m, 2H), 3.78-3.65 (m, 2H), 3.64-3.56 (m, 1H), 3.52-3.36 (m, 4H), 3.07-2.92 (m, 1H), 2.56-2.35 (m, 3H), 2.11-1.90 (m, 1H), 0.99-0.85 (m, 2H), 0.00 (s, 9H).

Step E - Synthesis of Intermediates 53e-cis-1, 53e-cis-2, 53e-trans-1 and 53e-trans- ₂ To a solution of intermediate 53d-trans-1 (300 mg, 0.461 mmol) in MeOH (10 mL) and acetic acid (2.5 mL) was added 10 wt.% Pd/C (98 mg, 0.092 mmol). The reaction mixture was stirred at 20°C and 15 psi of H2 for 12 hours, filtered, and the filtrate was concentrated in vacuo to give the crude intermediate 53e-trans-1. This material was used in subsequent reactions without further purification. LC-MS (ESI): m/z 291.3 [M+H] ⁺ .

Intermediates 53e-cis-2, 53e-trans-1 and 53e-trans-2 were prepared from corresponding intermediates 53d-cis-2, 53d-trans-1 and 53d-trans-2 according to the procedure of Example 74. LC-MS (ESI): m/z 291.3 [M+H] ⁺ .

Example 75: Preparation of Compounds 98-101

(S)-2-((R)-6-(N-((1S,3R)-3-amino-3-((S)-1,2-dihydroxyethyl)cyclobutyl)-carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid, (S)-2-((R)-6-(N-((1R,3R)-3-amino-3-((R)-1,2-dihydroxyethyl)cyclobutyl)-carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid, (S)-2-((R)-6-(N-((1S,3S)-3-amino-3-((R)-1,2-dihydroxyethyl)cyclobutyl)-carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1R,3S)-3-amino-3-((S)-1,2-dihydroxyethyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid*

According to step B to step D of example 53, compounds 98, 99, 100 and 101 were prepared from the corresponding intermediates 53e-trans-1, 53e-trans-2, 53e-cis-1 and 53e-cis-2.

Compound 98: LC-MS (ESI): m/z 755.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.35-7.26 (m, 2H), 6.84 (d, J=8.6 Hz, 1H), 6.78 (s, 1H), 4.61 (s, 1H), 4.42-4.29 (m, 2H), 3.82 (t, J=4.1 Hz, 1H), 3.74-3.61 (m, 2H), 2.89-2.69 (m, 4H), 2.65-2.49 (m, 2H), 2.17-2.05 (m, 1H), 1.82-1.63 (m, 1H), 1.53 (s, 3H), 1.43 (s, 3H), 1.25 (s, 3H).

Compound 99: LC-MS (ESI): m/z 755.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.38-7.28 (m, 2H), 6.86 (d, J=8.6 Hz, 1H), 6.78 (s, 1H), 4.59 (s, 1H), 4.42-4.30 (m, 2H), 3.82 (t, J=4.1 Hz, 1H), 3.74-3.62 (m, 2H), 2.87-2.69 (m, 4H), 2.64-2.50 (m, 2H), 2.14-2.03 (m, 1H), 1.79-1.63 (m, 1H), 1.50 (s, 3H), 1.42 (s, 3H), 1.24 (s, 3H).

Compound 100: LC-MS (ESI): m/z 755.4 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.43-7.35 (m, 2H), 6.85 (d, J=8.6 Hz, 1H), 6.78 (s, 1H), 4.60 (s, 1H), 4.33 (br d, J = 10.6 Hz, 1H), 4.13-3.97 (m, 1H), 3.81 (t, J = 4.4 Hz, 1H), 3.74 (d, J = 3.9 Hz, 2H), 2.99-2.81 (m, 2H), 2.81-2.66 (m, 2H), 2.60-2.39 (m, 2H), 2.10-1.99 (m, 1H), 1.74-1.60 (m, 1H), 1.48 (s, 3H), 1.42 (s, 3H), 1.24 (s, 3H).

Compound 101: LC-MS (ESI): m/z 755.4 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.43-7.35 (m, 2H), 6.85 (d, J=8.6 Hz, 1H), 6.78 (s, 1H), 4.60 (s, 1H), 4.33 (br d, J = 10.6 Hz, 1H), 4.12-4.00 (m, 1H), 3.81 (t, J = 4.4 Hz, 1H), 3.74 (d, J = 3.9 Hz, 2H), 2.97-2.85 (m, 2H), 2.85-2.67 (m, 2H), 2.63-2.39 (m, 2H), 2.10-1.98 (m, 1H), 1.74-1.55 (m, 1H), 1.48 (s, 3H), 1.42 (s, 3H), 1.24 (s, 3H). *Each compound is a single diastereomer; the stereochemistry of the *-marked carbon center is not specified.

Example 76: Preparation of Intermediates 54d-1 and 54d-2

Step A - Synthesis of Intermediate 54a A solution of 4-(dibenzylamino)cyclohexane-1-carboxylic acid (10 g, 30.9 mmol), DIEA (16.20 mL, 93 mmol) and HATU (17.63 g, 46.4 mmol) in DMF (155 mL) was stirred at 25 °C for 0.5 h, then the reaction mixture was cooled to 0 °C and methylamine hydrochloride (2.505 g, 37.1 mmol) was added. The reaction was stirred at 25 °C for 2 h, then diluted with water (500 mL) and extracted with EtOAc (150 mL x 3). The combined organic layers were washed with brine (600 mL x 2), dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo to give Intermediate 54a, which was used in the next step without further purification. LC-MS (ESI): m/z 336.9 [M+H] ⁺ .

Step B-Synthesis of Intermediate 54b To a solution of intermediate 54a (5 g, 14.86 mmol) in THF (150 mL) was added LAH (2.3 g, 60.6 mmol) at 0°C. The reaction was stirred at 85°C for 16 hours. The reaction was then cooled to room temperature and quenched by sequentially adding water (2.3 mL), NaOH aqueous solution (4.6 mL, 1 N) and water (6.9 mL). The resulting mixture was filtered and the filtrate was concentrated in vacuo to give intermediate 54b. LC-MS (ESI): m/z 323.1 [M+H] ⁺ .

Step C - Synthesis of Intermediates 54c-1 and 54c-2 A solution of (Boc) ₂ O (6.90 mL, 29.7 mmol), Et ₃ N (6.21 mL, 44.6 mmol) and intermediate 54b (4.79 g, 14.85 mmol) in DCM (100 mL) was stirred at 23° C. for 16 hours. The reaction solution was directly purified by silica gel chromatography using petroleum ether/EtOAc (5:1) as eluent to give a mixture of stereoisomers. LC-MS (ESI): m/z 423.5 [M+H] ⁺ . The mixture of stereoisomers was further separated by SFC (column: DAICEL CHIRALPAK AD (250 mm x 50 mm, 10 um); conditions: 0.1% NH ₃ ·H ₂ O/EtOH; start B 20%, end B 20%; flow rate (mL/min) 200; injection 120) to give intermediate 54c-1 (first eluting isomer) and intermediate 54c-2 (second eluting isomer), respectively.

Intermediate 54c-1: ¹ H NMR (400 MHz, CD ₃ OD) δ: 7.37-7.29 (m, 4H), 7.26 (t, J=7.5 Hz, 4H), 7.21-7.12 (m, 2H), 3.63 (s, 4H), 3.38-3.26 (m, 2H), 2.79 (br s, 3H), 2.57-2.44 (m, 1H), 1.97-1.84 (m, 1H), 1.73-1.55 (m, 6H), 1.45 (s, 9H), 1.41-1.25 (m, 2H).

Intermediate 54c-2: ¹ H NMR (400 MHz, CD ₃ OD) δ: 7.36-7.29 (m, 4H), 7.24 (t, J=7.5 Hz, 4H), 7.19-7.12 (m, 2H), 3.58 (s, 4H), 3.01-1.91 (m, 2H), 2.79 (br s, 3H), 2.50-2.38 (m, 1H), 1.90 (br d, J=12.0 Hz, 2H), 1.70 (br d, J=12.7 Hz, 2H), 1.58-1.48 (m, 1H), 1.41 (br s, 9H), 1.39-1.32 (m, 2H), 0.89-0.74 (m, 2H).

Step D - Synthesis of Intermediates 54d-1 and 54d-2 A mixture of intermediate 54c-1 (700 mg, 1.656 mmol) and Pd/C (176 mg, 0.166 mmol, 10 wt.%) in EtOH (20 mL) was stirred for 16 hours at 25° C. under a hydrogen atmosphere (15 psi). The reaction mixture was then filtered and the filtrate was concentrated in vacuo to afford intermediate 54d-1, which was used in the next step without further purification. LC-MS (ESI): m/z 243.1 [M+H] ⁺ .

Intermediate 54d-2 was prepared from Intermediate 54c-2 according to the procedure in Step D of Example 76. LC-MS (ESI): m/z 243.1 [M+H] ⁺ .

Example 77: Preparation of Compounds 102 and 103

(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1s,4S)-4-((methylamino)methyl)-cyclohexyl)amidino)chroman-2-yl)propanoic acid and (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1r,4R)-4-((methylamino)methyl)cyclohexyl)amidino)chroman-2-yl)propanoic acid

According to the procedure of step A to step C of Example 32, compounds 102 and 103 were prepared starting from the corresponding intermediate 54d-1 and intermediate 54d-2.

Compound 102: LC-MS (ESI): m/z 751.3 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ +D ₂ O) δ: 7.47-7.33 (m, 2H), 6.91 (d, J=8.6 Hz, 1H), 6.73 (s, 1H), 4.58 (s, 1H), 4.39 (br d, J=12.1 Hz, 1H), 3.74-3.66 (m, 1H), 2.89-2.68 (m, 4H), 2.50 (s, 3H), 2.09-1.95 (m, 1H), 1.93-1.76 (m, 1H), 1.75-1.49 (m, 9H), 1.46 (s, 3H), 1.38 (s, 3H), 1.22 (s, 3H).

Compound 103: LC-MS (ESI): m/z 751.3 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ +D ₂ O) δ: 7.45-7.31 (m, 2H), 6.93 (d, J=8.6 Hz, 1H), 6.75 (s, 1H), 4.60 (s, 1H), 4.36 (br d, J=11.7 Hz, 1H), 3.54-3.43 (m, 1H), 2.90-2.61 (m, 4H), 2.50 (br s, 3H), 2.12-1.98 (m, J = 9.8 Hz, 1H), 1.91-1.68 (m, 4H), 1.69-1.48 (m, 2H), 1.51 (s, 3H), 1.39 (s, 3H), 1.35-1.1.18 (m, 2H), 1.24 (s, 3H), 1.13-0.95 (m, 2H).

Example 78: Preparation of Intermediates 55b-1 to 55b-4

Step A - Synthesis of Intermediates 55a-1 to 55a-4 To a flask charged with tert-butyl (4-aminocycloheptyl) carbamate (1.1 g, 4.8 mmol) was added DCM (48 mL). The mixture was cooled to 0 °C under _N2 , Hunig's base (1.7 mL, 9.6 mmol) was added, followed by a solution of CBZ-Cl (0.74 mL, 5.1 mmol) in DCM (6 mL) dropwise. The reaction was stirred at 0 °C for 15 min and then quenched with ice-cold saturated _NH4Cl solution (30 mL). The aqueous layer was extracted with DCM (20 mL). The combined organic layers were dried over anhydrous _MgSO4 , filtered, and the filtrate was concentrated in vacuo. The resulting residue was purified by Isco silica gel column (120 g), eluting with 0-70% EtOAc/hexane (gradient) over 12 CV to give the product as a mixture of stereoisomers. LC-MS: m/z 385.4 [M+Na] ⁺ . The mixture of stereoisomers was further separated by SFC (OJ-H (2×25 cm), 15% MeOH/CO ₂ (100 bar), 70 mL/min, 220 nm) to obtain each enantiomerically pure intermediate as follows: intermediate 55a-1, first peak on chiral column, LC-MS: m/z 363.3 [M+H] ⁺ ; intermediate 55a-2, second peak on chiral column, LC-MS: m/z 363.3 [M+H] ⁺ ; intermediate 55a-3, third peak on chiral column, LC-MS: m/z 363.2 [M+H] ⁺ ; and intermediate 55a-4, fourth peak on chiral column, LC-MS: m/z 363.4 [M+H] ⁺ .

Step B - Synthesis of Intermediates 55b-1 to 55b-4 A flask containing intermediate 55a-2 (310 mg, 0.86 mmol) and Pd/C (45 mg, 0.043 mmol, 10 wt.%) was evacuated and refilled with _N2 (3x). MeOH (8.6 mL) was then added and the reaction vessel was evacuated and refilled with _H2 (3x). The reaction was carried out under a hydrogen balloon (1 atm) and then filtered. The resulting filter cake was rinsed with MeOH. The filtrate was concentrated in vacuo to afford intermediate 57b-2.

Intermediates 55b-1, 55b-3 and 55b-4 were prepared according to the procedure of Example 78, step B, starting from the corresponding intermediates 55a-1, 55a-3 and 55a-4.

Intermediate 55b-1, LC-MS: m/z 229.3 [M+H] ⁺ .

Intermediate 55b-2, LC-MS: m/z 229.3 [M+H] ⁺ .

Intermediate 55b-3, LC-MS: m/z 229.4 [M+H] ⁺ .

Intermediate 55b-4, LC-MS: m/z 229.3 [M+H] ⁺ .

Example 79: Preparation of Compound 104

(S)-2-((R)-6-(N-((1R or S, 4S or R)-4-aminocycloheptyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid*

Step A - Synthesis of intermediate 56a To a mixture of intermediate 3c (937 mg, 1.6 mmol) and intermediate 55b-3 (360 mg, 1.6 mmol) in MeCN (15.8 mL) was added acetic acid (0.54 mL, 9.5 mmol). The reaction was stirred at 70°C for 4 hours, then cooled to room temperature and directly purified by reverse phase HPLC (Isco; column: C18 (150 g) starting from 2CV of 10% MeCN- _H2O (0.05% TFA), then 11CV of 10-100% (gradient) MeCN- _H2O (0.05% TFA)) to give intermediate 56a after freeze drying. LC-MS: m/z 647.3 [M+H] ⁺ .

Step B - Synthesis of Intermediate 56b A solution of intermediate 56a (570 mg, 0.75 mmol) in DCM (5 mL) and TFA (10 mL) was heated to 40°C and stirred for 90 minutes. The reaction mixture was then cooled to ambient temperature and concentrated in vacuo. The resulting residue was dried under high vacuum for 2 hours to afford intermediate 56b. LC-MS: m/z 391.2 [M+H] ⁺ .

Step C - Synthesis of Compound 104 Intermediate 56b (464 mg, 0.75 mmol), intermediate 5 (301 mg, 0.83 mmol) and molecular sieves The mixture of (～500mg) in MeOH (7.5mL) solution was stirred at room temperature for 18 hours. Then the mixture was filtered through a Celite ^TM pad, and the filtrate was concentrated in vacuo. The obtained residue was dissolved in water and purified by reversed-phase HPLC (Isco; C18-Aq 150g column) with a 0-30% MeCN (0.05% TFA)/water (0.05% TFA) gradient elution. The product fractions were collected and freeze-dried to obtain the title compound as a TFA salt. The TFA salt was further purified by reversed-phase HPLC (Isco; C18-Aq 50g column) with a 0-25% MeCN (0.1% FA)/water (0.1% FA) gradient elution. The product fractions were collected and freeze-dried to obtain the title compound as a formate. LC-MS: m/z 737.3 [M+H] ⁺ . ¹ H NMR (500 MHz, D ₂ O) δ: 7.54 (s, 1H), 7.51 (d, J=8.5 Hz, 1H), 7.04 (d, J=8.7 Hz, 1H), 7.01 (s, 1H), 4.60 (d, J=10.7 Hz, 1H), 3.96 (s, 1H), 3.56 (s, 1H), 3.04-2.91 (m, 2H), 2.34-2.28 (m, 1H), 2.28-2.14 (m, 4H), 2.00-1.91 (m, 1H), 1.91-1.75 (m, 6H), 1.69 (s, 3H), 1.59 (s, 3H), 1.38 (s, 3H). *Each compound is a single diastereomer; the stereochemistry of the *marked carbon center is not specified.

Example 80: Preparation of Compounds 105, 106 and 107

(S)-2-((R)-6-(N-((1R or S, 4S or R)-4-aminocycloheptyl)carbamimidyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid (the remaining three diastereomers of the structure)

According to the procedure of step A to step C of Example 79, compounds 105, 106 and 107 were prepared from the corresponding intermediates 55b-1, 55b-2 and 55b-4.

Compound 105: LC-MS: m/z 737.1 [M+H] ⁺ . ¹ HNMR (500 MHz, D ₂ O/CD ₃ CN＝4:1)δ:7.71(s,1H),7.71(d,J＝15.1Hz,1H),7.21(s,1H),7.21(d,J＝15.1Hz,1H),4.95(s,1H),4.12(s,1H),3.67(s,1H),3.23-3.08(m,2H),2.52-2.39(m,3H),2.25(s,3H),2.14(d,J＝11.8Hz,3H),1.99-1.89(m,1H),1.86(s,3H),1.82(d,J＝11.5Hz,1H),1.76(s,3H),1.70(d,J＝12.4Hz,1H),1.56(s,3H).

Compound 106: LC-MS: m/z 737.1 [M+H] ⁺ . ¹ HNMR (500 MHz, D ₂ O/CD ₃ CN＝4:1):δ:7.72(s,1H),7.72(d,J＝7.1Hz,1H),7.22(d,J＝7.1Hz,1H),7.18(s,1H),4.94(s,1H),4.11(s,1H),3.67(s,1H),3.22-3.05(m,2H),2.42(s,3H),2.25(s,3H),2.14(s,3H),1.89(d,J＝12.5Hz,1H),1.84(s,3H),1.81-1.79(m,1H),1.76(s,3H),1.69(d,J＝12.1Hz,1H),1.57(s,3H).

Compound 107: LC-MS: m/z 737.3 [M+H] ⁺ . ¹ H NMR (500 MHz, D ₂ O/CD ₃ CN＝4:1) δ: δ: 7.71 (s, 1H), 7.71 (d, J＝8.0 Hz, 1H), 7.21 (d, J＝8.0 Hz, 1H), 7.17 (s, 1H), 4.94 (s, 1H), 4.09 (s, 1H), 3.68 (s, 1H), 3.12-3.04 (m, 2H), 2.48-2.40 (m, 1H), 2.40-2.30 (m, 4H), 2.13-2.04 (m, 1H), 2.04-1.88 (m, 6H), 1.84 (s, 3H), 1.76 (s, 3H), 1.57 (s, 3H).

Example 81: Preparation of Compounds 108-111

The following compounds were prepared according to the procedures in Example 79, Step A to Step C, starting from the appropriate commercially available enantiomerically pure mono-Boc protected diamine.

Example 82: Preparation of Compound 112

(S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)cyclobutyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 57a To a vial containing a mixture solution of cis-3-(Boc-aminomethyl)cyclobutylamine (86 mg, 0.429 mmol) in anhydrous acetonitrile (4 mL) was added Intermediate 3c (0.2 g, 0.429 mmol) and acetic acid (0.086 mL, 1.50 mmol). The reaction mixture was heated at 65°C for 3 hours. The reaction mixture was then cooled to ambient temperature and purified by reverse phase Isco Combiflash (C 18, 50 g column; 0-100% (gradient) water + 0.05% TFA/ACN + 0.05% TFA) to give the desired compound. LC-MS: m/z 619.8 [M+H] ⁺ .

Step B - Synthesis of Intermediate 57b To a vial containing Intermediate 57a (0.235 g, 0.38 mmol) was added 2:1 trifluoroacetic acid/anhydrous dichloromethane (6 mL) at ambient temperature. The reaction was stirred for 16 hours, then a solution of 4:1 toluene/MeOH (10 mL) was added and the reaction mixture was concentrated in vacuo. The resulting residue was azeotroped with 4:1 toluene/MeOH (10 mL) and dried under high vacuum to afford Intermediate 57b. LC-MS: m/z 363.2 [M+H] ⁺ .

Step C - Synthesis of Intermediate 57c To a vial containing Intermediate 57b (0.138 g, 0.381 mmol) and Intermediate 4 (0.177 g, 0.381 mmol) was added MeOH (5.0 mL) at ambient temperature. The reaction mixture was stirred for 6 hours and then concentrated in vacuo to afford Intermediate 57c, which was used in the next step without further purification. LC-MS: m/z 809.0 [M+H] ⁺ .

Step D-Synthesis of Compound 112 At ambient temperature, a mixture of 1:2 trifluoroacetic acid/anhydrous dichloromethane (6 mL) was added to a vial containing intermediate 57c (0.308 g, 0.381 mmol). The reaction mixture was stirred for 1 hour, then cooled to 0 ° C, and then ether (6 mL) was slowly added. The resulting solid was collected by centrifugation (1400 rpm) and purified by HPLC (Gilson, C18, 5um, OBD 30X150 mm, ACN+0.05% TFA/water+0.05% TFA, 0-40% gradient 18 minutes, 30 mL/min). The product fractions were collected, concentrated in vacuo, and the resulting aqueous layer was directly purified by Amberchrom CG161M column (26 g), washed with 9CV of (water + 0.1% FA), eluted with 3CV of 100% (MeCN + 0.1% FA), and then 3CV of 50% (MeCN + 0.1% FA) / (water + 0.1% FA). The product fractions were collected, concentrated in vacuo, and the resulting aqueous residue was freeze-dried to give compound 112 as a formate salt. LC-MS: m/z 709.4 [M + H] ⁺ . ¹ H NMR (500 MHz, 400 uL D ₂ O / 100 uLCD ₃ CN) δ: 7.59-7.55 (m, 2H), 7.08-7.07 (d, J = 5 Hz, 1H), 7.00 (s, 1H), 4.79 (s, 1H), 4.59-4.56 (m, 1H), 4.27-4.19 (m, 1H), 3.18-3.16 (d, J = 10 Hz, 2H), 3.02-2.94 (m, 2H), 2.86-2.78 (m, 1H), 2.58-2.50 (m, 1H), 2.26 (br, 1H), 2.15-2.04 (m, 3H), 1.90 (m, 1H), 1.69 (s, 3H), 1.61 (s, 3H), 1.42 (s, 3H).

Example 83: Preparation of Compounds 113 and 114

Using the procedure of Step A to Step D of Example 82, the following compounds were prepared from commercially available mono-Boc protected diamine.

Example 84: Preparation of Intermediates 58c-1 and 58c-2

Step A - Synthesis of Intermediate 58a To a solution of tert-butyl (7-oxospiro [3.5] nonan-2-yl) carbamate (500 mg, 1.974 mmol) in MeOH (8 mL) under _N2 was added benzylamine (0.432 mL, 3.95 mmol). The reaction was stirred at ambient temperature for 2 hours. Sodium cyanoborohydride (496 mg, 7.89 mmol) was then added portionwise and the reaction mixture was stirred at ambient temperature for 18 hours. The reaction mixture was then partitioned between ethyl acetate (100 mL) and water (100 mL). The organic layer was separated, washed with brine, dried over anhydrous _MgSO4 and filtered. The filtrate was concentrated in vacuo and the resulting residue was purified by silica gel chromatography (ISCO 80 g, eluted with 0-100% EtOAc/hexane (gradient)) to afford Intermediate 58a as a mixture of enantiomers. LC-MS: m/z 345.3 [M+H] ⁺ .

Step B - Synthesis of intermediate 58b-1 and intermediate 58b-2 The enantiomers of intermediate 58a (546 mg, 1.585 mmol) were further separated by chiral SFC (AD-H 250 mm column, 25% MeOH + 0.2% DIPA, 210 nm wavelength, injection volume 1.8 mL, flow rate 50 ml/min) to give intermediate 58b-1 (first eluting isomer, LC-MS: m/z 345.3 [M+H] ⁺ ) and intermediate 58b-2 (second eluting isomer, LC-MS: m/z 345.3 [M+H] ⁺ ), respectively.

Step C - Synthesis of intermediates 58c-1 and 58c-2 To a solution of intermediate 58b-1 (190 mg, 0.552 mmol) in MeOH (3 mL) was added Pd/C (58.7 mg, 0.055 mmol, 10 wt.%) and the reaction was stirred at ambient temperature under _H2 (1 atm) for 1 hour. The reaction mixture was then filtered and the filtrate was concentrated in vacuo to afford intermediate 58c-1 which was used in the next step without further purification. TLC: EtOAc/hexane 1/1, Rf=0.1.

Intermediate 58c-2 was prepared from intermediate 58b-2 according to the procedure of Step C of Example 84. TLC: EtOAc/hexane 1/1, Rf=0.1.

Example 85: Preparation of Compounds 115 and 116

(S)-2-((R)-6-(N-((2S,4s,7S)-2-aminospiro[3.5]nonan-7-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-( (R)-6-(N-((2R,4r,7R)-2-aminospiro[3.5]nonan-7-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid (stereochemistry of the center marked by * is not specified)

Compounds 115 and 116 were prepared from intermediate 58c-1 and intermediate 58c-2 according to the procedures in step A to step D of Example 82.

Compound 115: LC-MS: m/z 763.6 [M+H] ⁺ . ¹ HNMR (500 MHz, 400 uL D ₂ O/100 uL CD ₃ CN) δ: 7.62-7.58 (m, 2H), 7.13 (d, J=10 Hz, 1H), 7.03 (s, 1H), 4.85 (s, 1H), 4.60-4.56 (m, 1H), 3.97-3.88 (m, 1H), 3.71 (br s, 1H), 3.03 (br s, 2H), 2.52 (br s, 1H), 2.32 (br s, 2H), 2.20-2.17(m, 3H), 2.13-1.89(m, 8H), 1.73(s, 3H), 1.65(s, 3H), 1.49(s, 3H).

Compound 116: LC-MS: m/z 763.5 [M+H] ⁺ . ¹ HNMR (500 MHz, 400 uL D ₂ O/100 uL CD ₃ CN) δ: 7.57-7.53 (m, 2H), 7.09 (d, J=15 Hz, 1H), 7.01 (s, 1H), 4.80 (s, 1H), 4.60-4.56 (m, 1H), 3.90-3.84 (m, 1H), 3.67 (br s, 1H), 2.99 (br s, 2H), 2.47 (br s, 1H), 2.29 (br s, 2H), 2.17-2.14 (m, 3H), 2.08-1.83 (m, 8H), 1.69 (s, 3H), 1.62 (s, 3H), 1.44 (s, 3H).

Example 86: Preparation of Intermediates 59e-1 and 59e-2

Step A - Synthesis of Intermediate 59a To a mixture of tert-butyl (3-(aminomethyl)-3-methylcyclobutyl)carbamate (350 mg, 1.633 mmol) in DCM (5 mL) was added TEA (0.341 mL, 2.450 mmol) followed by benzyl chloroformate (0.281 mL, 1.960 mmol). The reaction mixture was stirred at ambient temperature for 18 hours, then diluted with DCM and washed with saturated aqueous NaHCO ₃ solution. The organic layer was separated, dried over anhydrous MgSO ₄ and filtered. The filtrate was concentrated in vacuo. The resulting residue was purified by silica gel chromatography (Isco, 40 g column, 0-50% EtOAc in hexanes, gradient) to afford Intermediate 59a as a mixture of stereoisomers. LC-MS: m/z 349.3 [M+H] ⁺ .

Step B - Synthesis of Intermediates 59b-1 and 59b-2 Intermediate 59a (420 mg, 1.205 mmol) was further separated by SFC (AD-H, 21X250 mm column, eluted with 15% IPA/ _CO2 , 100 bar, 220 nm wavelength, injection volume 0.3 mL, flow rate 60 mL/min) to give Intermediate 59b-1 (first eluting stereoisomer) and Intermediate 59b-2 (second eluting stereoisomer), respectively. LC-MS: m/z 349.3 [M+H] ⁺ .

Step C - Synthesis of Intermediate 59c-1 To a solution of intermediate 59b-1 (140 mg, 0.402 mmol) in DCM (5 mL) stirred at 0°C was added TFA (0.615 mL, 8.04 mmol). The reaction was stirred at 0°C for 1 hour. The reaction mixture was diluted with 30% toluene/MeOH (6 mL) and concentrated in vacuo to afford intermediate 59c-1, which was used in the next step without further purification. LC-MS: m/z 249.3 [M+H] ⁺ .

Step D - Synthesis of Intermediate 59d-1 To a mixture of intermediate 59c-1 (102 mg, 0.411 mmol) in anhydrous acetonitrile (4 mL) was added intermediate 3c (0.16 g, 0.343 mmol) and acetic acid (0.069 mL, 1.20 mmol). The reaction mixture was heated at 65 ° C for 1 hour. The reaction was then cooled to ambient temperature and purified by reverse phase HPLC (C18, 100 g column, 0-100% 0.05% TFA water/ACN, (gradient)) to give intermediate 59d-1. LC-MS: m/z 667.6 [M+H] ⁺ .

Step E - Synthesis of Intermediates 59e-1 and 59e-2 To a solution of intermediate 59d-1 (215 mg, 0.322 mmol) in EtOH (5 mL) was added Pd/C (30 mg, 10 wt.%, 50% humidity). The reaction mixture was stirred at ambient temperature under H ₂ (1 atm) for 1 hour. The reaction mixture was then filtered and the filtrate was concentrated in vacuo to afford intermediate 59e-1, which was used in the next step without further purification. LC-MS: m/z 533.5 [M+H] ⁺ .

Intermediate 59e-2 was prepared from Intermediate 59b-2 using the procedure from Step C to Step D of Example 86. LC-MS: m/z 533.4 [M+H] ⁺ .

Example 87: Preparation of Compounds 117 and 118

(S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)-3-methylcyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)-3-methylcyclobutyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid*

According to the procedure of step B to step D of Example 82, compounds 117 and 118 were prepared from intermediate 59e-1 and intermediate 59e-2.

Compound 117: LC-MS: m/z 723.6 [M+H] ⁺ . ¹ H NMR (500 MHz, 400 uL D ₂ O/100 uL CD ₃ CN) δ: 7.51-7.47 (m, 2H), 7.00-6.96 (m, 2H), 4.52-4.50 (m, 1H), 4.39-4.31 (m, 1H), 3.08 (s, 2H), 2.89 (br s, 2H), 2.47-2.42 (m, 2H), 2.21-2.16 (m, 2H), 2.07-2.04 (m, 2H), 1.85 (br s, 1H), 1.61 (s, 3H), 1.52 (s, 3H), 1.33 (s, 6H).

Compound 118: LC-MS: m/z 723.6 [M+H] ⁺ . ¹ HNMR (500 MHz, 400 uL D ₂ O/100 uL CD ₃ CN) δ: 7.56-7.53 (m, 2H), 7.06 (d, J=10 Hz, 1H), 6.99 (s, 1H), 4.77 (s, 1H), 4.58-4.55 (m, 1H), 4.30-4.26 (m, 1H), 3.20 (s, 2H), 2.95 (br s, 2H), 2.65 (br s, 2H), 2.21 (br s, 2H), 2.12-2.10 (m, 2H), 1.88 (br s,1H),1.67(s,3H),1.58(s,3H),1.40(s,3H),1.35(s,3H). *Each compound is a single diastereomer and the stereochemistry of the carbon marked by the * is not specified.

Example 88: Preparation of Intermediate 60i-1

Step A - Synthesis of Intermediate 60a NaH (0.568 g, 14.20 mmol) was added in one portion to a stirred mixture of methyltriphenylphosphonium bromide (5.07 g, 14.20 mmol) in DMSO (18 mL) at ambient temperature. The reaction mixture was stirred for 30 minutes and then tert-butyl(6-oxospiro[3.3]hept-2-yl)carbamate (2 g, 8.88 mmol) was added in one portion. The reaction mixture was stirred for 1.5 hours and then poured into a flask containing ~200 g of ice. _Et2O (150 mL) was added to the mixture followed by EtOAc (50 mL) and the mixture was stirred for 1 hour. The layers were then separated and the aqueous layer was extracted with 1: ₁ Et2O/EtOAc (100 mL). The organic layers were combined, washed with brine, dried over anhydrous magnesium sulfate and filtered. The filtrate was concentrated in vacuo. The resulting residue was dissolved in _CH2Cl2 and loaded onto a dry Biotage 120g silica gel column. The solvent was removed from the column by a stream of nitrogen. Gradient elution (0% to 50% EtOAc in hexanes) afforded intermediate 60a _. TLC: 50% EtOAc/hexanes, Rf=0.8.

Step B - Synthesis of Intermediate 60b Triethylamine hydrofluoride (2.92 mL, 17.91 mmol) was added to a stirred mixture of intermediate 60a (1.6 g, 7.16 mmol) in DCM (20 mL). The reaction was stirred at ambient temperature for 10 minutes, then a solution of N-bromosuccinimide (1.913 g, 10.75 mmol) in DCM (30 mL) was added dropwise. The reaction mixture was stirred at ambient temperature for 3 hours, then partitioned between DCM and saturated sodium thiosulfate solution with stirring for 1 hour. The layers were then separated and the aqueous layer was extracted with 1: ₁ Et2O/EtOAc (100 mL). The organic layers were combined, washed with brine, dried over _anhydrous magnesium sulfate, and filtered. The filtrate was concentrated in vacuo. The resulting residue was dissolved in _CH2Cl2 and loaded onto a dry Biotage 120 g silica gel column. The solvent was removed from the column by a stream of nitrogen. Gradient elution (0% to 50% EtOAc in hexanes) afforded intermediate 60b. TLC: 50% EtOAc/hexanes, Rf = 0.6.

Step C - Synthesis of Intermediate 60c A mixture of Intermediate 60b (1.93 g, 5.99 mmol) and _NaN3 (0.506 g, 7.79 mmol) in DMSO (10 mL) was stirred at 120°C for 18 hours. The reaction mixture was then partitioned between EtOAc (150 mL) and brine (150 mL). The layers were separated and the organic layer was washed with brine, dried over anhydrous _MgSO4 and filtered. The filtrate was concentrated in vacuo to afford Intermediate 60c. TLC: 50% EtOAc/hexanes, Rf=0.5.

Step D - Synthesis of Intermediate 60d To a stirred mixture of intermediate 60c (0.7 g, 2.462 mmol) in THF (12 mL) and water (10 mL) at room temperature was added polymer bound _PPh3 (3 mmol/g, 1.23 g, 3.69 mmol). The reaction mixture was stirred at room temperature overnight and then filtered. The filtrate was concentrated to give intermediate 60d which was used in the next step without further purification. TLC: 50% EtOAc/hexanes, Rf=0.1.

Step E - Synthesis of Intermediate 60e To a mixture of intermediate 60d (295 mg, 1.142 mmol) in DCM (5 mL) was added TEA (0.318 mL, 2.284 mmol) followed by benzyl chloroformate (0.246 mL, 1.713 mmol). The reaction mixture was stirred overnight at ambient temperature, then diluted with DCM and washed with saturated aqueous NaHCO ₃ solution. The organic phase was dried over anhydrous MgSO ₄ and filtered. The filtrate was concentrated in vacuo and the resulting residue was purified by silica gel chromatography (ISCO, 40 g column, gradient elution of 0-50% EtOAc in hexanes) to afford intermediate 60e as a mixture of enantiomers. LC-MS: m/z 393.3 [M+H] ⁺ .

Step F - Synthesis of Intermediate 60f-1 and Intermediate 60f-2 The enantiomers of intermediate 60e (247 mg, 0.629 mmol) were further separated by AD-H column (21×250 mm, co-solvent: 15% EtOH/CO ₂ , 210 nm wavelength, injection volume 1.5 mL, flow rate 5050 mL/min) to give intermediate 60f-1 (first eluting enantiomer) and intermediate 60f-2 (second eluting enantiomer). LC-MS: m/z 393.3 [M+H] ⁺ .

Step G - Synthesis of Intermediate 60g-1 To a stirred solution of intermediate 60f-1 (100 mg, 0.255 mmol) in DCM (4 mL) at 0°C was added TFA (0.39 mL, 5.1 mmol). The reaction was stirred at ambient temperature for 1 hour, then diluted with 30% toluene/MeOH (6 mL) and concentrated in vacuo to afford intermediate 60g-1, which was used in the next step without further purification. LC-MS: m/z 293.3 [M+H] ⁺ .

Step H - Synthesis of Intermediate 60h-1 To a vial containing a mixture of intermediate 60g-1 (75 mg, 0.257 mmol) in anhydrous acetonitrile (4 mL) was added intermediate 3c (0.10 g, 0.214 mmol) and acetic acid (0.043 mL, 0.75 mmol). The reaction mixture was heated at 65 ° C for 1 hour. The reaction was then cooled to ambient temperature and purified by reverse phase HPLC (ISCO, C18, 100 g column, eluted with 0-100% ACN + 0.05% TFA / water + 0.05% TFA gradient) to give intermediate 60h-1. LC-MS: m / z 711.6 [M + H] ⁺ .

Step I - Synthesis of intermediate 60i-1 To a solution of intermediate 60h-1 (80 mg, 0.113 mmol) in ethanol (5 mL) was added Pd/C (30 mg, 10 wt.%, 50% humidity). The reaction mixture was stirred under H ₂ (1 atm) at ambient temperature for 1 hour and then filtered. The filtrate was concentrated in vacuo to afford intermediate 60i-1. LC-MS: m/z 577.5 [M+H] ⁺ .

Example 89: Preparation of Compound 119

(S)-2-((R)-6-(N-(6-(Aminomethyl)-6-fluorospiro[3.3]hept-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid (single diastereomer, stereochemistry not specified * marks carbon center)

Compound 119 was prepared from intermediate 60i-1 according to the procedures in step B to step D of Example 82. Compound 119: LC-MS: m/z 767.6 [M+H] ⁺ . ¹ H NMR (500 MHz, 400 uL D ₂ O/100 uL CD ₃ CN) δ: 7.42-7.39 (m, 2H), 6.93-6.88 (m, 2H), 4.45-4.42 (m, 1H), 4.12-4.08 (m, 1H), 3.27-3.21 (m, 2H), 2.81 (br s, 2H), 2.65-2.22 (m, 7H), 2.10 (br s, 1H), 1.99-1.97 (m, 2H), 1.78 (br s, 1H), 1.54 (s, 3H), 1.45 (s, 3H), 1.26 (s, 3H).

Example 90: Preparation of Intermediate 61f

Step A - Synthesis of Intermediate 61a To a stirred solution of (1S,3R)-3-((tert-butoxycarbonyl)amino)-2,2-dimethylcyclobutane-1-carboxylic acid methyl ester (510 mg, 1.982 mmol) in THF (15 mL) was added LAH in THF (2M, 1.486 mL, 2.97 mmol) at -12°C (ice/acetone bath). The reaction was stirred at -10°C for 45 minutes, then quenched with NaOH (1 N, 20 mL) and extracted with EtOAc (2×50 mL). The combined organic layers were washed with brine, dried over anhydrous MgSO ₄ , and filtered. The filtrate was concentrated in vacuo to give Intermediate 61a, which was used in the next step without further purification. TLC: 50% EtOAc/hexanes, Rf=0.3.

Step B - Synthesis of Intermediate 61b To a stirred solution of intermediate 61a (456 mg, 1.988 mmol) and TEA (0.416 mL, 2.98 mmol) in THF (15 mL) at 0°C was added methanesulfonyl chloride (0.185 mL, 2.386 mmol). The reaction was allowed to warm to ambient temperature and stirred for 1 hour. The reaction was then quenched with saturated NaHCO ₃ solution and extracted with EtOAc. The organic layer was separated, washed with brine, dried over anhydrous MgSO ₄ , and filtered. The filtrate was concentrated in vacuo to give intermediate 61b, which was used in the next step without further purification. TLC: 50% EtOAc/hexanes, Rf=0.5.

Step C - Synthesis of Intermediate 61c _NaN3 (258 mg, 3.97 mmol) was added to a stirred solution of intermediate 61b (610 mg, 1.984 mmol) in DMF (10 mL) at ambient temperature. The reaction was stirred at 70°C for 3 hours, then quenched with saturated _NaHCO3 solution and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous _MgSO4 and filtered. The filtrate was concentrated in vacuo and the resulting residue was purified by silica gel chromatography (ISCO, 40 g column, gradient elution with 0-70% EtOAc in hexanes) to afford intermediate 61c. TLC: 50% EtOAc/hexanes, Rf=0.8.

Step D - Synthesis of Intermediate 61d To a solution of intermediate 61c (250 mg, 0.983 mmol) in DCM (5 mL) was added TFA (1 mL). The reaction was stirred at ambient temperature for 1 hour. The reaction mixture was then concentrated in vacuo to afford intermediate 61d, which was used in the next step without further purification. TLC: 50% EtOAc/hexanes, Rf=0.

Step E - Synthesis of Intermediate 61e To a vial containing a mixture of intermediate 61d (124 mg, 0.804 mmol) in anhydrous acetonitrile (5 mL) was added intermediate 3c (0.25 g, 0.536 mmol) and acetic acid (0.107 mL, 1.875 mmol). The reaction mixture was heated at 65 °C for 1 hour. The reaction mixture was then cooled to ambient temperature and purified by reverse phase HPLC (ISCO, C18, 50 g column, eluted with 0-100% ACN + 0.05% TFA / water + 0.05% TFA gradient) to give intermediate 61e. LC-MS: m / z 573.5 [M + H] ⁺ .

Step F - Synthesis of Intermediate 61f To a solution of intermediate 61e (170 mg, 0.297 mmol) in ethanol (5 mL) was added Pd/C (50 mg, 10 wt.%, 50% humidity). The reaction mixture was stirred under H ₂ (1 atm) at ambient temperature for 1 hour and then filtered. The filtrate was concentrated in vacuo to afford intermediate 61f, which was used in the next step without further purification. LC-MS: m/z 547.6 [M+H] ⁺ .

Example 91: Preparation of Compound 120

(S)-2-((R)-6-(N-((1R,3S)-3-(aminomethyl)-2,2-dimethylcyclobutyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Compound 120 was prepared from Intermediate 61f according to the procedures in Step B to Step D of Example 82. LC-MS: m/z 737.5 [M+H] ⁺ . ¹ H NMR (500 MHz, 400 uL D ₂ O/100 uL CD ₃ CN) δ: 7.30-7.27 (m, 2H), 6.80-6.77 (m, 2H), 4.56 (s, 1H), 4.38-4.35 (m, 1H), 3.89-3.85 (m, 1H), 3.03-2.98 (m, 1H), 2.87-2.82 (m, 1H), 2.71 (br s, 2H), 2.47-2.41 (m, 1H), 2.02 (br s, 2H), 1.87-1.79 (m, 1H), 1.71 (br s, 1H), 1.45(s, 3H), 1.33(s, 3H), 1.16(s, 3H), 1.12(s, 3H), 0.97(s, 3H).

Example 92: Preparation of Intermediate 62c-1

Step A - Synthesis of intermediate 62a To a solution of tert-butyl ((6-oxospiro [3.3] hept-2-yl) methyl) carbamate (500 mg, 2.089 mmol) in DCM (8 mL) was added benzylamine (0.297 mL, 2.72 mmol). The mixture was stirred at ambient temperature for 10 minutes, and then NaBH (OAc) ₃ (886 mg, 4.18 mmol) and acetic acid (1.196 μL, 0.021 mmol) were added sequentially. The reaction was stirred at ambient temperature for 3 hours, then cooled to 0 ° C and quenched with NaOH (1N). The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous MgSO ₄ and filtered. The filtrate was concentrated in vacuo. The resulting residue was purified by silica gel chromatography (ISCO, 40 g column, gradient elution with 0-100% EtOAc in hexanes) to give intermediate 62a. LC-MS: m/z [M+H] ⁺ .

Step B-Synthesis of Intermediate 62b-1 The enantiomers of intermediate 62a (440 mg, 1.331 mmol) were further separated by AS-H column (21X250 mm, co-solvent, 10% EtOH + 0.2% DIPA, 210 nm wavelength, injection volume 1.0 mL, flow rate 50 mL/min) to give intermediate 62b-1 (first eluting stereoisomer) and intermediate 62b-2 (second eluting stereoisomer). LC-MS: m/z 331.4 [M+H] ⁺ .

Step C - Synthesis of intermediate 62c-1 To a solution of intermediate 62b-1 (110 mg, 0.333 mmol) in EtOH (5 mL) was added Pd/C (30 mg, 10 wt.%, 50% humidity). The mixture was stirred under _H2 (1 atm) at ambient temperature for 40 minutes and then filtered. The filtrate was concentrated in vacuo to give intermediate 62c-1, which was used in the next step without further purification. TLC: EtOAc/hexane 1/1, Rf=0.1.

Example 93: Preparation of Compound 121

(2S)-2-((2R)-6-(N-(6-(Aminomethyl)spiro[3.3]hept-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid*

Compound 121 was prepared from intermediate 62c-1 according to the procedures in step A to step D of Example 82. Compound 121: LC-MS: m/z 749.4 [M+H] ⁺ . ¹ H NMR (500 MHz, 400 uL D ₂ O/100 uL CD ₃ CN) δ: 7.35-7.32 (m, 2H), 6.86-6.83 (m, 2H), 4.58 (s, 1H), 4.41-4.39 (m, 1H), 4.02-3.94 (m, 1H), 2.91-2.89 (m, 2H), 2.76 (br s, 2H), 2.56 (br s, 1H), 2.43-2.38(m, 2H), 2.24-2.04(m, 5H), 1.95-1.92(m, 1H), 1.82-1.71(m, 2H), 1.49(s, 3H), 1.39(s, 3H), 1.20(s, 3H).

*Single diastereomer, not specified* Stereochemistry of the marked carbon center.

Example 94: Preparation of Compounds 122 and 123 (2S)-2-((2R)-6-(N-((1S)-1-aminospiro[2.3]hexan-5-yl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene ((((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)oxy)propanoic acid and (2S)-2-((2R)-6-(N-((1R)-1-aminospiro[2.3]hexan-5-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid*

Step A - Synthesis of Intermediate 63a To a vial containing a mixture of tert-butyl (5-aminospiro [2.3] hexan-1-yl) carbamate (291 mg, 1.372 mmol) in anhydrous acetonitrile (8 mL) was added acetic acid (0.172 mL, 3.00 mmol) followed by Intermediate 3c (400 mg, 0.857 mmol). The reaction mixture was stirred at 65 °C for 4 hours, then cooled to ambient temperature and purified by reverse phase HPLC (ISCO, C18, 150 g column; gradient elution with 0-100% ACN + 0.05% TFA / water + 0.05% TFA) to afford Intermediate 63a as a mixture of diastereomers. LC-MS: m / z 631.4 [M + H] ⁺ .

Step B - Synthesis of Intermediates 63b-1 and 63b-2 The two diastereomers of intermediate 63a (370 mg, 0.587 mmol) were further separated by SFC (AS-H, 250 mm column, co-solvent, 25% MeOH/ACN 1:1 + 0.2% DIPA, 210 nm wavelength, injection volume 1.5 mL, flow rate 50 mL/min) to give intermediate 63b-1 (first eluting stereoisomer) and intermediate 63b-2 (second eluting stereoisomer). LC-MS: m/z 631.4 [M+H] ⁺ .

Step C - Synthesis of Intermediate 63c-2 To a vial containing intermediate 63b-2 (0.21 g, 0.333 mmol) was added 2:1 trifluoroacetic acid/anhydrous DCM (6 mL) at ambient temperature. The reaction was stirred for 16 hours, then a solution of 4:1 toluene/MeOH (10 mL) was added, and the reaction mixture was concentrated in vacuo. The resulting residue was azeotroped with 4:1 toluene/MeOH (10 mL) and dried under high vacuum to give the crude intermediate 63c-2, which was used in the next step without further purification. LC-MS: m/z 375.2 [M+H] ⁺ .

Step D - Synthesis of Intermediate 63d-2 To a vial containing Intermediate 63c-2 (0.125 g, 0.334 mmol) and Intermediate 4 (0.155 g, 0.334 mmol) was added MeOH (5.0 mL) at ambient temperature. The reaction mixture was stirred for 6 hours and then concentrated in vacuo to give the crude Intermediate 63d-2, which was used in the next step without further purification. LC-MS: m/z 822.0 [M+H] ⁺ .

Step E - Synthesis of Compounds 122 and 123 To a vial containing intermediate 63d-2 (0.274 g, 0.334 mmol) was added 1:2 trifluoroacetic acid/anhydrous dichloromethane (6 mL) at ambient temperature. The reaction mixture was stirred for 1 hour and then cooled to 0°C, followed by the slow addition of ether (6 mL) at 0°C. The resulting precipitate was collected by centrifugation (1400 rpm) and further purified by reverse phase HPLC (Gilson; C18, 5um, OBD 30X150 mm column; gradient elution with 0-40% ACN+0.05% TFA/water+0.05% TFA for 18 minutes; 30 mL/min). The product fractions were collected and concentrated in vacuo. The resulting aqueous layer was loaded directly onto an Amberchrom CG161M column (26 g), washed with 9 CV of (water + 0.1% FA), eluted with 3 CV of 100% (MeCN + 0.1% FA), and then 3 CV of 50% (MeCN + 0.1% FA) / (water + 0.1% FA). The product fractions were collected, concentrated in vacuo, and the resulting aqueous residue was freeze-dried to give compound 122 as a formate salt. LC-MS: m/z 721.4 [M+H] ⁺ . ¹ H NMR (500 MHz, 400 uL D ₂ O/100 uL CD ₃ CN) δ: 7.38-7.27 (m, 2H), 6.91 (s, 1H), 6.78 (d, J=15 Hz, 1H), 4.57 (s, 1H), 4.44-4.29 (m, 2H), 2.72 (br s, 2H), 2.60-2.37 (m, 5H), 2.03 (br s, 1H), 1.72 (br s, 1H), 1.49 (s, 3H), 1.32 (s, 3H), 1.05 (s, 3H), 1.04-1.01 (m, 1H), 0.85-0.79 (m, 1H).

Compound 123 was prepared from intermediate 63b-1 according to the procedure of step C to step E of Example 94. LC-MS (ESI): m/z 721.4 [M+H] ⁺ . ¹ HNMR (500 MHz, 400 uL D ₂ O/100 uL CD ₃ CN) δ: 7.49-7.44 (m, 2H), 6.99-6.91 (m, 2H), 4.51-4.48 (m, 1H), 4.40 (br s, 1H), 2.88 (br s, 2H), 2.65 (br s, 4H), 2.16 (br s, 1H), 2.04-2.00 (m, 2H), 1.82 (br s, 1H), 1.52 (s, 3H), 1.49 (s, 3H), 1.31 (s, 3H), 1.12-1.05 (m, 1H), 0.93-0.85 (m, 1H). *Each compound is a single diastereomer; the stereochemistry of the *marked carbon center is not specified.

Example 95: Preparation of Intermediates 64c-1 and 64c-2

Step A - Synthesis of Intermediate 64a To a mixture of Intermediate 1c (500 mg, 1.599 mmol), bis(pinacolato)diboron (507 mg, 1.998 mmol), 2-dicyclohexylphosphine-2',6'-dimethoxy-biphenyl (131 mg, 0.320 mmol), palladium acetate (35.9 mg, 0.160 mmol) and potassium acetate (471 mg, 4.80 mmol) was added THF (14 mL). The reaction flask was filled with _N2 and sealed. The reaction mixture was heated at 70°C for 18 hours, then filtered and the filtrate was concentrated in vacuo. The resulting residue was purified by silica gel column (Redish, 40 g, gradient: 0-100% TBME/hexanes) to give the desired compound. LC-MS: m/z 831.6 [2M+Na] ⁺ .

Step B-Synthesis of Intermediate 64b To a stirred solution of intermediate 64a (606 mg, 1.499 mmol) in 15 mL THF at 0°C was added 2M aqueous sodium hydroxide solution (3.75 mL, 7.49 mmol), followed by 30% aqueous hydrogen peroxide solution (0.759 mL, 7.49 mmol). The reaction was stirred at 0°C for 20 minutes, then quenched by addition of aqueous HCl solution (2N, 2.5 mL). The resulting mixture was diluted with water (100 mL) and extracted with EtOAc (100 mL). The organic layer was separated and concentrated in vacuo. The resulting residue was purified by reverse phase HPLC (150 g C18 column, gradient 0-100% ACN + 0.05% TFA / water + 0.05% TFA) to give intermediate 64b. LC-MS (ESI): m / z LC-MS (ESI): m / z 317.2 [M + Na] ⁺ .

Step C - Synthesis of Intermediates 64c-1 and 64c-2 To a solution of intermediate 64b (400 mg, 1.359 mmol) in acetonitrile (11 mL) were added paraformaldehyde (612 mg, 6.79 mmol), NEt ₃ (2.462 mL, 17.67 mmol) and magnesium chloride (647 mg, 6.79 mmol) in sequence. The reaction was stirred at 85 °C for 5 hours, then HCl (2N, 10 mL) and 30 mL of water were added. The mixture was extracted with EtOAc (30 mL×3). The organic layers were combined, washed with brine (30 mL), dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography (ISCO; 4 g Agela Silica Flash Column, 0-15% EtOAc/petroleum ether gradient @ 30 mL/min) to afford intermediate 64c-1 (first eluting isomer) and intermediate 64c-2 (second eluting isomer).

Intermediate 64c-1: ¹ H NMR (400 MHz, CDCl3) δ: 10.49 (s, 1H), 9.75 (s, 1H), 6.88 (s, 1H), 6.70 (s, 1H), 4.14 (dd, J=2.3, 11.0 Hz, 1H), 3.42 (s, 1H), 2.95-2.84 (m, 2H), 2.12-1.93 (m, 2H), 1.54-1.52 (m, 1H), 1.54 (s, 9H), 1.40 (s, 3H).

Intermediate 64c-2: ¹ H NMR (400 MHz, CDCl3) δ: 11.62 (s, 1H), 10.26 (s, 1H), 6.95 (d, J = 9.0 Hz, 1H), 6.75 (d, J = 9.0 Hz, 1H), 4.12-4.03 (m, 1H), 3.42 (s, 1H), 3.31 (br dd, J = 4.3, 16.8 Hz, 1H), 3.14-2.99 (m, 1H), 2.22-2.11 (m, 1H), 2.09-1.95 (m, 1H), 1.52 (s, 9H), 1.41 (s, 3H).

Example 96: Preparation of Compound 124

(S)-2-((R)-6-(N-((1s,3S)-3-aminocyclobutyl)carbamimidyl)-5-(methoxymethyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 65a To a stirred solution of intermediate 64c-2 (7 g, 21.72 mmol) in DCM (217 mL) was added triethylamine (15.13 mL, 109 mmol) and 1,1,1-trifluoro-N-phenyl-N-((trifluoromethyl)sulfonyl)methanesulfonamide (23.27 g, 65.1 mmol) at 25° C. The reaction was stirred at 25° C. for 14 h and then concentrated under reduced pressure to give the crude product which was purified by flash silica gel chromatography (ISCO; 80 g Agela Silica Flash Column, 0-8% EtOAc/petroleum ether gradient elution @ 30 mL/min) to give intermediate 65a. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 10.40 (s, 1H), 7.12 (d, J=9.0 Hz, 1H), 6.99 (d, J=9.0 Hz, 1H), 4.16 (dd, J=11.3, 2.0 Hz, 1H), 3.43 (s, 1H), 3.41-3.29 (m, 1H), 3.04 (ddd, J=18.6, 12.5, 6.5 Hz, 1H), 2.18-2.08 (m, 1H), 1.97-1.81 (m, 1H), 1.50 (s, 9H), 1.39 (s, 3H).

Step B-Synthesis of Intermediate 65b To a stirred solution of intermediate 65a (3 g, 6.60 mmol) in MeOH (66.0 mL) was added NaBH ₄ (0.749 g, 19.81 mmol) in portions at 0°C. The reaction was stirred at 0°C for 0.5 h, then diluted with water (100 mL) and concentrated to remove most of the MeOH. The resulting mixture was extracted with EtOAc (80 mL×3). The organic layers were combined, washed with brine (100 mL), dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated under reduced pressure to give the crude intermediate 65b, which was used in the next step without further purification. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 6.99 (br d, J=9.0 Hz, 1H), 6.74 (d, J=9.0 Hz, 1H), 4.76-4.61 (m, 2H), 4.15 (br s, 1H), 3.15 (br dd, J=17.1, 4.9 Hz, 1H), 3.00-2.85 (m, 1H), 2.14 (br dd, J=13.6, 4.8 Hz, 1H), 2.01-1.91 (m, 1H), 1.51 (s, 9H), 1.40 (s, 3H).

Step C - Synthesis of Intermediate 65c To a stirred solution of intermediate 65b (2.8 g, 6.13 mmol) in DCM (61.3 mL) at 0°C were added 2,6-di-tert-butylpyridine (12.32 g, 64.4 mmol), silver trifluoromethanesulfonate (14.19 g, 55.2 mmol) and iodomethane (4.01 mL, 64.4 mmol) in sequence. The reaction was stirred at 20°C for 72 hours and then filtered. The filtrate was diluted with _H2O (80 mL) and extracted with DCM (60 mL x 3). The organic layers were combined, washed with brine, dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 40 g Agela Silica Flash Column, 0-20% EtOAc/petroleum ether gradient elution @ 30 mL/min) to afford intermediate 65c. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.00 (d, J=9.4 Hz, 1H), 6.74 (d, J=9.4 Hz, 1H), 4.57-4.39 (m, 2H), 4.12 (br d, J=11.0 Hz, 1H), 3.39 (s, 3H), 3.10-2.99 (m, 1H), 2.97-2.79 (m, 1H), 2.12 (br dd, J=13.5, 6.1 Hz, 1H), 1.96 (dq, J=12.5, 5.5 Hz, 1H), 1.50 (s, 9H), 1.39 (s, 3H).

Step D - Synthesis of Intermediate 65d To a mixture of intermediate 65c (800 mg, 1.700 mmol) and sodium carbonate (21.63 mg, 0.204 mmol) in MeCN (8 mL) and H ₂ O (6 mL) under N ₂ was added potassium ferrocyanide trihydrate (359 mg, 0.850 mmol) and chloro(2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl)[2-(2'-amino-1,1'-biphenyl)]palladium(II). The reaction was stirred at 100 °C under microwave irradiation for 40 min, then filtered, the filtrate was diluted with H ₂ O (40 mL), and extracted with EtOAc (30 mL×3). The organic layers were combined, washed with brine, dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 4 g Agela Silica Flash Column, 0-15% EtOAc/petroleum ether gradient elution @ 30 mL/min) to afford Intermediate 65d. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.38 (d, J=8.6 Hz, 1H), 6.76 (d, J=8.6 Hz, 1H), 4.62 (q, J=11.2 Hz, 2H), 4.18 (dd, J=11.0, 2.0 Hz, 1H), 3.42 (s, 3H), 3.10-2.99 (m, 1H), 2.92-2.77 (m, 1H), 2.14 (br dd, J=13.7, 6.3 Hz, 1H), 2.03-1.92 (m, 1H), 1.50 (s, 9H), 1.40 (s, 3H).

Step E - Synthesis of Intermediate 65e To a stirred solution of intermediate 65d (710 mg, 2.044 mmol) in THF (21 mL) was added sodium hydride (245 mg, 6.13 mmol, 60% in mineral oil) at 0°C under _N2 . The mixture was stirred at 0°C for 20 minutes before the addition of O-diphenylphosphino-hydroxylamine (858 mg, 3.68 mmol). The reaction was then stirred at 0°C for 1.5 hours and at 20°C for 3 hours. The reaction mixture was quenched with saturated aqueous _NH4Cl solution (20 mL) and extracted with EtOAc (50 mL x 3). The organic layers were combined, dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 12 g AgelaSilica Flash Column, 0-15% petroleum ether/EtOAc gradient elution @ 30 mL/min) to afford intermediate 65e. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.38 (d, J=8.6 Hz, 1H), 6.85 (d, J=8.6 Hz, 1H), 5.47 (br s, 2H), 4.66-4.55 (m, 2H), 4.24 (br d, J=11.3 Hz, 1H), 3.41 (s, 3H), 3.04-2.96 (m, 1H), 2.90-2.77 (m, 1H), 2.21-2.09 (m, 1H), 1.85 (dq, J=12.8, 5.1 Hz, 1H), 1.51 (s, 12H).

Step F - Synthesis of Intermediate 65f To a stirred solution of intermediate 65e (520 mg, 1.435 mmol) in DCE (14 mL) was added _Boc2O (1.155 mL, 5.02 mmol) at 20°C. The reaction was stirred at 55°C for 16 hours. The reaction mixture was then concentrated under reduced pressure and the resulting residue was purified by flash silica gel chromatography (ISCO; 4 g Agela Silica Flash Column, 0-18% petroleum ether/EtOAc gradient elution @ 30 mL/min) to afford intermediate 65f. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.53 (s, 1H), 7.37 (d, J=8.6 Hz, 1H), 6.80 (d, J=8.6 Hz, 1H), 4.71-4.54 (m, 2H), 4.29 (dd, J=11.0, 2.3 Hz, 1H), 3.41 (s, 3H), 3.05 (br dd, J=17.2, 3.1 Hz, 1H), 2.88-2.76 (m, 1H), 2.27-2.07 (m, 2H), 1.55 (s, 3H), 1.50 (s, 9H), 1.45 (s, 9H).

Step G - Synthesis of Intermediate 65g To a solution of a mixture of Intermediate 65f (520 mg, 1.124 mmol) and TEA (0.548 mL, 3.93 mmol) in pyridine (6 mL) was added (NH ₄ ) ₂ S (5.75 mL, 16.86 mmol, 20% aqueous solution). The mixture was stirred at 60° C. for 18 hours, then cooled and concentrated in vacuo to remove residual solvent. The residue was washed with brine (20 mL) and extracted with ethyl acetate (30 mL×3). The organic layer was dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo. The residue was purified by flash silica gel chromatography (ISCO; 4 g Agela Silica Flash Column, 0-35% EtOAc/petroleum ether gradient elution @ 30 mL/min) to give Intermediate 65g. LC-MS (ESI): m/z 496.9 [M+H] ⁺ .

Step H - Synthesis of Intermediate 65h To a solution of intermediate 65g (350 mg, 0.705 mmol) in MeCN (7 mL) was added iodomethane (0.219 mL, 3.52 mmol) dropwise and the reaction was stirred at 25°C for 16 hours. The reaction mixture was then concentrated under vacuum to give the crude intermediate 65h, which was used in the next step without purification. LC-MS (ESI): m/z 511.4 [M+H] ⁺ .

Step I - Synthesis of intermediate 65i To a solution of intermediate 65h (300 mg, 0.587 mmol) in MeCN (3 mL) stirred at 20°C was added a solution of (tert-butyl((1s,3s)-3-aminocyclobutyl)carbamate (207 mg, 1.111 mmol) and AcOH (0.3 mL, 5.24 mmol) in MeCN (3 mL). The reaction was stirred at 85°C for 5 hours, then filtered and the filtrate concentrated under reduced pressure. The resulting residue was purified by reverse phase MPLC (Biotage; 20 g Agela, C18, 20-35 μm, 20% MeCN/H ₂ O (0.5% TFA) gradient elution @ 50 mL/min) to afford intermediate 65i. LC-MS (ESI): m/z 649.4 [M+H] ⁺ .

Step J - Synthesis of Intermediate 65j A solution of intermediate 65i (400 mg, 0.462 mmol) in TFA (6 mL) was stirred at 40°C for 2 hours. The solvent was removed under vacuum and the residue was purified by reverse phase HPLC (column: Boston Uni C18 40×150×5 um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1) to give intermediate 65j. LC-MS (ESI): m/z 392.8 [M+H] ⁺ .

Step K - Synthesis of Compound 124 A mixture of molecular sieves (50 mg), intermediate 65j (130 mg, 0.331 mmol) and intermediate 5 (121 mg, 0.331 mmol) in DMA (2.5 mL) was stirred at 28 °C for 16 hours. The reaction mixture was then filtered. The filtrate was diluted with MeOH (2 mL) and purified by reverse phase HPLC (column: Boston Uni C18 40×150×5 um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 1) to give the product as a TFA salt. The TFA salt was dissolved in 2:1 H ₂ O/MeCN (2 mL) and purified by reverse phase HPLC (column: Welch Xtimate C18 150×25 mm×5 um; conditions: water (0.225% FA)-ACN; start B0, end B19; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 2). The product fractions were collected and concentrated in vacuo, and the resulting aqueous residue was freeze-dried to give compound 124 as a formate salt. LC-MS (ESI): m/z 739.4 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.17 (d, J=8.6 Hz, 1H), 6.90-6.79 (m, 2H), 4.66 (s, 1H), 4.42 (br s, 2H), 4.29 (br d, J = 10.2 Hz, 1H), 4.10-3.95 (m, 1H), 3.67-3.52 (m, 1H), 3.25 (s, 3H), 2.96-2.79 (m, 3H), 2.77-2.63 (m, 1H), 2.33-2.19 (m, 2H), 2.13-2.01 (m, 1H), 1.81-1.60 (m, 1H), 1.49 (s, 3H), 1.43 (s, 3H), 1.24 (s, 3H).

Example 97: Preparation of Compound 125

(S)-2-((R)-6-(N-((1s,3S)-3-aminocyclobutyl)carbamimidyl)-7-(methoxymethyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Compound 125 was prepared from intermediate 64c-1 according to the procedures in step A to step K of Example 96. LC-MS (ESI): m/z 739.3 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.23 (s, 1H), 6.83 (s, 1H), 6.79 (s, 1H), 4.65 (s, 1H), 4.41 (s, 2H), 4.34 (br d, J = 10.2 Hz, 1H), 3.99 (quin, J = 7.9 Hz, 1H), 3.60 (quin, J = 8.3 Hz, 1H), 3.22 (s, 3H), 2.93-2.82 (m, 2H), 2.81-2.68 (m, 2H), 2.33-2.21 (m, 2H), 2.08-1.98 (m, 1H), 1.78-1.62 (m, 1H), 1.48 (s, 3H), 1.43 (s, 3H), 1.25 (s, 3H).

Example 98: Preparation of Compounds 126 and 127

(S)-2-((R)-6-(N-((1s,4S)-4-amino-1-(methoxymethyl)cyclohexyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1r,4R)-4-amino-1-(methoxymethyl)cyclohexyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 66a A solution of TEA (8.84 mL, 63.4 mmol), diphenylphosphoryl azide (7.31 mL, 33.9 mmol) and 8-(methoxymethyl)-1,4-azaspiro[4.5]decane-8-carboxylic acid (7.3 g, 31.7 mmol) in toluene (30 mL) and THF (30 mL) was stirred at 65 °C for 3 hours. The reaction mixture was then cooled to ambient temperature, diluted with EtOAc (50 mL), washed with brine (200 mL), dried over _{anhydrous Na2SO4} , and filtered. The filtrate was concentrated in vacuo. The resulting residue was dissolved in THF (50 mL) and toluene (50 mL), and 2-(trimethylsilyl)ethanol (7.28 g, 61.6 mmol) was added. The reaction was stirred at 95 °C for 16 hours, then cooled to ambient temperature and concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (Biotage; 40 g Agela Silica Flash Column, 0-13% EtOAc/petroleum ether gradient elution @ 45 mL/min) to afford Intermediate 66a. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 4.49 (s, 1H), 4.12-3.98 (m, 2H), 3.95-3.83 (m, 4H), 3.52-3.39 (m, 2H), 3.36-3.17 (m, 3H), 2.15-2.01 (m, 2H), 1.81-1.48 (m, 6H), 1.04-0.85 (m, 2H), -0.01 (s, 9H).

Step B - Synthesis of Intermediate 66b A solution of intermediate 66a (6.9 g, 19.97 mmol) and p-toluenesulfonic acid (27.5 g, 160 mmol) in 1:1 THF/water (100 mL) was stirred at 19°C for 16 hours. The reaction mixture was then diluted with EtOAc (80 mL), washed with brine (80 mL), dried over _{anhydrous Na2SO4} , filtered and the filtrate concentrated in vacuo. The resulting residue was purified by silica gel column chromatography eluting with 3:1 petroleum ether/EtOAc to afford intermediate 66b. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 4.71 (s, 1H), 4.18-4.06 (m, 2H), 3.49 (s, 2H), 3.36 (s, 3H), 2.56-2.37 (m, 4H), 2.33-2.24 (m, 2H), 1.87-1.74 (m, 2H), 1.02-0.92 (m, 2H), 0.03 (s, 9H).

Step C-Synthesis of Intermediate 66c To a stirred solution of intermediate 66b (4.0 g, 13.27 mmol) in THF (40 mL) was added dibenzylamine (3.06 mL, 15.92 mmol) at 0 ° C. After stirring at 25 ° C for 2 hours, the reaction was cooled to 0 ° C and acetic acid (0.836 mL, 14.60 mmol) was added, followed by sodium triacetoxyborohydride (7.03 g, 33.2 mmol). The reaction was stirred at 25 ° C for 12 hours, then the pH of the reaction mixture was adjusted to pH 6-7 with saturated NaHCO ₃ aqueous solution (50 mL), and the mixture was extracted with EtOAc (50 mL×3). The combined organic layers were washed with brine (50 mL) and concentrated in vacuo. The residue was purified by flash silica gel chromatography MPLC ( 40g The residue was purified by silica flash column, 0-10% ethyl acetate/petroleum ether gradient elution @ 40 mL/min) to afford intermediate 66c. LC-MS (ESI): m/z 483.8 [M+H] ⁺ .

Step D - Synthesis of intermediate 66d To a mixed solvent solution of intermediate 66c (3.5 g, 7.25 mmol) in MeOH (10 mL) and EtOAc (50 mL) under _N2 atmosphere were added palladium hydroxide (20%, 5.09 g, 7.25 mmol), Pd/C (7.72 g, 7.25 mmol, 10 wt.%) and ammonium hydroxide solution (25 wt%, 1.016 g, 7.25 mmol). The suspension was degassed under vacuum and purged with _H2 three times. The reaction mixture was stirred at 30 °C under _H2 (30 psi) for 12 h and then filtered. The filtrate was concentrated in vacuo to give the crude intermediate 66d, which was used in the next step without further purification. LC-MS (ESI): m/z 303.0 [M+H] ⁺ .

Step E - Synthesis of Intermediates 66e-1 and 66e-2 To a stirred mixture of intermediate 66d (1.5 g, 4.96 mmol) and K ₂ CO ₃ (1.713 g, 12.40 mmol) in MeOH (30 mL) was added CbzCl (0.991 mL, 6.94 mmol) at 0°C. The reaction mixture was stirred at 20°C for 12 hours, then diluted with water (40 mL) and extracted with EtOAc (30 mL×3). The combined organic layers were washed with brine (80 mL), dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (Biotage; 12 g Agela Silica Flash Column, 0-25% EtOAc/petroleum ether gradient elution @ 40 mL/min) to give a mixture of cis- and trans-stereoisomers. The mixture of stereoisomers was further separated by SFC (DAICEL CHIRALPAK AD (250 mm×50 mm, 10 um); condition 0.1% NH ₃ ·H ₂ O/EtOH; start B 25%, end B 25%; flow rate (mL/min) 200; injection 120) to give intermediate 66e-1 (first eluting stereoisomer, LC-MS (ESI): m/z 437.4 [M+H] ⁺ ) and intermediate 66e-2 (second eluting stereoisomer, LC-MS (ESI): m/z 437.4 [M+H] ⁺ ), respectively.

Step F - Synthesis of intermediate 66f-2 To a solution of intermediate 66e-2 (900 mg, 2.061 mmol) in DCM (10 mL) was added TFA (1 mL). The reaction was stirred at 20 °C for 2 hours and then concentrated in vacuo to give the crude intermediate 66f-2, which was used in the next step without further purification. LC-MS (ESI): m/z 293.1 [M+H] ⁺ .

Step G-Synthesis of Intermediate 66g-2 To a solution of crude intermediate 66f-2 (233 mg, 0.573 mmol) in DMF (3 mL) was added a solution of TEA (0.240 mL, 1.720 mmol) at 0 ° C, followed by dropwise addition of a solution of intermediate 6c (270 mg, 0.573 mmol) in DMF (3 mL). The reaction was stirred at 20 ° C for 12 hours, then diluted with water (40 mL) and extracted with ethyl acetate (30 mL×2). The combined organic layers were washed with brine (40 mL), dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo to give the crude intermediate 66g-2, which was used for the next step without further purification. LC-MS (ESI): m/z 727.4 [M+H] ⁺ .

Step H - Synthesis of intermediate 66h-2 To a stirred mixture of K ₂ CO ₃ (665 mg, 4.82 mmol) in MeOH (5 mL) at 20 °C under N ₂ was added formic acid (443 mg, 9.63 mmol). The mixture was stirred for 10 min and then diluted with MeOH (10 mL). The resulting solution was added to a solution of intermediate 66g-2 (700 mg, 0.963 mmol) and acetic anhydride (108 mg, 1.059 mmol) in acetic acid (12.79 mL) which had been pre-stirred at ambient temperature for 5 min. Pd/C (10 wt.%, 41.0 mg, 0.385 mmol) was then added and the reaction mixture was stirred at 20 °C for 12 h. The reaction mixture was filtered and the solvent was removed under vacuum. The resulting residue was purified by reverse phase MPLC (Biotage; 20 g Agela, 0-38% MeCN/H ₂ O (0.5% TFA) gradient elution @ 50 mL/min) to afford intermediate 66h-2. LC-MS (ESI): m/z 577.4 [M+H] ⁺ .

Step I - Synthesis of Intermediate 66i-2 A solution of intermediate 66h-2 (240 mg, 0.416 mmol) in TFA (5 mL) was stirred at 40 °C for 1 hour, and then the reaction mixture was concentrated in vacuo. The resulting residue was purified by reverse phase HPLC (Boston Uni C18 40×150×5 um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 2) to give intermediate 66i-2. LC-MS (ESI): m/z 421.2 [M+H]+.

Step J - Synthesis of Compounds 126 and 127 To a stirred solution of intermediate 66i-2 (115 mg, 0.273 mmol) in DMA (3 mL) at 20°C was added intermediate 5 (100 mg, 0.273 mmol). The reaction mixture was stirred at 20°C for 12 hours and then dried with a stream of nitrogen. The resulting residue was purified by reverse phase HPLC (Boston Uni C18 40×150×5 um; conditions: water (0.1% TFA)-ACN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 2) to give the product as a TFA salt. The TFA salt was dissolved in H ₂ O (3 mL) and purified by HPLC (Welch Xtimate C18 150×25 mm×5 um; conditions: water (0.225% FA)-ACN; start B 0, end B19; elution time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 2), and then freeze-dried to give compound 126 as formate salt. LC-MS (ESI): m/z 767.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.52-7.39 (m, 2H), 6.90 (br d, J＝9.3 Hz, 1H), 6.79 (s, 1H), 4.62 (s, 1H), 4.39 (br d, J = 11.1 Hz, 1H), 3.51 (s, 2H), 3.37 (s, 3H), 3.26-3.14 (m, 1H), 2.89-2.76 (m, 2H), 2.43-2.29 (m, 2H), 2.15-2.05 (m, 2H), 1.81-1.66 (m, 1H), 1.64-1.46 (m, 5H), 1.51 (s, 3H), 1.43 (s, 3H), 1.25 (s, 3H).

Compound 127 was prepared from intermediate 66e-1 according to the procedures in step F to step J of the Example. LC-MS (ESI): m/z 767.4 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.40-7.33 (m, 2H), 6.88 (d, J=8.6 Hz, 1H), 6.78 (s, 1H), 4.61 (s, 1H), 4.39 (br d, J = 10.2 Hz, 1H), 3.67 (s, 2H), 3.41 (s, 3H), 3.32-3.21 (m, 1H), 2.86-2.73 (m, 2H), 2.24-2.15 (m, 2H), 2.13-2.02 (m, 1H), 2.01-1.95 (m, 2H), 1.78-1.65 (m, 3H), 1.61-1.45 (m, 5H), 1.43 (s, 3H), 1.25 (s, 3H).

Example 99: Preparation of Compounds 128 and 129

(S)-2-((R)-6-(N-((1s,4S)-4-amino-4-(methoxymethyl)cyclohexyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(methoxymethyl)cyclohexyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 67a Pd/C (11.21 mg, 10 wt.%, 0.105 mmol) was added to a solution of intermediate 66e-2 in methanol (10 mL). The mixture was stirred at 25 °C under _H2 atmosphere (15 psi) for 1.5 hours. The reaction mixture was then filtered through Celite ^TM and the filtrate was concentrated under reduced pressure to give intermediate 67a, which was used in the next step without further purification. LC-MS (ESI): m/z 303.2 [M+H] ⁺ .

Step B - Synthesis of Intermediate 67b To a stirred solution of Intermediate 3c (470 mg, 1.007 mmol) and Intermediate 67a (305 mg, 1.007 mmol) in MeCN (9 mL) at 22°C was added acetic acid (0.231 mL, 4.03 mmol) and potassium acetate (297 mg, 3.02 mmol) in sequence. The reaction was stirred at 80°C for 30 min, then diluted with water (30 mL) and extracted with EtOAc (50 mL x 3). The organic layers were combined, dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by reverse phase MPLC (Biotage; 40 g Agela, C18, 20-35 μm, 0-40% MeCN/ _H2O (0.5% TFA) gradient elution @ 50 mL/min) to afford Intermediate 67b. LC-MS (ESI): m/z 721.4 [M+H] ⁺ .

Step C - Synthesis of Intermediate 67c A solution of intermediate 67b (460 mg, 0.638 mmol) in TFA (6 mL) was stirred at 40°C for 1 hour. The reaction mixture was then concentrated in vacuo to afford intermediate 67c, which was used in the next step without further purification. LC-MS (ESI): m/z 421.1 [M+H] ⁺ .

Step D - Synthesis of Compound 128 To a solution of intermediate 67c (268 mg, 0.637 mmol) in MeOH (5 mL) was added intermediate 5 (232 mg, 0.637 mmol). The reaction was stirred at 26°C for 16 hours, then diluted with MeOH (3 mL) and purified by reverse phase HPLC (column: Boston Uni C18 40×150×5 um; conditions: water (0.1% TFA)-CAN; start B 0, end B 30; gradient time (min) 11; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 2) to give the product as a TFA salt. The TFA salt was further purified by reverse phase HPLC (column: Welch Xtimate C18 150×25 mm×5 um; conditions: water (0.225% FA)-CAN; start B 0, end B19; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 2) and then freeze-dried to give compound 128 as a formate salt. LC-MS (ESI): m/z 767.3 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ ) δ 7.42 (br s, 2H), 6.91 (br d, J=9.0 Hz, 1H), 6.75 (s, 1H), 4.62 (s, 1H), 4.41 (br d, J=11.3 Hz, 1H), 3.74-3.63 (m, 1H), 3.38-3.29 (m, 2H), 3.30 (s, 3H), 2.80-2.65 (m, 2H), 1.99-1.55 (m, 9H), 1.40 (s, 3H), 1.39 (s, 3H), 1.27-1.18 (m, 4H).

Compound 129 was prepared according to the procedures in step A to step D of Example 99 by replacing intermediate 66e-2 with intermediate 66e-1. LC-MS (ESI): m/z 767.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O) δ: 7.45-7.28 (m, 2H), 6.87 (d, J=8.6 Hz, 1H), 6.82 (s, 1H), 4.59 (s, 1H), 4.40 (br d, J=11.3 Hz, 1H), 3.58 (s, 3H), 3.34 (s, 3H), 2.87-2.68 (m, 2H), 2.10-1.96 (m, 5H), 1.78-1.52 (m, 5H), 1.50 (s, 3H), 1.41 (s, 3H), 1.23 (s, 3H).

Example 100: Preparation of Intermediates 68d-1 and 68d-2

Step A - Synthesis of Intermediate 68a To a _stirred solution of tert-butyl (1-methyl-4-oxocyclohexyl) carbamate (2 g, 8.80 mmol) and 1-((isocyanomethyl)sulfonyl)-4-methylbenzene (1.890 g, 9.68 mmol) in DME (20 mL) was added potassium 2-methylpropan-2-olate (1 M t-BuOH solution) (15.84 mL, 15.84 mmol) dropwise at -20 °C under N2. The reaction was warmed to 20 °C and stirred for 12 hours, then diluted with saturated aqueous _NH4Cl solution (60 mL) and extracted with EtOAc (90 mL x 3). The organic layers were combined, washed with brine (60 mL), dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column eluting with petroleum ether/EtOAc: 20:1 to 10:1 gradient to afford Intermediate 68a. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 4.27 (br s, 1H), 2.77 (br t, J=4.7 Hz, 0.5H), 2.50-2.39 (m, 0.5H), 2.17-2.08 (m, 1H), 2.05-1.96 (m, 1H), 1.93-1.73 (m, 4H), 1.71-1.55 (m, 2H), 1.63-1.43 (m, 9H), 1.33-1.31 (m, 3H).

Step B - Synthesis of Intermediate 68b To a solution of intermediate 68a (2.9 g, 12.17 mmol) in THF (25 mL) was added LiAlH ₄ (0.748 g, 19.71 mmol) at 0°C. The reaction was stirred at 25°C for 2.5 hours and then quenched with 1 M NaOH (20 mL) and H ₂ O (10 mL) at 0°C. The resulting mixture was extracted with ethyl acetate (3×150 mL). The combined organic layers were dried over anhydrous MgSO ₄ , filtered, and the filtrate was concentrated in vacuo to afford intermediate 68b, which was used in the next step without further purification. LC-MS (ESI): m/z 243.2 [M+H] ⁺ .

Step C - Synthesis of Intermediates 68c-1 and 68c-2 To a solution of intermediate 68b (1.4 g, 5.78 mmol) in THF (16 mL) and water (8 mL) was added Na ₂ CO ₃ (1.837 g, 17.33 mmol) and benzyl chloroformate (1.024 mL, 7.51 mmol), and the reaction mixture was stirred at 0°C for 12 hours, then diluted with water (50 mL) and extracted with ethyl acetate (130 mL×3). The combined organic layers were washed with brine (60 mL), dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo and the resulting residue was purified by silica gel column eluting with a gradient of petroleum ether:EtOAc 8:1-5:1 to give the product as a mixture of cis- and trans-isomers. The cis/trans mixture was further purified by SFC (column: DAICEL CHIRALCEL OJ (250 mm*50 mm, 10 um); condition: 0.1% NH ₃ ·H ₂ O/EtOH; start B 30%, end: B 30%; flow rate (mL/min): 200; injection: 300) to give intermediate 68c-1 (first eluting isomer) and intermediate 68c-2 (second eluting isomer), respectively.

Intermediate 68c-1: ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.42-7.28 (m, 5H), 5.13-5.06 (m, 2H), 4.82 (br s, 1H), 4.26 (br s, 1H), 3.07 (br t, J=6.5 Hz, 2H), 2.09 (br d, J=12.1 Hz, 2H), 1.65 (br d, J=11.0 Hz, 1H), 1.56 (br d, J=13.7 Hz, 2H), 1.43 (s, 9H), 1.29 (s, 3H), 1.21-1.06 (m, 4H).

Intermediate 68c-2: ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.40-7.29 (m, 5H), 5.09 (s, 2H), 4.77 (br s, 1H), 4.44 (br s, 1H), 3.09 (br t, J=6.5 Hz, 2H), 1.83 (br d, J=12.5 Hz, 2H), 1.63 (br t, J=11.9 Hz, 5H), 1.43 (s, 9H), 1.29 (s, 3H), 1.19-1.07 (m, 2H).

Step D - Synthesis of Intermediates 68d-1 and 68d-2 A solution of intermediate 68c-1 (300 mg, 0.797 mmol) in 1,4-dioxane (5 mL, 4 M) was stirred at 20°C for 2 hours. The reaction mixture was then concentrated in vacuo to afford intermediate 68d-1, which was used in the next step without further purification. LC-MS (ESI): m/z 277.1 [M+H] ⁺ .

Intermediate 68d-2 was prepared from intermediate 68c-2 according to the procedure in step D of example 100. ¹ H NMR (400 MHz, CD ₃ OD) δ: 7.40-7.26 (m, 5H), 5.07 (s, 2H), 3.02 (d, J=6.6 Hz, 2H), 1.86-1.70 (m, 4H), 1.69-1.42 (m, 3H), 1.34 (s, 3H), 1.20 (q, J=12.0 Hz, 2H).

Example 101: Preparation of Compounds 130 and 131

(S)-2-((R)-6-(N-((1s,4S)-4-(aminomethyl)-1-methylcyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1r,4R)-4-(aminomethyl)-1-methylcyclohexyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Compounds 130 and 131 were prepared from intermediate 68d-1 and intermediate 68d-2 according to the procedures in step A to step E of example 48.

Compound 130: LC-MS (ESI): m/z 751.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.39-7.30 (m, 2H), 6.88 (d, J=9.6 Hz, 1H), 6.80 (s, 1H), 4.62 (s, 1H), 4.38 (br d, J=11.4 Hz, 1H), 2.89-2.73 (m, 4H), 2.25 (br d, J=14.2 Hz, 2H), 2.08 (br d, J = 14.7 Hz, 1H), 1.80-1.63 (m, 4H), 1.50 (s, 3H), 1.55-1.45 (m, 2H), 1.50 (s, 3H), 1.38 (s, 3H), 1.25 (s, 3H), 1.20-1.07 (m, 2H).

Compound 131: LC-MS (ESI): m/z 751.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.40-7.30 (m, 2H), 6.87 (d, J=8.5 Hz, 1H), 6.79 (s, 1H), 4.62 (s, 1H), 4.37 (br d, J=10.3 Hz, 1H), 2.90-2.70 (m, 4H), 2.12-1.98 (m, 3H), 1.80-1.60 (m, 6H), 1.49 (s, 3H), 1.42 (s, 6H), 1.30-1.14 (m, 2H), 1.24 (s, 3H).

Example 102: Preparation of Intermediates 69e-1 and 69e-2

Step A-Synthesis of Intermediate 69a To a stirred solution of 4-(dibenzylamino)cyclohexane-1-carboxylic acid (8.4 g, 26.0 mmol) in THF (88 mL) at 0°C was added di-tert-butyl dicarbonate (7.76 mL, 33.8 mmol) and ammonium bicarbonate (5.34 g, 67.5 mmol). Pyridine (2.06 mL, 26.0 mmol) was then added and the reaction was stirred at room temperature for 12 hours. The reaction mixture was then poured into a saturated aqueous sodium bicarbonate solution (50 mL) and extracted with ethyl acetate (50 mL×3). The combined organic layers were washed with brine (30 mL), dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo to give Intermediate 69a. It was used in the next step without further purification. LC-MS (ESI): m/z 323.3[M+H] ⁺ .

Step B - Synthesis of Intermediate 69b To a stirred solution of intermediate 69a (8.37 g, 26.0 mmol) and triethylamine (14.43 mL, 104 mmol) in dry THF (179 mL) was added trifluoroacetic anhydride (5.77 mL, 41.5 mmol) at 0°C. The reaction was stirred at 0-10°C under nitrogen atmosphere for 2 hours, then quenched with ice-cold water and extracted with ethyl acetate (3 x 60 mL). The combined organic layers were washed with brine (50 mL), dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated in vacuo. The residue was purified by flash silica gel chromatography MPLC ( 120g The resulting residue was purified by Silica Flash Column, 0-12.4% ethyl acetate/petroleum ether gradient elution @ 60 mL/min) to afford Intermediate 69b as a mixture of cis/trans stereoisomers. LC-MS (ESI): m/z 305.2 [M+H] ⁺ .

Step C - Synthesis of Intermediate 69c Cerium (III) chloride (18.31 g, 74.3 mmol) was dried at 140°C under vacuum stirring for 2 hours, then THF (130 mL) was added. The resulting suspension was cooled to -65°C, followed by the dropwise addition of 1.6 N methyllithium in _Et2O solution (47.6 mL, 76 mmol). The reaction mixture was stirred at -65°C for 1 hour. A solution of intermediate 69b (5.8 g, 19.05 mmol) in THF (10 mL) was then added dropwise at -65°C. The reaction mixture was warmed to room temperature and stirred for 16 hours. The reaction mixture was then filtered, and the filtrate was concentrated in vacuo. The resulting residue was partitioned between saturated _NH4Cl aqueous solution (100 mL) and _CH2Cl2 ( ₂₀ mL). The aqueous layer was separated _and extracted with _CH2Cl2 (50 mL x 3). The combined organic layers were washed with brine (50 mL), dried over anhydrous Na ₂ SO ₄ and concentrated in vacuo to afford Intermediate 69c, which was used in the next reaction without further purification. LC-MS (ESI): m/z 337.0 [M+H] ⁺ .

Step D - Synthesis of Intermediates 69d-1 and 69d-2 To a stirred solution of intermediate 69c (6.41 g, 19.05 mmol) and TEA (9.29 mL, 66.7 mmol) in DCM (121 mL) at 15° C. was added (Boc) ₂ O (7.96 mL, 34.3 mmol). The reaction was stirred at 15° C. for 16 hours and then concentrated in vacuo. The residue was purified by flash silica gel chromatography MPLC ( 80g The resulting residue was directly purified by Silica Flash Column, 0-15% ethyl acetate/petroleum ether gradient elution @ 45 mL/min). The product fractions were combined and concentrated under vacuum. Petroleum ether was added to the resulting residue and the mixture was filtered. The insoluble solid was collected to give intermediate 69d-2 (LC-MS (ESI): m/z 437.5 [M+H] ⁺ ). The filtrate was concentrated in vacuo to give intermediate 69d-1 (LC-MS (ESI): m/z 437.5 [M+H] ⁺ ).

Step E - Synthesis of Intermediates 69e-1 and 69e-2 To a mixture of MeOH (3 mL) and EtOAc (15 mL) of intermediate 69d-1 (850 mg, 1.947 _mmol ) was added 20% palladium hydroxide (200 mg, 0.285 mmol), Pd/C (200 mg, 10 wt.%, 0.188 mmol) and aqueous ammonium hydroxide (85 mg, 0.603 mmol) under N2 atmosphere. The suspension was degassed under vacuum and purged with _H2 three times. The reaction mixture was stirred at 20 °C under _H2 (15 psi) for 2 h and then filtered. The filtrate was concentrated in vacuo to give intermediate 69e-1, which was used in the next step without further purification. ¹ H NMR (500 MHz, CD ₃ OD) δ: 3.10 (br s, 1H), 1.83 (br t, J=11.9 Hz, 1H), 1.74 (br d, J=13.4 Hz, 2H), 1.63-1.50 (m, 4H), 1.46-1.32 (m, 11H), 1.22 (s, 6H).

Intermediate 69e-2 was prepared according to the procedure for the synthesis of Intermediate 69d-2. ¹ H NMR (400 MHz, CD ₃ OD) δ: 2.95 (br t, J=11.7 Hz, 1H), 2.07 (br d, J=10.8 Hz, 2H), 1.96 (br s, 1H), 1.84 (br d, J=12.2 Hz, 2H), 1.42 (s, 11H), 1.34 (br d, J=13.9 Hz, 2H), 1.20 (s, 6H).

Example 103: Preparation of Compounds 132 and 133 (S)-2-((R)-6-(N-((1s,4S)-4-(2-aminopropan-2-yl)cyclohexyl)carbamimidyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylene ((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)oxy)propanoic acid and (S)-2-((R)-6-(N-((1r,4R)-4-(2-aminopropan-2-yl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

According to the procedures in step I to step K of Example 96, compounds 132 and 133 were prepared from the corresponding intermediate 69e-1 and intermediate 69e-2.

Compound 132: LC-MS (ESI): m/z 765.4 [M+H] ⁺ . ¹ H NMR (400 MHz, CD ₃ CN+D ₂ O) δ: 7.40-7.31 (m, 2H), 6.89 (d, J=8.6 Hz, 1H), 6.79 (s, 1H), 4.63 (s, 1H), 4.38 (br d, J=11.3 Hz, 1H), 3.91 (br s, 1H), 2.84-2.77 (m, 2H), 2.15-2.03 (m, 3H), 1.76-1.54 (m, 6H), 1.50 (s, 3H), 1.43 (s, 3H), 1.38-1.30 (m, 2H), 1.29 (s, 3H), 1.26 (s, 6H).

Compound 133: LC-MS (ESI): m/z 765.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN+formicacid)δ:7.76-7.62(m,2H),7.34(s,1H),7.19(d,J＝8.6Hz,1H),5.19-5.04(m,1H),4.75-4.57(m,1H),3.90-3.78(m,1H),3.19-3.10(m,2H),2.53-2.40(m,3H),2.32-2.25(m,3H),2.15-2.03(m,3H),1.89-1.77(m,1H),1.75-1.65(m,5H),1.62-1.48(m,8H),1.47(s,3H).

Example 104: Preparation of Intermediate 70c

Step A - Synthesis of Intermediate 70a To a stirred solution of intermediate 64c-1 (480 mg, 1.489 mmol) in EtOH (20 mL) was added palladium on carbon (317 mg, 10 wt.%, 0.298 mmol) in one portion at 28°C. The reaction was stirred under _H2 (50 psi) at 28°C for 18 hours and then filtered. The filtrate was concentrated under reduced pressure to give intermediate 70a, which was used in the next step without further purification. ¹ H NMR (400 MHz, CD ₃ OD) δ: 6.41 (d, J=10.3 Hz, 2H), 4.03 (dd, J=1.7, 11.2 Hz, 1H), 2.85-2.73 (m, 1H), 2.71-2.63 (m, 1H), 2.08 (s, 3H), 2.01 (br dd, J=6.2, 13.3 Hz, 1H), 1.84 (dt, J=5.6, 12.2 Hz, 1H), 1.51 (s, 9H), 1.35 (s, 3H).

Step B - Synthesis of Intermediate 70b TEA (0.870 mL, 6.24 mmol) and 1,1,1-trifluoro-N-phenyl-N-((trifluoromethyl)sulfonyl)methanesulfonamide (1.27 g, 3.56 mmol) were added sequentially to a stirred solution of intermediate 70a (0.550 g, 1.784 mmol) in DCM (15 mL) at 15°C. The reaction was stirred at 15°C for 16 hours and then concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 20 g Agela Silica Flash Column, 0-15% EtOAc/petroleum ether gradient elution @ 30 mL/min) to afford intermediate 70b. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 6.92 (s, 1H), 6.62 (s, 1H), 4.18-4.12 (m, 1H), 3.40 (s, 1H), 2.92-2.77 (m, 2H), 2.27 (s, 3H), 2.12-2.06 (m, 1H), 2.02-1.89 (m, 1H), 1.53 (s, 9H), 1.39 (s, 3H).

Step C - Synthesis of Intermediate 70c To a mixture of intermediate 70b (730 mg, 1.657 mmol), sodium carbonate (26.4 mg, 0.249 mmol) in MeCN (6 mL) and H ₂ O (5 mL) under N ₂ was added potassium ferrocyanide trihydrate (350 mg, 0.829 mmol) and chloro(2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl)[2-(2'-amino-1,1'-biphenyl)]palladium(II) (261 mg, 0.331 mmol). The reaction was stirred at 100 °C for 50 min under microwave irradiation. The reaction mixture was then filtered, and the filtrate was diluted with H ₂ O (40 mL) and extracted with EtOAc (20 mL×3). The organic layers were combined, washed with brine, dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated under reduced pressure and the residue was purified by flash silica gel chromatography (ISCO; 12 g Agela Silica Flash Column, 0-15% EtOAc/petroleum ether gradient elution @ 30 mL/min) to afford Intermediate 70c. ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.29 (s, 1H), 6.61 (s, 1H), 4.19 (dd, J=2.3, 11.0 Hz, 1H), 3.40 (s, 1H), 2.87-2.76 (m, 2H), 2.42 (s, 3H), 2.14-2.05 (m, 1H), 2.01-1.89 (m, 1H), 1.52 (s, 9H), 1.39 (s, 3H).

Example 105: Preparation of Compound 134

(S)-2-((R)-6-(N-((1s,3S)-3-aminocyclobutyl)carbamimidyl)-7-methylchroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Compound 134 was prepared from Intermediate 70c according to the procedure in Step E to Step K of Example 96. LC-MS (ESI): m/z 709.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.08 (s, 1H), 6.80 (s, 1H), 6.68 (s, 1H), 4.66 (s, 1H), 4.30 (br d, J = 11.3 Hz, 1H), 4.05-3.95 (m, 1H), 3.64-3.54 (m, 1H), 2.93-2.82 (m, 2H), 2.81-2.63 (m, 2H), 2.34-2.24 (m, 2H), 2.22 (s, 3H), 2.09-2.00 (m, 1H), 1.75-1.60 (m, 1H), 1.48 (s, 3H), 1.44 (s, 3H), 1.26 (s, 3H).

Example 106: Preparation of Compound 135

(S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(hydroxymethyl)-1-methylcyclohexyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 71a To a solution of benzyl (8-methyl-1,4-dioxaspiro [4.5] -dec-8-yl) carbamate (5.6 g, 18.34 mmol) in DMF (180 mL) stirred at 0 ° C was added NaH (1.467 g, 60 wt.%, 36.7 mmol) in portions. The reaction was stirred for 20 minutes, and then BnBr (3.92 mL, 33.0 mmol) was added dropwise at 0 ° C. The reaction mixture was stirred at 30 ° C for 2.5 hours, and then diluted with saturated NH ₄ Cl aqueous solution (200 mL) and extracted with EtOAc (50 mL×5). The combined organic layers were washed with brine (50 mL), dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo and the resulting residue was purified by flash silica chromatography (ISCO; 40 g Agela Silica Flash Column, 0-25% EtOAc/petroleum ether gradient elution @ 40 mL/min) to afford Intermediate 71a. LC-MS (ESI): m/z 396.2 [M+H] ⁺ .

Step B - Synthesis of Intermediate 71b To a stirred solution of intermediate 71a (11.238 g, 28.4 mmol) in THF (140 mL) and water (140 mL) was added 4-methylbenzenesulfonic acid hydrate (10.81 g, 56.8 mmol) at 15°C. The reaction mixture was stirred at 30°C for 72 hours, then diluted with saturated aqueous _NaHCO3 (280 mL) and extracted with EtOAc (80 mL x 3). The organic layers were combined, washed with brine (100 mL), dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography (ISCO; 80 g Agela Silica Flash Column, 0-28% EtOAc/petroleum ether gradient elution @ 60 mL/min) to afford intermediate 71b. LC-MS (ESI): m/z 352.1 [M+H] ⁺ .

Step C - Synthesis of Intermediate 71c To a stirred solution of intermediate 71b (7.738 g, 22.02 mmol) and chloroform (7.5 mL, 93 mmol) in THF (114 mL) was added LiHMDS (1 M THF solution, 48.4 mL, 48.4 mmol) dropwise at -78°C. The reaction was stirred at -78°C for 1 hour and then poured into a saturated aqueous NH ₄ Cl solution (300 mL) and extracted with EtOAc (100 mL×3). The organic layers were combined, washed with brine (50 mL), dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (ISCO; 120 g Agela Silica Flash Column, 0-25% EtOAc/petroleum ether gradient elution @ 70 mL/min) to afford intermediate 71c. LC-MS (ESI): m/z 470.0 and 472.0 [M+H] ⁺ .

Step D - Synthesis of Intermediate 71d To a solution of intermediate 71c (5.06 g, 10.75 mmol) in MeOH (237 mL) was added NaN ₃ (2.13 g, 32.8 mmol) and 18-crown-6 (0.568 g, 2.149 mmol). DBU (8.10 mL, 53.7 mmol) was then slowly added and the reaction was stirred at 28° C. for 12 hours. The reaction mixture was then diluted with MTBE (500 mL) and washed with saturated aqueous NH ₄ Cl solution (450 mL). The organic layer was separated, dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo. The resulting residue was purified by flash silica gel chromatography (ISCO; 40 g Agela Silica Flash Column, 0-12% EtOAc/petroleum ether gradient elution @ 40 mL/min) to afford intermediate 71d. LC-MS (ESI): m/z 459.1 [M+Na] ⁺ .

Step E-Synthesis of intermediate 71e To a solution of intermediate 71d (4.4 g, 10.08 mmol) in THF (44 mL) and AcOH (44 mL) was added zinc powder (3.30 g, 50.4 mmol) in one portion. The reaction mixture was stirred at 28 ° C for 1.5 hours and then filtered. The filter cake was rinsed with EtOAc (200 mL). The filtrate was concentrated in vacuo to remove most of the solvent. The resulting residue was dissolved in EtOAc (300 mL) and washed with saturated NaHCO ₃ aqueous solution (50 mL) and brine (50 mL). The organic layer was dried over anhydrous Na ₂ SO ₄ and filtered. The filtrate was concentrated in vacuo to give intermediate 71e, which was used in the next step reaction without further purification. LC-MS (ESI): m/z 411.2 [M+H] ⁺ .

Step F - Synthesis of Intermediate 71f To a stirred solution of di-tert-butyl dicarbonate (5.75 g, 26.4 mmol) and triethylamine (3.20 g, 31.6 mmol) in EtOH (43 mL) at 65°C was added dropwise a solution of Intermediate 71e (4.328 g, 10.54 mmol) in DMF (13 mL). The reaction was stirred at 65°C for 1 hour, then cooled to room temperature, diluted with water (150 mL), and extracted with EtOAc (40 mL x 4). The organic layers were combined, washed with brine (30 mL), dried over _{anhydrous Na2SO4} , and filtered. The filtrate was concentrated in vacuo and the resulting residue was purified by flash silica gel chromatography (ISCO; 80 g Agela Silica Flash Column, 0-40% EtOAc/petroleum ether gradient elution @ 60 mL/min) to afford Intermediate 71f. LC-MS (ESI): m/z 511.2 [M+Na] ⁺ . ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.35-7.14 (m, 10H), 5.12 (s, 2H), 4.77 (s, 1H), 4.65 (s, 2H), 3.66 (s, 3H), 2.47 (br d, J=14.1 Hz, 2H), 2.08-1.96 (m, 2H), 1.82 (br d, J=13.7 Hz, 2H), 1.69-1.57 (m, 2H), 1.42 (s, 9H), 1.25 (s, 3H).

Step G - Synthesis of Intermediate 71g A solution of Intermediate 71f (3.556 g, 6.96 mmol) in THF (36 mL) was slowly added dropwise to a stirred mixture of LiBH ₄ (1.517 g, 69.6 mmol) in THF (36 mL) at 0°C. The cooling bath was then removed and the reaction was stirred at 28°C for 12 hours. The reaction was then cooled in an ice bath and quenched by dropwise addition of aqueous hydrochloric acid (1 M, 30 mL). The resulting mixture was extracted with EtOAc (25 mL×3). The organic layers were combined, dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo and the resulting residue was purified by flash silica gel chromatography (ISCO; 20 g Agela Silica Flash Column, 0-100% EtOAc/petroleum ether gradient elution @ 35 mL/min) to afford Intermediate 71g. LC-MS (ESI): m/z 505.2 [M+Na] ⁺ .

Step H - Synthesis of Intermediate 71h To a stirred solution of Intermediate 71g (1.74 g, 3.61 mmol) and TBS-Cl (0.652 g, 4.33 mmol) in DCM (26 mL) was added imidazole (0.368 g, 5.41 mmol). The reaction was stirred at 28°C for 12 hours, then diluted with DCM (100 mL), washed with brine (30 mL), dried over _Na2SO4 , and filtered. The filtrate was concentrated in vacuo and the resulting residue was purified by flash _silica gel chromatography (ISCO; 20 g Agela Silica Flash Column, 0-30% EtOAc/petroleum ether gradient elution @ 35 mL/min) to afford Intermediate 71h. LC-MS (ESI): m/z 597.3 [M+H] ⁺ .

Step I - Synthesis of Intermediate 71i A mixture of intermediate 71h (1500 mg, 2.51 mmol), acetic acid (0.719 mL, 12.57 mmol) and Pd/C (600 mg, 10 wt.%, 0.564 mmol) in MeOH (40 mL) was stirred at 20°C under hydrogen atmosphere (15 psi) for 12 hours. The reaction mixture was then filtered and the filtrate was concentrated in vacuo to afford intermediate 71i, which was used in the next step without further purification. ¹ H NMR (400 MHz, CD ₃ OD) δ: 3.70 (s, 2H), 2.15-2.05 (m, 2H), 1.83-1.47 (m, 6H), 1.43 (s, 9H), 1.36 (s, 3H), 0.92 (s, 9H), 0.07 (s, 6H).

Step J-Synthesis of Intermediate 71j To a solution of intermediate 71i (689 mg, 1.849 mmol) in DMF (5.2 mL) stirred at 0°C was added TEA (0.991 mL, 7.11 mmol). Then a solution of intermediate 6c (670 mg, 1.423 mmol) in DMF (2.1 mL) was added dropwise. The reaction was stirred at 28°C for 1 hour, then diluted with water (30 mL) and extracted with ethyl acetate (10 mL×4). The combined organic layers were washed with brine (5 mL), dried over anhydrous Na ₂ SO ₄ , and filtered. The filtrate was concentrated in vacuo to give intermediate 71j, which was used in the next step without further purification. LC-MS (ESI): m/z 807.5[M+H] ⁺ .

Step K - Synthesis of Intermediate _71k To a mixture of _K2CO3 (0.983 g, 7.11 mmol) in MeOH (15 mL) was added formic acid (0.655 g, 14.22 mmol). The reaction was stirred under _N2 for 10 min and then added to a solution of Intermediate 71j (1.148 g, 1.422 mmol) in acetic acid (9 mL) and acetic anhydride (0.160 g, 1.565 mmol) pre-stirred at ambient temperature for 5 min. Pd/C (0.605 g, 10 wt.%, 0.569 mmol) was then added and the reaction was stirred at 28°C for 12 h. The reaction mixture was then filtered and the filtrate was concentrated in vacuo. The resulting residue was dissolved in EtOAc (100 mL), washed sequentially with saturated aqueous _NaHCO3 (25 mL) and brine (15 mL), dried over _{anhydrous Na2SO4} and filtered. The filtrate was concentrated in vacuo and the residue was purified by MPLC (Biotage; 20 g Agela, C18, 20-35 μm, 0-45% MeCN/H ₂ O (0.5% TFA) gradient elution @ 50 mL/min) to afford Intermediate 71k. LC-MS (ESI): m/z 791.5 [M+H] ⁺ .

Step L - Synthesis of Intermediate 711 A mixture of Intermediate 71k (325 mg, 0.411 mmol) and TFA (3.2 mL, 41.5 mmol) was stirred at 40° C. for 70 minutes. The reaction mixture was then concentrated under vacuum to afford Intermediate 711, which was used in the next step without further purification. LC-MS (ESI): m/z 420.8 [M+H] ⁺ .

Step M - Synthesis of Compound 135 To a solution of intermediate 711 (173 mg, 0.411 mmol) in MeOH (4.4 mL) was added intermediate 5 (150 mg, 0.411 mmol). The reaction was stirred at ambient temperature for 12 hours, filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was dissolved in MeOH (4 mL) and purified by reverse phase HPLC (column: Boston Uni C18 40×150×5 um; conditions: water (0.1% TFA)-CAN; start B 0, end B 30; gradient time (min) 10; 100% B retention time (min) 2; flow rate (mL/min) 60; injection 2) to give the product as a TFA salt. The TFA salt was purified by another reverse phase HPLC (column: Welch Xtimate C18 150×25 mm×5 um; conditions: water (0.225% FA)-CAN; start B 0, end B18; gradient time (min) 15; 100% B retention time (min) 2; flow rate (mL/min) 25; injection 3). The product fractions were combined and freeze-dried to give compound 135 as a formate salt. LC-MS (ESI): m/z 767.2 [M+H] ⁺ . ¹ H NMR (400 MHz, D ₂ O+CD ₃ CN) δ: 7.38-7.29 (m, 2H), 6.89-6.79 (m, 2H), 4.63 (s, 1H), 4.38 (br d, J=10.2 Hz, 1H), 3.59 (s, 2H), 2.88-2.71 (br s, 2H), 2.13-2.01 (m, 3H), 1.88-1.63 (m, 7H), 1.50 (s, 3H), 1.45 (s, 3H), 1.42 (s, 3H), 1.23 (s, 3H).

Example 107: Preparation of Compound 136

(S)-2-((R)-6-(N-((1R,3r,5S)-8-azabicyclo[3.2.1]octan-3-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Compound 136 was prepared according to the procedure of Example 11 starting from intermediate 3c and commercially available N-Boc-endo-3-aminotropane to afford the title compound as a formate salt. LC-MS: m/z 735.5 [M+H] ⁺ . ¹ HNMR (400 MHz, 4:1 D ₂ O/DMSO-d ₆ )δ:7.36(s,1H),7.33(d,J＝10.4Hz,1H),6.85(d,J＝8.7Hz,1H),6.81(s,1H),4.59(s,1H),4.34(d,J＝10.7Hz,1H),4.03–4.15(m,3H),2.68–2.85(m,2H),2.18(d,J＝16.4Hz,2H),1.98–2.11(m,5H),1.88(t,J＝12.3Hz,2H),1.60-1.75(m,1H),1.46(s,3H),1.38(s,3H),1.20(s,3H).

Example 108: Preparation of Compound 137

(S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3S,5S)-5-(hydroxymethyl)pyrrolidin-3-yl)carbamimidoyl)chroman-2-yl)propanoic acid

Step A - Synthesis of Intermediate 72a To a vial containing a mixture of (2S,4S)-1-boc-2-hydroxymethyl-4-aminopyrrolidine-HCl (130 mg, 0.514 mmol) in anhydrous acetonitrile (6 mL) was added acetic acid (0.086 mL, 1.500 mmol), followed by Intermediate 3c (200 mg, 0.429 mmol) and N,N-diisopropylethylamine (0.224 mL, 1.286 mmol). The reaction mixture was heated at 65 °C for 1 hour, then cooled to ambient temperature and purified by reverse phase Isco Combiflash (150 g, 0-100% 0.05% TFA in ACN/0.05% water) to give Intermediate 72a. LC-MS: m/z 635.4 [M+H] ⁺ .

Step B - Synthesis of Intermediate 72b To a vial containing intermediate 72a (0.068 g, 0.107 mmol) was added 2:1 trifluoroacetic acid/anhydrous dichloromethane (6 mL) at ambient temperature. The reaction was stirred for 16 hours, then a solution of 4:1 toluene/MeOH (5 mL) was added, and the reaction mixture was concentrated in vacuo. The resulting residue was azeotroped with 4:1 toluene/MeOH (5 mL) and then dried under high vacuum to give the crude intermediate 72b, which was used in the next step without further purification. LC-MS: m/z 379.3 [M+H] ⁺ .

Step C - Synthesis of Intermediate 72c To a vial containing Intermediate 72b (0.04 g, 0.108 mmol) and Intermediate 4 (0.05 g, 0.108 mmol) was added MeOH (4.0 mL) at ambient temperature. The reaction mixture was stirred for 6 hours and then concentrated in vacuo to afford Intermediate 72c, which was used in the next step without further purification. LC-MS: m/z 825.6 [M+H] ⁺ .

Step D-Synthesis of Compound 137 At ambient temperature, 1:2 trifluoroacetic acid/anhydrous dichloromethane (6 mL) was added to a vial containing intermediate 72c (0.089 g, 0.108 mmol). The reaction mixture was stirred for 1 hour, then cooled to 0 ° C, and ether (6 mL) was slowly added under stirring. The resulting solid was collected by centrifugation (1400 rpm) and purified by reverse phase HPLC (Gilson, C18, 5 um, OBD 30x150 mm, 0.05% TFA in ACN/0.05% TFA aqueous solution 0-40% gradient elution 18 min; 30 ml/min; injection 3). The product fractions were collected and concentrated in vacuo. The aqueous layer was loaded directly onto an Amberchrom CG161M column (26 g), washed with 9 CV of (water + 0.1% FA), eluted with 3 CV of 100% (AcCN + 0.1% FA), and then 3 CV of 50% (AcCN + 0.1% FA) / (water + 0.1% FA). The product fractions were collected and concentrated in vacuo, and the resulting aqueous residue was freeze-dried to give compound 137 as a formate salt. LC-MS: m/z 725.5 [M+H] ⁺ . ¹ HNMR (500 MHz, 400 uLD ₂ O/100 uL CD ₃ CN) δ: 7.34-7.28 (m, 2H), 6.89 (s, 1H), 6.80-6.79 (d, J=5 Hz, 1H), 4.57-4.49 (m, 1H), 4.42-4.39 (m, 1H), 3.91-3.79 (m, 2H), 3.70-3.62 (m, 2H), 3.45-3.40 (m, 1H), 2.77-2.71 (br s, 2H), 2.66-2.60(m, 1H), 2.06-1.93(m, 3H), 1.78-1.66(m, 1H), 1.47(s, 3H), 1.34(s, 3H), 1.10(s, 3H).

Example 109: Preparation of Intermediate 73b

Step A - Synthesis of Intermediate 73a To a vial containing a mixture of tert-butyl (1-(2-aminoethyl) cyclopropyl) carbamate hydrochloride (150 mg, 0.634 mmol) in DCM (5 mL) solution was added triethylamine (0.442 mL, 3.17 mmol) followed by dropwise addition of benzyl chloroformate (0.625 mL, 0.950 mmol). The reaction mixture was stirred at ambient temperature for 2 hours, then diluted with DCM and washed with saturated aqueous NaHCO ₃ solution. The organic layer was dried over anhydrous MgSO ₄ , filtered, and the filtrate was concentrated in vacuo to afford Intermediate 73a which was used in the next step without further purification. TLC: Rf = 0.5 EtOAc/hexane (1/1), KMnO ₄ staining.

Step B - Synthesis of Intermediate 73b To a stirred solution of intermediate 73a (230 mg, 0.688 mmol) in DCM (5 mL) was added TFA (0.527 mL, 6.88 mmol) at 0°C. The reaction was stirred at ambient temperature for 1 hour and then diluted with 30% toluene/MeOH. The resulting mixture was concentrated in vacuo to afford intermediate 73b which was used in the next step without further purification. TLC: Rf = 0.0, EtOAc/hexane (1/1), KMnO ₄ staining.

Example 110: Preparation of Intermediate 74b

Step A - Synthesis of Intermediate 74a To a vial containing a mixture of tert-butyl (1-(3-aminopropyl)cyclopropyl)carbamate (200 mg, 0.933 mmol) in DCM (5 mL) was added triethylamine (0.65 mL, 4.67 mmol) followed by dropwise addition of benzyl chloroformate (0.92 mL, 1.40 mmol). The reaction mixture was stirred at ambient temperature for 4 hours, then diluted with DCM and washed with saturated aqueous NaHCO ₃ solution. The organic layer was dried over anhydrous MgSO ₄ , filtered, and the filtrate was concentrated in vacuo to afford Intermediate 74a which was used in the next step without further purification. TLC: Rf = 0.5, EtOAc/hexane (1/1), KMnO ₄ staining.

Step B - Synthesis of Intermediate 74b To a stirred solution of intermediate 74a (300 mg, 0.861 mmol) in DCM (5 mL) at 0°C was added TFA (0.66 mL, 8.61 mmol). The reaction was stirred at ambient temperature for 1 hour and then diluted with 30% toluene/MeOH. The resulting mixture was concentrated under vacuum to afford intermediate 74b which was used in the next step without further purification. TLC: Rf = 0.0, EtOAc/hexane (1/1), KMnO ₄ staining.

Example 111: Preparation of Intermediate 75c

Step A - Synthesis of Intermediate 75a To a stirred solution of tert-butyl (1-(2-hydroxy-ethyl)cyclobutyl)carbamate (500 mg, 2.322 mmol) and triethylamine (0.483 mL, 3.48 mmol) in THF (10 mL) at 0°C was added methanesulfonyl chloride (0.216 mL, 2.79 mmol). The reaction was warmed to ambient temperature and stirred for 1 hour, then quenched with saturated aqueous _NaHCO3 and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous _MgSO4 and filtered. The filtrate was concentrated in vacuo to afford Intermediate 75a, which was used in the next reaction without further purification. TLC: Rf = 0.6 EtOAc/hexane (1/1), _KMnO4 staining.

Step B - Synthesis of Intermediate 75b Sodium azide (241 mg, 3.71 mmol) was added to a stirred solution of intermediate 75a (680 mg, 2.318 mmol) in DMF (10 mL). The resulting mixture was heated to 70 ° C and stirred at this temperature for 18 hours. The reaction was then quenched with saturated NaHCO ₃ aqueous solution and extracted with EtOAc. The combined organic layers were washed with brine (2×), dried over anhydrous MgSO ₄ , and filtered. The filtrate was concentrated in vacuo to give intermediate 75b, which was used in the next step without further purification. TLC: Rf = 0.7 EtOAc / hexane (1/1), KMnO ₄ staining.

Step C - Synthesis of Intermediate 75c A mixture of intermediate 75b (200 mg, 0.832 mmol) in DCM (5 mL) / TFA (1.00 mL) was stirred at ambient temperature for 1 hour. The solvent was then removed under vacuum to give intermediate 75b, which was used in the next step without further purification. TLC: Rf = 0.0 EtOAc / hexane (1/1), KMnO ₄ staining.

Example 112: Preparation of Compound 138

(S)-2-((R)-6-(N-(1-(2-aminoethyl)cyclopropyl)amidino)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfonyloxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid

Step A - Synthesis of Intermediate 76a To a stirred solution of Intermediate 73b (149 mg, 0.637 mmol) and Intermediate 6c (200 mg, 0.425 mmol) in anhydrous DMF (3 mL) was added triethylamine (0.592 mL, 4.25 mmol) at ambient temperature. The reaction mixture was stirred for 1 hour and then directly purified by reverse phase MPLC (ISCO; C18, 50 g column; 0-100% 0.05% TFA + water / 0.05% TFA + ACN gradient). The product fractions were combined and concentrated in vacuo. The resulting aqueous mixture was extracted with EtOAc (2×). The combined organic layers were washed with brine, dried over anhydrous Na ₂ SO ₄ , filtered, and the filtrate was concentrated in vacuo to afford Intermediate 76a. LC-MS [M+1]: m/z 669.0.

Step B - Synthesis of Intermediate 76b To a solution of a mixture of potassium carbonate (238 mg, 1.720 mmol) in MeOH (2 mL) was added formic acid (0.132 mL, 3.44 mmol). The mixture was stirred for 10 minutes and then added to a solution of intermediate 76a (230 mg, 0.344 mmol) in AcOH (1.5 mL)/acetic anhydride (0.049 mL, 0.516 mmol). Subsequently, palladium on carbon (146 mg, 10 wt.%, 50% moisture, 0.138 mmol) was added. The reaction mixture was stirred at ambient temperature for 18 hours and then filtered. The filtrate was directly purified by reverse phase (ISCO; C18, 50 g column; 0-100% 0.05% TFA+ACN/0.05% TFA+water; gradient). The product fractions were combined and concentrated in vacuo. The resulting aqueous mixture was extracted with EtOAc (2×). The organic layer was washed with brine, dried over _{anhydrous Na2SO4} , filtered, and the filtrate was concentrated in vacuo to afford Intermediate 76b. LC-MS [M+1]: m/z 519.5.

Step C - Synthesis of intermediate 76c To a vial containing a mixture of intermediate 76b (140 mg, 0.270 mmol) in _CH2Cl2 ( ₂ mL) was added TFA (4 mL). The reaction was stirred at ambient temperature for 18 hours and then concentrated in vacuo. To the resulting residue was added 30% toluene/MeOH (2 x 6 mL) and the mixture was concentrated in vacuo to afford intermediate 76c which was used in the next step without further purification. LC-MS [M+1]: m/z 363.3.

Step D - Synthesis of Intermediate 76d To a vial containing Intermediate 76c (86 mg, 0.237 mmol) and Intermediate 4 (110 mg, 0.237 mmol) was added MeOH (4.0 mL) at ambient temperature. The reaction mixture was stirred for 6 hours, and then the solvent was removed in vacuo to give Intermediate 76d, which was used in the next step without further purification. LC-MS [M+1]: m/z 809.6.

Step E - Synthesis of Compound 138 At ambient temperature, 1:2 trifluoroacetic acid/anhydrous dichloromethane (6 mL) was added to a vial containing intermediate 76d (191 mg, 0.236 mmol). The reaction was stirred at ambient temperature for 1 hour, then cooled to 0°C, followed by the slow addition of ether (6 mL). The resulting solid was collected by centrifugation (1400 rpm) and purified by reverse phase HPLC (Gilson, preparative C18, 5 um, OBD 30x150 mm column; 0.05% TFA+ACN/0.05%/TFA+water 0-40% gradient 18 min, 30 mL/min, injection 3). The product fractions were combined and concentrated in vacuo, and the resulting aqueous solution was directly loaded onto an Amberchrom CG161M column (26 g), washed with 9CV of (water + 0.1% FA), eluted with 3CV of 100% (AcCN + 0.1% FA), and then 3CV of 50% (AcCN + 0.1% FA) / (water + 0.1% FA). The product fractions were combined and concentrated in vacuo, and the resulting aqueous residue was freeze-dried to afford compound 138 as a formate salt. LC-MS [M+1]: m/z 709.6. ¹ H NMR (500 MHz, 400 uL D ₂ O/100 uL CD ₃ CN) δ: 7.46-7.43 (m, 2H), 6.96-6.95 (m, 2H), 4.57-4.49 (m, 1H), 4.53-4.51 (m, 1H), 3.24-3.21 (m, 2H), 2.92-2.85 (m, 2H), 2.19-2.06 (m, 3H), 1.90-1.82 (m, 1H), 1.61 (s, 3H), 1.50 (s, 3H), 1.27 (s, 3H), 1.15 (s, 2H), 1.05 (s, 2H).

Example 113: Preparation of Compounds 139 and 140

According to the procedures in step A to step E of example 112, compounds 139 and 140 were prepared from the corresponding intermediates 74b and 75c.

Bioassay

Antibiotic activity: determination of growth inhibitory concentration

The concentration of compounds required to inhibit the growth of various bacterial strains was determined in an assay that evaluates bacterial growth by measuring the optical density at 600 nm (OD600). The bacteria tested included clinical strains of Escherichia coli (CLB30016) expressing NDM-1, Klebsiella pneumoniae (CL6569) expressing KPC-1, Acinetobacter baumannii (CL6188) expressing TEM-1, AmpC and Oxa-24/40, and Pseudomonas aeruginosa (CL5701) expressing AmpC. All compounds were tested in 384-well microplates in the presence of a β-lactamase inhibitor (BLi, relebactam).

Clinical strains were stored as frozen single-use stocks, thawed and diluted into 1.1× cation-adjusted Mueller-Hinton II broth to achieve approximately 2×10 ⁵ CFU/mL. Test compounds were dissolved in DMSO and diluted 1:50 in the assay, with final concentrations ranging from 100 μM to 0.098 μM. On the day of the assay, 1 μL of the test compound was added to the plate, followed by 4 μL of 50 μg/mL BLi in MOPS buffer and 45 μL of the diluted bacteria. The plates were centrifuged at 1000 rpm for 30 seconds, shaken at approximately 800 rpm for 1 minute, and incubated at 35±2°C for 22 hours. The BLi concentration used in the assay was 4 μg/mL. At the end of the incubation, the absorbance at 600 nm was measured using a spectrophotometer. Inhibition was quantified by determining the minimum test compound concentration required to inhibit 95% bacterial growth. The results of Examples 1-39 are shown in Table 1, expressed as the concentration of compound that inhibits 95% of bacterial growth (minimum inhibitory threshold concentration; MITC95).

Representative compounds of the invention exhibited growth inhibition. For example, representative compounds 1-140 were determined to inhibit growth at concentrations of 100 μM or less.

Table I. Antibacterial activity of compounds 1-140

Claims (31)

1. Compounds of formula I

Or a pharmaceutically acceptable salt thereof, wherein:

t is CH or N, provided that no more than two of T, U and V are N;

u is CH or N;

V is CH or N;

x is selected from the group consisting of

1) O, and

2)CH2；

Y is selected from the group consisting of:

1)O，

2)NR⁸，

3) S, sum of

4)CH₂，

Provided that when Y is O, NR ⁸ or S, X is not O;

Z is

1)O，

2)S，

3) CH ₂, or

4)NH，

Provided that when Z is O, S or NH, X is not O;

W is selected from the group consisting of:

1) A bond, and

2)O；

Q is selected from the group consisting of:

1) N, and

2)CR⁸；

R ¹ is selected from the group consisting of:

1) -a C _3-12 cycloalkyl group,

2) -A C _3-12 cycloalkenyl group, the reaction of which,

3) -A C _2-11 cycloheteroalkyl group,

4) C _2-11 cycloheteroalkenyl groups,

5) Aryl, and

6) A heteroaryl group, which is a group,

Wherein alkyl, cycloalkyl, cycloalkenyl, cycloheteroalkyl, cycloheteroalkenyl, aryl, and heteroaryl are unsubstituted or substituted with one to five substituents selected from R ^a;

r ² is selected from the group consisting of:

The hydrogen is used to produce a hydrogen gas,

1) A C _1-6 -alkyl group, a group containing a hydroxyl group,

2) -C _1-6 alkyl-OR ⁴

3) -C _1-6 alkyl-NHR ⁴,

Wherein alkyl is unsubstituted or substituted with one to three halogens;

r ³ is selected from the group consisting of:

1) Hydrogen, and

2)OH；

R ⁴ is selected from the group consisting of:

1) The hydrogen is used to produce a hydrogen gas,

2) C _1-3 alkyl, and

3) C ₃ cycloalkyl group, which is a group,

Wherein alkyl and cycloalkyl are unsubstituted or substituted with one to three halogen or OC _1-3 alkyl groups;

r ⁵ is selected from the group consisting of:

1) -CO ₂ H, and

2) Tetrazole;

R ⁶ and R ⁷ are selected from the group consisting of:

1) Hydrogen, and

2) A C _1-6 -alkyl group, a group,

Wherein alkyl is unsubstituted or substituted with one to three halo, provided that at least one of R ⁶ and R ⁷ is hydrogen;

R ⁸ is independently selected from the group consisting of:

1) The hydrogen is used to produce a hydrogen gas,

2) A C _1-4 -alkyl group, a group,

3) Halogen, and

4) C _3-7 cycloalkyl group, which is a group,

Wherein alkyl and cycloalkyl are unsubstituted or substituted with one to three substituents selected from the group consisting of: -OH, halogen, NH ₂ and-OC _1-3 alkyl;

R ⁹ and R ¹⁰ are selected from the group consisting of:

1) Hydrogen, and

2) A C _1-6 -alkyl group, a group,

Wherein alkyl is unsubstituted or substituted with one to three substituents selected from the group consisting of: halogen, OH, -OC _1-3 alkyl, -NHC (O) C _1-3 alkyl, -C (O) NHC _1-3 alkyl, NHC _1-3 alkyl and SC _1-3 alkyl, provided that one or both of R ⁹ and R ¹⁰ are C _1-6 alkyl,

Or R ⁹ and R ¹⁰ together with the carbon to which they are attached form a monocyclic C _3-5 cycloalkyl or a monocyclic C _2-5 cycloheteroalkyl, wherein cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with one to three substituents independently selected from halogen, -OH and-OC _1-3 alkyl;

Each R ^a is independently selected from the group consisting of:

A halogen atom,

1) A C _1-6 -alkyl group, a group containing a hydroxyl group,

2) -C _0-6 alkyl-O-C _1-6 alkyl,

3) -A C _0-6 alkyl-OH group,

4) C _0-6 alkyl S (O) _rR^j,

5) C _0-6 alkyl S (O) _rNR^kR^l,

6) C _0-6 AlkylC (O) R ⁱ,

7) C _0-6 alkyl OC (O) R ⁱ,

8) C _0-6 AlkylC (O) OR ⁱ,

9) -A C _0-6 alkyl group CN,

10 C _0-6 alkyl C (O) NR ^kR^l,

11 -C _0-6 alkyl C (NH) NR ^kR^l,

12 A) C _0-6 alkyl NR ^kR^l,

13 C _0-6 alkyl N (R ^k)(C(O)Rⁱ),

14C _0-6 alkyl N (R ^k)(C(O)OR^h),

15 -C _0-6 alkyl N (R ^k)(C(O)NR^fR^g), and

16 C _0-6 alkyl N (R ^k)(S(O)_vR^j),

Wherein alkyl is unsubstituted or substituted with one to three substituents selected from the group consisting of: halogen, OH, -OC _1-3 alkyl, -C _1-3 alkyl, -CO ₂C_1-3 alkyl, -C (O) NH ₂、-C_0-6 alkyl NH ₂ and-C _0-6 alkyl NH (C _1-3 alkyl);

Each R ^b is independently selected from the group consisting of:

1) The hydrogen is used to produce a hydrogen gas,

2) A C _1-6 -alkyl group, a group containing a hydroxyl group,

3) -C _0-6 alkyl-O-C _1-6 alkyl,

4) -A C _0-6 alkyl-OH group,

5) C _0-6 alkyl-S (O) _uR^d,

6) C _1-6 alkyl-C (O-N (R ^e)₂,

7) C _1-6 alkyl N (R ^e)C(O)R^e,

8) -C _0-6 alkyl-N (R ^e)₂, and

9) A halogen atom,

Wherein alkyl is unsubstituted or substituted with one to three halogens, or wherein two R ^b substituents, together with the atoms to which they are attached, may be cyclized to form a monocyclic C _3-6 cycloalkyl or a monocyclic C _2-6 cycloheteroalkyl ring;

Each R ^c is independently selected from the group consisting of:

1) The hydrogen is used to produce a hydrogen gas,

2) A C _1-6 -alkyl group, a group containing a hydroxyl group,

3) -C _0-6 alkyl-O-C _1-6 alkyl,

4) -A C _0-6 alkyl-OH group,

5) C _0-6 alkyl-S (O) _vR^f,

6) C _0-6 alkyl-S (O) _vN(R^g)₂,

7) -C _1-6 alkyl C (O) -N (R ^g)₂,

8) C _1-6 alkyl N (R ^g)C(O)R^g,

9) -C _0-6 alkyl-N (R ^g)₂, and

10 A) a halogen, a halogen atom,

Wherein alkyl is unsubstituted or substituted with one to three halogens;

Each R ^d is independently selected from the group consisting of:

1) Hydrogen, and

2) A C _1-6 -alkyl group, a group containing a hydroxyl group,

Wherein each alkyl is unsubstituted or substituted with one to three halogens;

Each R ^e is independently selected from the group consisting of:

1) Hydrogen, and

2) A C _1-6 -alkyl group, a group containing a hydroxyl group,

Wherein each alkyl is unsubstituted or substituted with one to three halogens;

each R ^f is independently selected from the group consisting of:

1) Hydrogen, and

2) A C _1-6 -alkyl group, a group containing a hydroxyl group,

Wherein each alkyl is unsubstituted or substituted with one to three halogens;

each R ^g is independently selected from the group consisting of:

1) Hydrogen, and

2) A C _1-6 -alkyl group, a group containing a hydroxyl group,

Wherein each alkyl is unsubstituted or substituted with one to three halogens;

each R ^h is independently selected from the group consisting of:

1) Hydrogen, and

2) A C _1-6 -alkyl group, a group containing a hydroxyl group,

Wherein each alkyl is unsubstituted or substituted with one to three halogens;

Each R ⁱ is-C _1-6 alkyl, wherein each alkyl is unsubstituted or substituted with one to three halogens;

each R ^j is independently selected from the group consisting of:

1) The hydrogen is used to produce a hydrogen gas,

2) OH (OH)

3) A C _1-6 -alkyl group, a group containing a hydroxyl group,

Wherein each alkyl is unsubstituted or substituted with one to three halogens;

each R ^k is independently selected from the group consisting of:

1) Hydrogen, and

2) A C _1-6 -alkyl group, a group containing a hydroxyl group,

Wherein each alkyl is unsubstituted or substituted with one to three halogens;

Each R ^l is independently selected from the group consisting of:

1) Hydrogen, and

2) A C _1-6 -alkyl group, a group containing a hydroxyl group,

Wherein each alkyl is unsubstituted or substituted with one to three halogens;

Each r is independently 0,1 or 2;

Each s is independently 0, 1, 2, 3, 4, or 5;

Each t is independently 0,1, 2 or 3;

each u is independently selected from 0,1 or 2; and

Each v is independently selected from 0, 1 or 2.

2. The compound according to claim 1, or a pharmaceutically acceptable salt thereof, wherein

T is CH;

U is CH; and

V is CH.

3. The compound according to claim 1, or a pharmaceutically acceptable salt thereof, wherein

X is CH ₂.

4. The compound according to claim 1, or a pharmaceutically acceptable salt thereof, wherein

Y is O or CH ₂; and

Z is O or CH ₂.

5. The compound according to claim 4, or a pharmaceutically acceptable salt thereof, wherein

Y is CH ₂; and

Z is O.

6. The compound according to claim 1, or a pharmaceutically acceptable salt thereof, wherein

W is O.

7. The compound according to claim 1, or a pharmaceutically acceptable salt thereof, wherein

Q is CR ⁸; and

R ⁸ is hydrogen.

8. The compound according to claim 1, or a pharmaceutically acceptable salt thereof, wherein

R ² is hydrogen; and

R ³ is hydrogen.

9. The compound according to claim 5, or a pharmaceutically acceptable salt thereof, wherein

R ⁵ is-CO ₂ H.

10. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein R ⁴ is selected from the group consisting of:

1) C _1-3 alkyl

2) C ₃ cycloalkyl group, which is a group,

Wherein alkyl and cycloalkyl are unsubstituted or substituted with one to three substituents selected from the group consisting of: halogen and OC _1-3 alkyl.

11. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein R ⁴ is C _1-3 alkyl, wherein alkyl is unsubstituted or substituted with one to three substituents selected from the group consisting of: halogen or OC _1-3 alkyl.

12. The compound according to claim 1, or a pharmaceutically acceptable salt thereof, wherein

R ⁶ is hydrogen; and

R ⁷ is hydrogen.

13. The compound according to claim 1, or a pharmaceutically acceptable salt thereof, wherein

R ⁹ is C _1-6 alkyl, and

R ¹⁰ is C _1-6 alkyl.

14. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein R ¹ is selected from the group consisting of:

1) -a C _3-9 cycloalkyl group,

2) -A C _2-8 cycloheteroalkyl group,

3) Aryl, and

4) A heteroaryl group, which is a group,

Wherein cycloalkyl, cycloheteroalkyl, aryl and heteroaryl are unsubstituted or substituted with one to five substituents selected from R ^a.

15. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein R ¹ is selected from the group consisting of:

1) -C _3-9 cycloalkyl, and

2) -A C _2-8 cycloheteroalkyl group,

Wherein cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with one to five substituents selected from R ^a.

16. The compound according to claim 1, or a pharmaceutically acceptable salt thereof, wherein

T is CH;

U is CH;

v is CH;

x is CH ₂;

Y is O or CH ₂;

z is O or CH ₂;

w is a bond or O;

Q is CR ⁸;

r ¹ is selected from the group consisting of:

1) -a C _3-9 cycloalkyl group,

2) -A C _2-8 cycloheteroalkyl group,

3) Aryl, and

4) A heteroaryl group, which is a group,

Wherein cycloalkyl, cycloheteroalkyl, aryl and heteroaryl are unsubstituted or substituted with one to five substituents selected from R ^a;

R ² is hydrogen;

r ³ is hydrogen;

r ⁴ is selected from the group consisting of:

1) C _1-3 alkyl

2) C ₃ cycloalkyl group, which is a group,

Wherein alkyl and cycloalkyl are unsubstituted or substituted with one to three substituents selected from the group consisting of: halogen and OC _1-3 alkyl;

r ⁵ is-CO ₂ H or tetrazole;

r ⁶ is hydrogen;

r ⁷ is hydrogen;

r ⁸ is hydrogen;

r ⁹ is C _1-6 alkyl, and

R ¹⁰ is C _1-6 alkyl.

17. The compound according to claim 1, or a pharmaceutically acceptable salt thereof, wherein

T is CH;

U is CH;

v is CH;

x is CH ₂;

Y is CH ₂;

Z is O;

w is O;

Q is CR ⁸;

r ¹ is selected from the group consisting of:

1) -a C _3-9 cycloalkyl group,

2) -C _2-8 Cycloheteroalkyl, and

3) An aryl group,

Wherein cycloalkyl, cycloheteroalkyl and aryl are unsubstituted or substituted with one to five substituents selected from R ^a;

R ² is hydrogen;

r ³ is hydrogen;

R ⁴ is C _1-3 alkyl;

R ⁵ is-CO ₂ H;

r ⁶ is hydrogen;

r ⁷ is hydrogen;

r ⁸ is hydrogen;

r ⁹ is C _1-6 alkyl, and

R ¹⁰ is C _1-6 alkyl.

18. The compound according to claim 1, or a pharmaceutically acceptable salt thereof, wherein

T is CH;

U is CH;

v is CH;

x is CH ₂;

Y is CH ₂;

Z is O;

w is O;

Q is CR ⁸;

r ¹ is selected from the group consisting of:

1) -C _3-9 cycloalkyl, and

2) -A C _2-8 cycloheteroalkyl group,

Wherein cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with one to five substituents selected from R ^a;

R ² is hydrogen;

r ³ is hydrogen;

R ⁴ is C _1-3 alkyl;

R ⁵ is-CO ₂ H;

r ⁶ is hydrogen;

r ⁷ is hydrogen;

r ⁸ is hydrogen;

r ⁹ is C _1-6 alkyl, and

R ¹⁰ is C _1-6 alkyl.

19. The compound of claim 1, selected from the group consisting of:

1) (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((S) -pyrrolidin-3-yl) formamidino) -chroman-2-yl) propionic acid;

2) (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((R) -pyrrolidin-3-yl) -formamidino) -chroman-2-yl) propionic acid;

3) (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((3S, 5R) -5- (hydroxymethyl) -pyrrolidin-3-yl) carboxamidino) chroman-2-yl) propionic acid;

4) (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((3R, 5R) -5- (hydroxymethyl) pyrrolidin-3-yl) carboxamidino) chroman-2-yl) propionic acid;

5) (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((S) -azepan-4-yl) formamidino) chroman-2-yl) propionic acid;

6) (S) -2- ((R) -6- (N- ((1S, 4S) -4-aminocyclohexyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) -amino) -2-oxo-ethyleneamino) oxy) propanoic acid;

7) (S) -2- ((R) -6- (N- ((1S, 3S) -3-aminocyclobutyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) -amino) -2-oxoethyleneamino) oxy) propanoic acid;

8) (S) -2- ((R) -6- (N- ((1R, 3R) -3-aminocyclobutyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) -amino) -2-oxoethyleneamino) oxy) propanoic acid;

9) (S) -2- ((R) -6- (N- (3- (aminomethyl) bicyclo [1.1.1] pent-1-yl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

10 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((R) -azepin-3-yl) formamidino) -chroman-2-yl) propionic acid;

11 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((S) -azepan-3-yl) formamidino) -chroman-2-yl) propionic acid;

12 (S) -2- ((R) -6- (N- (1- (aminomethyl) -2-oxabicyclo [2.1.1] hex-4-yl) formamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

13 (S) -2- ((R) -6- (N- (2-azaspiro [3.5] non-7-yl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) -amino) -2-oxoethyleneamino) oxy) propionic acid;

14 (S) -2- ((R) -6- (N- (2-azaspiro [3.3] hept-6-yl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) -amino) -2-oxoethyleneamino) oxy) propionic acid;

15 (S) -2- ((R) -6- (N- (5-aminobicyclo [3.1.1] hept-1-yl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

16 (2S) -2- ((2R) -6- (N- ((1S, 5R) -3-azabicyclo [3.2.0] hept-6-yl) formamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

17 (S) -2- ((R) -6- (N- ((4R, 6S) -1-azaspiro [3.3] hept-6-yl) formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxo-ethylene) amino) oxy) propionic acid;

18 (S) -2- ((R) -6- (N- ((4S, 6R) -1-azaspiro [3.3] hept-6-yl) formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxo-ethylene) amino) oxy) propionic acid;

19 (S) -2- ((R) -6- (N- ((2S, 4R) -6-azaspiro [3.5] non-2-yl) formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethylene) amino) oxy) propionic acid;

20 (S) -2- ((R) -6- (N- ((2R, 4S) -6-azaspiro [3.5] non-2-yl) formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethylene) amino) oxy) propionic acid;

21 (S) -2- ((R) -6- (N- (7-azaspiro [3.5] non-2-yl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

22 (S) -2- ((R) -6- (N- ((2R, 4S) -6-azaspiro [3.4] oct-2-yl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

23 (S) -2- ((R) -6- (N- ((2S, 4R) -6-azaspiro [3.4] oct-2-yl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

24 (S) -2- ((R) -6- (N- ((1S, 2R,5R, 6R) -5-aminobicyclo [4.1.0] hept-2-yl) formamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

25 (S) -2- ((R) -6- (N- ((1R, 2R,5S, 6S) -5-aminobicyclo [4.1.0] hept-2-yl) formamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethylene) amino) oxy) propanoic acid;

26 (S) -2- ((R) -6- (N- ((1S, 2S,5R, 6R) -5-aminobicyclo [4.1.0] hept-2-yl) formamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

27 (S) -2- ((R) -6- (N- ((1R, 2S,5S, 6S) -5-aminobicyclo [4.1.0] hept-2-yl) formamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethylene) amino) oxy) propanoic acid;

28 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- (piperidin-4-yl) formamidino) chroman-2-yl) propionic acid;

29 (S) -2- ((R) -6- (N- (1- ((R) -3-amino-2-hydroxypropyl) piperidin-4-yl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

30 (S) -2- ((R) -6- (N- (1- ((S) -3-amino-2-hydroxypropyl) piperidin-4-yl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

31 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((R) -azepin-4-yl) carboxamidino) chroman-2-yl) propionic acid;

32 (S) -2- ((R) -6- (N- ((1R, 4R) -4-aminocyclohexyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) -amino) -2-oxoethyleneamino) oxy) propanoic acid;

33 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) -amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((3R, 5S) -5- (hydroxymethyl) pyrrolidin-3-yl) carboxamidino) chroman-2-yl) propionic acid;

34 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((1R, 4R) -4- (methylamino) cyclohexyl) -formamidino) chroman-2-yl) propionic acid;

35 (S) -2- ((R) -6- (N- (4-aminobicyclo [2.2.2] oct-1-yl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

36 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- (azetidin-3-yl) formamidino) chroman-2-yl) propionic acid;

37 (S) -2- ((R) -6- (N- ((1R, 5S, 6S) -3-azabicyclo [3.1.0] hex-6-yl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

38 (S) -2- ((R) -6- (N- (4- (aminomethyl) phenyl) formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

39 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((R) -piperidin-3-yl) formamidino) -chroman-2-yl) propionic acid;

40 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((S) -piperidin-3-yl) formamidino) -chroman-2-yl) propionic acid;

41 (S) -2- ((R) -6- (N- ((1S, 4S) -4- (aminomethyl) cyclohexyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

42 (S) -2- ((R) -6- (N- ((1R, 4R) -4- (aminomethyl) cyclohexyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

43 (S) -2- ((R) -6- (N- ((2S, 4R) -6-azaspiro [3.4] oct-2-yl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

44 (S) -2- ((R) -6- (N- ((2R, 4S) -6-azaspiro [3.4] oct-2-yl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

45 (S) -2- ((R) -6- (N- ((1R, 3S) -3-aminocyclopentyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

46 (S) -2- ((R) -6- (N- ((1S, 3R) -3-aminocyclopentyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

47 (S) -2- ((R) -6- (N- ((1S, 3S) -3-aminocyclopentyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

48 (S) -2- ((R) -6- (N- ((1R, 3R) -3-aminocyclopentyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

49 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((S) -3, 3-dimethylpiperidin-4-yl) carboxamidino) chroman-2-yl) propionic acid;

50 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((R) -3, 3-dimethylpiperidin-4-yl) carboxamidino) chroman-2-yl) propionic acid;

51 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((3R, 4S) -3- (hydroxymethyl) -piperidin-4-yl) carboxamidino) chroman-2-yl) propionic acid;

52 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((3S, 4R) -3- (hydroxymethyl) -piperidin-4-yl) carboxamidino) chroman-2-yl) propionic acid;

53 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((2S, 4S) -2- (hydroxymethyl) -piperidin-4-yl) carboxamidino) chroman-2-yl) propionic acid;

54 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((2R, 4R) -2- (hydroxymethyl) -piperidin-4-yl) carboxamidino) chroman-2-yl) propionic acid;

55 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((2R, 4R) -2-methylpiperidin-4-yl) carboxamidino) chroman-2-yl) propionic acid;

56 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((2S, 4S) -2-methylpiperidin-4-yl) carboxamidino) chroman-2-yl) propionic acid;

57 (S) -2- ((R) -6- (N- ((1R, 4R) -4-amino-4-methylcyclohexyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

58 (S) -2- ((R) -6- (N- ((1S, 4S) -4-amino-4-methylcyclohexyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

59 (S) -2- ((R) -6- (N- ((1S, 4S) -4- (aminomethyl) -4-hydroxycyclohexyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

60 (S) -2- ((R) -6- (N- ((1R, 4R) -4- (aminomethyl) -4-hydroxycyclohexyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

61 (S) -2- ((R) -6- (N- ((2R, 4R, 6R) -6-aminospiro [3.3] hept-2-yl) formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

62 (S) -2- ((R) -6- (N- ((2S, 4S, 6S) -6-aminospiro [3.3] hept-2-yl) formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

63 (S) -2- ((R) -6- (N- ((1S, 4S) -4-amino-4- (2-methoxyethyl) cyclohexyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

64 (S) -2- ((R) -6- (N- ((1R, 4R) -4-amino-4- (2-methoxyethyl) cyclohexyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

65 (S) -2- ((R) -6- (N- ((1S, 4S) -4-amino-4- (2-hydroxyethyl) cyclohexyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

66 (S) -2- ((R) -6- (N- ((1R, 4R) -4-amino-4- (2-hydroxyethyl) cyclohexyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

67 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- (trans-3- (methylamino) cyclobutyl) -formamidino) chroman-2-yl) propionic acid;

68 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- (cis-3- (methylamino) cyclobutyl) -formamidino) chroman-2-yl) propionic acid;

69 (S) -2- ((R) -6- (N- ((1R, 4R) -4-amino-4- (hydroxymethyl) cyclohexyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

70 (S) -2- ((R) -6- (N- ((1S, 4S) -4-amino-4- (hydroxymethyl) cyclohexyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

71 (S) -2- ((R) -6- (N- ((1R, 4R) -4-amino-1-methylcyclohexyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

72 (S) -2- ((R) -6- (N- ((1S, 4S) -4-amino-1-methylcyclohexyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

73 (S) -2- ((R) -6- (N- ((1S, 4S) -4- (aminomethyl) -4-methoxycyclohexyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

74 (S) -2- ((R) -6- (N- ((1R, 3R) -3-amino-3-methylcyclobutyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

75 (S) -2- ((R) -6- (N- ((1S, 3S) -3-amino-3-methylcyclobutyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

76 (S) -2- ((R) -6- (N- ((1R, 5S, 8S) -3-azabicyclo [3.2.1] oct-8-yl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

77 (S) -2- ((R) -6- (N- ((1R, 5S, 8R) -3-azabicyclo [3.2.1] oct-8-yl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

78 (S) -2- ((R) -6- (N- ((1R, 3R) -3- (aminomethyl) -3- (hydroxymethyl) cyclobutyl) -formamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethylene) amino) -oxy) propionic acid;

79 (S) -2- ((R) -6- (N- ((1S, 3S) -3- (aminomethyl) -3- (hydroxymethyl) cyclobutyl) -formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

80 (S) -2- ((R) -6- (N- ((1S, 3S) -3- (aminomethyl) -3-hydroxycyclobutyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

81 (S) -2- ((R) -6- (N- ((1R, 3R) -3- (aminomethyl) -3-hydroxycyclobutyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

82 (S) -2- ((R) -6- (N- ((1R, 3R) -3- (aminomethyl) -3-methoxycyclobutyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

83 (S) -2- ((R) -6- (N- ((1S, 3S) -3- (aminomethyl) -3-methoxycyclobutyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

84 (S) -2- ((R) -6- (N- ((1R, 3R) -3-amino-1-methylcyclobutyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

85 (S) -2- ((R) -6- (N- ((1S, 3S) -3-amino-1-methylcyclobutyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

86 (S) -2- ((R) -6- (N- ((1S, 3S) -3-amino-3- (2-hydroxyethyl) cyclobutyl) carboxamidino) -chroman-2-yl) -2- (((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethylene) amino) oxy) propionic acid;

87 (S) -2- ((R) -6- (N- ((1R, 3R) -3-amino-3- (2-hydroxyethyl) cyclobutyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

88 (S) -2- ((R) -6- (N- ((1R, 3R) -3-amino-3- (hydroxymethyl) cyclobutyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

89 (S) -2- ((R) -6- (N- ((1S, 3S) -3-amino-3- (hydroxymethyl) cyclobutyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

90 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((1R, 3R) -3- (hydroxymethyl) -3- (methylamino) cyclobutyl) chroman-2-yl) propionic acid;

91 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((1S, 3S) -3- (hydroxymethyl) -3- (methylamino) cyclobutyl) chroman-2-yl) propionic acid;

92 (S) -2- ((R) -6- (N- ((1R, 3R) -3-amino-3- (2-methoxyethyl) cyclobutyl) carboxamidino) -chroman-2-yl) -2- (((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

93 (S) -2- ((R) -6- (N- ((1S, 3S) -3-amino-3- (2-methoxyethyl) cyclobutyl) carboxamidino) -chroman-2-yl) -2- (((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethylene) amino) oxy) propionic acid;

94 (S) -2- ((R) -6- (N- ((1S, 3R) -3-amino-3- ((S) -2, 3-dihydroxypropyl) cyclobutyl) -formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

95 (S) -2- ((R) -6- (N- ((1R, 3R) -3-amino-3- ((R) -2, 3-dihydroxypropyl) cyclobutyl) -formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

96 (S) -2- ((R) -6- (N- ((1R, 3S) -3-amino-3- ((S) -2, 3-dihydroxypropyl) cyclobutyl) -formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

97 (S) -2- ((R) -6- (N- ((1S, 3S) -3-amino-3- ((R) -2, 3-dihydroxypropyl) cyclobutyl) -formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

98 (S) -2- ((R) -6- (N- ((1S, 3R) -3-amino-3- ((S) -1, 2-dihydroxyethyl) cyclobutyl) -formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

99 (S) -2- ((R) -6- (N- ((1R, 3R) -3-amino-3- ((R) -1, 2-dihydroxyethyl) cyclobutyl) -formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

100 (S) -2- ((R) -6- (N- ((1S, 3S) -3-amino-3- ((R) -1, 2-dihydroxyethyl) cyclobutyl) -formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

101 (S) -2- ((R) -6- (N- ((1R, 3S) -3-amino-3- ((S) -1, 2-dihydroxyethyl) cyclobutyl) -formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

102 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((1S, 4S) -4- ((methylamino) methyl) -cyclohexyl) carbamimidoyl) chroman-2-yl) propionic acid;

103 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((1R, 4R) -4- ((methylamino) methyl) cyclohexyl) carbamimidoyl) chroman-2-yl) propionic acid;

104 (S) -2- ((R) -6- (N- ((1R, 4S) -4-aminocycloheptyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

105 (S) -2- ((R) -6- (N- ((1R, 4R) -4-aminocycloheptyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

106 (S) -2- ((R) -6- (N- ((1S, 4S) -4-aminocycloheptyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

107 (S) -2- ((R) -6- (N- ((1S, 4R) -4-aminocycloheptyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

108 (S) -2- ((R) -6- (N- ((1R, 3R) -3-aminocyclohexyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

109 (S) -2- ((R) -6- (N- ((1S, 3S) -3-aminocyclohexyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

110 (S) -2- ((R) -6- (N- ((1R, 3S) -3-aminocyclohexyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

111 (S) -2- ((R) -6- (N- ((1S, 3R) -3-aminocyclohexyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

112 (S) -2- ((R) -6- (N- ((1S, 3S) -3- (aminomethyl) cyclobutyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

113 (S) -2- ((R) -6- (N- ((1R, 3R) -3- (aminomethyl) cyclobutyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

114 (S) -2- ((R) -6- (N- ((1S, 3S) -3-amino-2, 2-dimethylcyclobutyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

115 (S) -2- ((R) -6- (N- ((2S, 4S, 7S) -2-aminospiro [3.5] non-7-yl) formamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

116 (S) -2- ((R) -6- (N- ((2R, 4R, 7R) -2-aminospiro [3.5] non-7-yl) formamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

117 (S) -2- ((R) -6- (N- ((1S, 3S) -3- (aminomethyl) -3-methylcyclobutyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

118 (S) -2- ((R) -6- (N- ((1R, 3R) -3- (aminomethyl) -3-methylcyclobutyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

119 (S) -2- ((R) -6- (N- (6- (aminomethyl) -6-fluoropiro [3.3] hept-2-yl) formamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethylene) amino) oxy) propionic acid;

120 (S) -2- ((R) -6- (N- ((1R, 3S) -3- (aminomethyl) -2, 2-dimethylcyclobutyl) -formamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethylene) amino) oxy) propionic acid;

121 (2S) -2- ((2R) -6- (N- (6- (aminomethyl) spiro [3.3] hept-2-yl) formamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

122 (2S) -2- ((2R) -6- (N- ((1S) -1-aminopro [2.3] hex-5-yl) formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethylene) amino) oxy) propionic acid;

123 (2S) -2- ((2R) -6- (N- ((1R) -1-aminopro [2.3] hex-5-yl) formamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethylene) amino) oxy) propionic acid;

124 (S) -2- ((R) -6- (N- ((1S, 3S) -3-aminocyclobutyl) formamidino) -5- (methoxymethyl) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

125 (S) -2- ((R) -6- (N- ((1S, 3S) -3-aminocyclobutyl) formamidino) -7- (methoxymethyl) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

126 (S) -2- ((R) -6- (N- ((1S, 4S) -4-amino-1- (methoxymethyl) cyclohexyl) -carbamimidoyl) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

127 (S) -2- ((R) -6- (N- ((1R, 4R) -4-amino-1- (methoxymethyl) cyclohexyl) -carbamimidoyl) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

128 (S) -2- ((R) -6- (N- ((1S, 4S) -4-amino-4- (methoxymethyl) cyclohexyl) -carbamimidoyl) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

129 (S) -2- ((R) -6- (N- ((1R, 4R) -4-amino-4- (methoxymethyl) cyclohexyl) -carbamimidoyl) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

130 (S) -2- ((R) -6- (N- ((1S, 4S) -4- (aminomethyl) -1-methylcyclohexyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

131 (S) -2- ((R) -6- (N- ((1R, 4R) -4- (aminomethyl) -1-methylcyclohexyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

132 (S) -2- ((R) -6- (N- ((1S, 4S) -4- (2-aminoprop-2-yl) cyclohexyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

133 (S) -2- ((R) -6- (N- ((1R, 4R) -4- (2-aminoprop-2-yl) cyclohexyl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

134 (S) -2- ((R) -6- (N- ((1S, 3S) -3-aminocyclobutyl) formamidino) -7-methylchroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

135 (S) -2- ((R) -6- (N- ((1R, 4R) -4-amino-4- (hydroxymethyl) -1-methylcyclohexyl) -carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethylene) amino) oxy) propionic acid;

136 (S) -2- ((R) -6- (N- ((1R, 3R, 5S) -8-azabicyclo [3.2.1] oct-3-yl) carboxamidino) -chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propionic acid;

137 (S) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) -azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) -2- ((R) -6- (N- ((3S, 5S) -5- (hydroxymethyl) pyrrolidin-3-yl) carboxamidino) chroman-2-yl) propionic acid;

138 (S) -2- ((R) -6- (N- (1- (2-aminoethyl) cyclopropyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

139 (S) -2- ((R) -6- (N- (1- (3-aminopropyl) cyclopropyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid; and

140 (S) -2- ((R) -6- (N- (1- (2-aminoethyl) cyclobutyl) carboxamidino) chroman-2-yl) -2- ((((Z) -1- (2-aminothiazol-4-yl) -2- (((S) -2, 2-dimethyl-4-oxo-1- (sulfonyloxy) azetidin-3-yl) amino) -2-oxoethyleneamino) oxy) propanoic acid;

Or a pharmaceutically acceptable salt thereof.

20. The compound of claim 1, selected from the group consisting of:

Or a pharmaceutically acceptable salt thereof.

21. A pharmaceutical composition comprising a therapeutically effective amount of a compound according to claim 1, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

22. The pharmaceutical composition of claim 21, further comprising a therapeutically effective amount of a β -lactamase inhibitor compound.

23. The pharmaceutical composition of claim 22, wherein the β -lactamase inhibitor compound is selected from the group consisting of riliebactam, tazobactam, clavulanic acid, sulbactam, abamectin, taybobalamin, naltrexone, feb-bactam, ji Da-baran, emtricobalamin, and dulobalamin.

24. A method of treating a bacterial infection comprising administering to a subject in need of such treatment a therapeutically effective amount of a compound of claim 1 or a pharmaceutically acceptable salt thereof.

25. The method of claim 24, further comprising administering to a subject in need of such treatment a therapeutically effective amount of a β -lactamase inhibitor compound.

26. The method of claim 25, wherein the β -lactamase inhibitor compound is selected from the group consisting of riliebactam, tazobactam, clavulanic acid, sulbactam, abamectin, tazobactam, naltrexone, fazobactam, ji Da-bartane, emtricobalamin, and dulobalamin.

27. The method of claim 24, wherein the bacterial infection is caused by a pseudomonas species, a klebsiella species, an enterobacter species, an escherichia species, a morganella species, a citrobacter species, a serratia species, or an acinetobacter species.

28. Use of a compound according to claim 1, or a pharmaceutically acceptable salt thereof, for the treatment of a bacterial infection or for the manufacture of a medicament for the treatment of a bacterial infection.

29. The use of claim 28, further comprising administering a compound of claim 1 in combination with a β -lactamase inhibitor compound for treating a bacterial infection or in combination with a β -lactamase inhibitor compound for the manufacture of a medicament for treating a bacterial infection.

30. The use of claim 29, wherein the β -lactamase inhibitor compound is selected from the group consisting of riliebactam, tazobactam, clavulanic acid, sulbactam, abamectin, tazobactam, naltrexone, fazobactam, ji Da-bartane, emtricobalamin, and dulobalamin.

31. The use of claim 29, wherein the bacterial infection is caused by a pseudomonas species, a klebsiella species, an enterobacter species, an escherichia species, a morganella species, a citrobacter species, a serratia species, or an acinetobacter species.