GB2184440A - Fluoralkylatedcarbapenem derivatives - Google Patents

Description

SPECIFICATION Fluoralkylatedcarbapenem derivatives The present invention concerns 6- (1'-fluorethyl)- and 6- (1'-fluoro-1'-methylethyl)-carbapen- ems, processes for their production and their use as chemotherapeutics.

EP10317 discloses a very wide range of carbapenem derivatives having antibiotic activity but makes no mention of the fluoralkylated compounds of the present invention and their advantageous antibiotic properties.

More particularly the invention concerns compounds of formula I

wherein, R1 represents hydrogen or methyl, R2 represents hydrogen or lower alkyl, lower alkenyl or cycloalkyl each of which may be unsubstituted or mono-or poly-substituted by amino, monoor di- (lower)-alkylamirio, lower acylamino, carboxy, lower alkoxycarbonyl or carbamoyl ; a group of formula llc (CH2) p-R5 lic wherein R5 represents phenyl or a 5-or 6-membered saturated or unsaturated heterocycle containing one or more heteroatoms selected from 0, S and/or N and which may be unsubstituted or mono-or poly-substituted by fluoro, chloro, bromo, amino, mono-or di-(lower)-alkylam- ino, hydroxy, lower alkoxy, mercapto, alkylthio, phenylthio, sulfamoyl, guanidino, nitro, cyano, lower acylamino, carboxy, alkoxycarbonyl or carbamoyl and p is 0,1,2 or 3; or a group of formula

wherein R6, R7 and R8 may be the same or different and each represents hydrogen or lower alkyl or R6 and R8 and/or R, and one of the CH2 groups may be joined to form a ring as may R, and RB in formula 11 and R6 and R, in Ila and llb, which rings may be unsubstituted or mono-or poly-substituted by alkyl, hydroxy, carboxy or di-(lower)-alkyl-amino, m is 2 or 3, and n is 1,2 or 3 R3 represents hydrogen or lower alkyl and R4 represents lower alkyl, or protected forms and/or physiologically hydrolysable and acceptable ester forms thereof; in free acid or salt form or in the form of zwitter-ions.

The compounds of the invention may be prepared A) by introducing a group-S-R2 into a compound of formula III

wherein R, to R4 are as defined above, Rro represents a leaving group Rg represents a protecting group or a physiologically hydrolysable and acceptable ester group or B) by exchanging the OH group in a compound of formula IV

or a precursor thereof for fluoro, whereby in formula IV, R, to R4 and R9 are as defined above, and if required deprotecting a compound thus obtained or if required converting a compound thus obtained into or into another physiologically hydrolysable-and acceptable-ester form and/or protected form thereof and recovering the compound thus obtained in free acid or salt form or in the form of a zwitterion.

Process A) may be carried out in conventional manner for example in an inert solvent such as an aromatic hydrocarbon e. g. benzene; or acetonitrile and preferably at reduced temperatures e. g. ca 0 C.

Process B) may be carried out in conventional manner e. g. employing a dialkylaminosulfurtrifluoride such as diethylaminosulfurtrifluoride.

The removal of protecting groups is carried out in conventional manner as is the isolation and purification of the products obtained.

The preparation and interconversion of ester, protected and salt forms is also carried out in conventional manner.

Processes for preparing carbapenems in their various forms are also described in the literature, for example in European Patent Application Publications 1628,10316,10317,17992,37080, 37081,38869,50334,33209,44142,60612,61231,44170,59478,58317 and can where appropriate be employed analogously for preparing compounds according to the invention.

The starting materials of formula III are new and can be prepared by introducing the group Rl, into a compound of formula V

wherein R1, R3, R4, Rg and R, o are as defined above.

Examples of leaving groups Rlo are those formed by reaction of the hydroxy group with a phosphoricacidester chloride e. g. with phosphoric acid diphenyl-ester chloride or with a sulphonic acid e. g. with p-toluene sulphonic acid.

The compounds of formula IV can be prepared analogously to process A) above from compounds of formula Va

The process is conventional and comprises introduction of the group R, o and replacement of this by the group-S-R2.

The compounds of formula V are also new and can be prepared for example according to the following reaction schemes or analogously to methods described in the above mentioned reaction schemes.

RECTION SCHEME 1

REACTION SCHEME 2

continue as in reaction scheme li).

The reactions shown in these schemes can be carried out using procedures conventional for the type of reaction involved. Cyclisation can for example be carried out in an inert solvent such as an aromatic hydrocarbon e. g. benzene in the presence of a transitional metal catalyst.

Examples of a transitional metal catalyst are rhodium ll)-acetate or copper acetylacetonate.

The compounds of formula V and Va can exist in the following tautomeric forms

The remaining intermediates are either known or can be prepared analogously to known methods and/or described hereinafter in the examples.

Carbapenems such as those of the present application contain 2 centres of chirality in the beta-lactam ring (5 and 6)

They can be present in the various configurations as 6R, 5R-, 6S, 5R-, 6R, 5S- or 6S, 5S-isomers or as mixtures thereof. When R3 and R4 are different a further assymetric carbon atom exists at position 4 and this has preferably the R-configuration. When the starting materials employed are in a particular configuration the end products obtained will have the same configuration and mixed starting materials will produce mixed end products. The configuration of these compounds thus does not alter during reactions such as A) or B) above. Mixtures of isomers can be separated by conventional methods such as fractional crystallisation.

It is known that the biological activity can be attributed to compounds, wherein the 5-position is in R-configuration.

A further centre of chirality is present when R, is hydrogen and this also remains unaffected during reactions such as A) above. In reactions such as B), however, where fluorine is introduced, inversion occurs. Thus fluorination of an 8-R-hydroxy starting material will yield an 8-S-fluoro end product and vice-versa.

The compounds of formula I in free form or physiologically-hydrolysable and acceptable ester form exhibit chemotherapeutic, in particular anti-microbial activity as indicated by their inhibiting effect against various bacteria, e. g. Pseudomonas aeroginosa, Enterobacter cloacae, Enterobacter agglomerans, Staphylococcus epidermidis, Streptococcus aronson, Streptococcus pneumoniae, Aerococcus viridans, Staphylococcus aureus, Streptococcus pyogenes, Streptococcus faecalis, Escherichia coli, Proteus vulgaris, Proteus mirabilis, Proteus morganii, Klebsiella pneumoniae, Serratia marcescens and Salmonella typhimurium in vitro in series dilution tests at concentrations of, for example, 0.001 to 50 ug/ml, and in vivo in the mouse at dosages of, for example, about 0.1 to 100mg/kg of animal body weight.

The compounds also possess an inhibiting effect against sslactamases at concentration between 0.1 and 10 ug/ml. The enzymatic activity of ss-lactamase-preparations of gram-positive and gram-negative bacteria may be tested using the chromogenic substrate Nitrocefin (Lit: C. H.

O'Callaghan et. al., Novel method for detection of ssiactamases by using a chromogenic cephalosporin substrate; Antimicrobial Agents and Chemotherapy, Vol. 1, No. 4,283-288/1972). The inhibition of ss-íactamase is tested in 0.1 M phosphatebuffer (pH=7.0) using the same substrate.

The enzymes are preincubated together with the inhibitors at appropriate concentrations at 25 C or the inhibitors and the substrate (Nitrocefin) are added simultaneously and the inhibition of substratehydrolysis caused by the inhibitors in comparison to the noninhibited hydrolysis is measured. The activity is expressed in % inhibition or in ICsO (=concentration of inhibitor, which inhibits 50% of the enzyme).

This inhibiting effect is also noticeable in the marked synergism demonstrated with other fl- lactam antibiotics against ss-lactamase producing bacteria. The compounds of the present invention are stable to sslactamases.

The compounds are therefore indicated for use as chemotherapeutics in particular as antibacterially active antibiotics.

An indicated suitable daily dosage for use as an antibacterially active anti-biotic is from about 1 to 6g. If desired this may be administered in divided doses 2 to 4 times a day in unit dosage form containing from about 250 to 3000mg of the compound or in sustained release form.

Compounds which contain a free salt forming group can be employed in this form or in the form of a chemotherapeutically accpetable salt thereof, which forms have the same order of activity as the free forms. Suitable salt forms include alkali and alkaline earth metal and ammonium or amino acid salt forms.

Compounds may be admixed with conventional chemotherapeutically acceptable diluents and carriers, and administered in such forms as tablets or capsules or parenterally. Such compositions also form part of the invention.

The invention therefore also concerns a method of combating bacteria comprising administering to a subject in need of such treatment an effective amount of a compound of formula I or a chemotherapeutically acceptable salt thereof and such compounds for use as chemotherapeutic agents, in particular anti-bacterially active antibiotics.

Lower alkyl moieties contain 1 to 6 (e. g. 1-4) esp. 1 or 2 carbon atoms. Correspondingly alkenyl and alkynyl moieties contain 2 to 4 particularly 2 or 3 carbon atoms. Cycloalkyl groups contain preferably 3 to 6 carbon atoms.

By lower acylaminoalkyl is to be understood e. g.-CH2CH2. NH. CO.-C2H5,-CH3 ; -CH2CH2. NH. CO. CH2'C6H5 ;-CH2CH,. NH. CO. CH, CH2. NH2 ;-CH2CH2. NH. CO. CH2. NH2.

Heterocycles as R, include e. g.

and morpholino.

Protecting groups are those conventionally employed in antibiotics chemistry to protect OH, NH2 and COOH groups. They include p-nitrobenzyi, p-nitrobenzyloxycarbonyl, t-butyl-dimethylsilyl, trimethylsilyl.

Physiologically hydrolysable-and acceptable-ester groups (also known as easily cleavable ester groups) are those which are hydrolysable under physiological conditions to yield acids which are themselves physiologically acceptable, such esters include acetoxymethyl, 1-acetoxyethyl, 1ethoxycarbonyloxyethyl, 5-indanyi or preferably, pivaloyloxymethyl, hexanoyloxymethyl, phthalidyl, ethoxycarbonylmethoxymethyl or 3-ethoxycarbonyl-1-acetonyl.

It will be appreciated that certain protecting groups can also be physiologically hydrolysableand acceptable-groups and vice versa.

Preferred substituents are R, =a) H; b) CH3 R2=a) lower alkyl optionally mono-or di-substituted by amino, mono-or di-lower alkylamino, acylamino, carboxy b)- (CH2) p-R5 c) lI, Ila or llb preferably Ila R3=H R4=CH3 R5=a) individual heterocycles as listed above b) methyltetrazolyl, morpholinyl R6, R7, R8 =a) H, alkyl especially methyl b) =closed rings p=0, 1,2,3 preferably 0 or 2 m=2 or 3 preferably 2 n= 1,2, or 3 preferably 1.

Combinations of these meanings and the preferred forms thereof are especially interesting.

Examples are R, =hydrogen or methyl ; R2=lower alkyl optionally mono-or di-substituted by carboxy, amino, mono-and or di-lower alkyl amino or acylamino ; or-(CH2) pR5 is a heterocycle, e. g. methyltetrazolyl.

A further example is R, =hydrogen ; R2=amino (lower) alkyl, (CH2) pR5 wherein R5 represents me thyltetrazolyl and p is 2 or Ila wherein R6, R7 and R8=CH3 and m is 1, R3=H, R4=CH3.

A particularly preferred single compound is (4R, 5R, 6R)-1-aza-6- [1 (R)-fluorethyl]-4-methyl- 7-oxo-3 [ (N, N, N'-trimethylcarbamidino) methyl] thio-bicyclo [3.2.0] hept-2-ene-2-carboxylic acid in free form or in the form of a physiologically-hydrolysable and acceptable ester. of a salt or of a zwitter-ion.

The following examples illustrate the invention whereby temperatures are expressed in degrees centigrade.

Example 1 : (5RS, 6RS)-3- (2-aminoethylthio)-1-aza-6- [1 (RSJ-fluorethyl]-4-methyl-7-oxobicy- clo [3. 2. Ojhept-2-ene-2-carboxylic acid a) To an ice-cold solution of 130mg of (5RS, 6RS)-1-aza-3, 7-dioxo-6- [l (RS)-fluorethyl]- 4-methyl-bicyclo [3.2.0] heptane-2-carboxylic acid. 4-nitrobenzylester in 20mut of dichloromethane are added 0.13moi of ethyl diisopropylamine followed by 146, ul of phosphoric acid diphenyl ester chloride. After 15 minutes at 0 a further 0.13ml of ethyl diisopropylamine are added followed by 90mg of 4-nitrobenzyloxycarbonyl-cysteamine in 5ml of dichloromethane. Stirring is continued for 1 hour at 0 and the reaction mixture then partitioned between ethyl acetate and saturated aqueous NaCI. After drying over MgS04 the organic phase is evaporated to dryness and the residue chromatographed over silica gel (eluant : dichloromethane/ether=10/1).

(5RS, 6RS)-1-aza-6- [1 (RS)-fluorethyl]-4-methyl-3- [2- (4-nitrobenzyloxycarbonyl) aminoethyl- thio]-7-oxo-bicyclo [3.2.0] hept-2-ene-2-carboxylic acid. 4nitrobenzylester is obtained. NMR (CDCI3) : 1.18-1.40 (m4.5); 1.50-1.66 (m, 1.5); 2.69-3.60 (m, 6); 4.06 (dd, 1, J=9,2.5Hz); 4.48-4.80 (m, 0.5); 5,00-5.40 (m, 4.5); 7.53 (d, 2, J=9Hz); 7.56 (d, 2, J=9Hz); 8.25 (d, 2, J=9Hz); 8.28 (d, 2, J=9Hz). b) A suspension of 0. 1g of (5RS, 6RS)-1-aza-6- [1 (RS)-fluorethyl]-4-methyl-3- [2- (4-nitro- benzyloxycarbonyl) aminoethylthio]-7-oxobicyclo [3.2.0] hept-2-ene-2-carboxylic acid. 4-nitroben zylester and 0. 1g of 10% Pd/C in 5ml of tetrahydrofuran and 5mi phosphate buffer (pH 7) are hydrogenated at 20 and 1 bar hydrogen pressure for 1 hour. After filtration of the catalyst and washing of the residue with buffer the combined filtrates are extracted with ethylacetate and the aqueous phase freeze-dried. This lyophilisate is purified by chromatography over HP-20. Fractions with UV-extinction at 300nm are combined and lyophilised to obtain the title compound.

UV (pH 7 buffer): Amax. =295nm.

The following compounds of formula I may be obtained analogously or as hereinbefore described.

Ex. R 1 R2 R3 R4 Conf. phys. chem. data

Non 1 1 2 H-CH2CH2NN H CH3 4R, 5R, 6R, 8R amorph CH/max 3 H -"- H CH3 4S,5R,6R, 8R amorph # max = 2

RANCH3 4 H CH2. C H CH3 4R, 5R, 6R, 8R amorph 'N (CH-) =295 J /. tnax The 4-nitrobenzylester of the compounds of formula I may be obtained analogously or as hereinbeforedescribed: Ex. COO-R R2 R3 R4 Conf.

NMR Spectra Ex. Spectrum: 2 (D20) 1.11 (d, 3, J=7Hz) ; 1.43 (dd, 3, J=25+6, 5Hz); 2.57 (s, 3); 3.09 (dq, 1, J=9+7Hz); 3.22 (dt, 1, J=15+5Hz); 3.40 (ddd, 1, J=15,8.5+4.5Hz); 3.60 (ddd, 1. J=26.5,5+ 2.5Hz); 3.95 (dd, 1. J=9+2,5Hz); 4.63 (ddd, 1, J=14.5, 8.5+4.5Hz); 4.76 (dt, 1, J=14. 5+5Hz) ; 5.13 (ddq, 1. J=47,7+ 5Hz).

4 (D20) 1.24 (d, 3, J=7Hz) ; 1.44 (dd, 3, J=25+7Hz) ; 3.10 (s, 3); 3.12 (s, 3); 3.34 (s, 3); 3.44 (dq, 1, J=9.5+7Hz); 3.76 (ddd, 1, J=28,5+3Hz); 4.00 (d, 1, J=14Hz) ; 4.06 (d, 1, J=14 Hz); 4.38 (dd, 1, J=9.5+3Hz); 5.16 (ddq, 1, J=48,7+5Hz).

Ex: Spectrum: 5 (CDCí3) 1.18 (d, 3, J=7Hz); 1.48 (dd, 3, J=24,5,6,3Hz); 2.51 (s, 3); 3.20-3.55 (m, 4); 4.12 (dd, 1, J=9, 2, 5Hz); 4.40 (ddd, 1, J=15, 10,6,3Hz); 4.65 (dt, 1, J=15,6,3Hz); 5.00 (d of quint., 1, J= 49,6,3Hz); 5.27 (d, 1, J=13,7Hz); 5.47 (d, 1, J=13,7Hz); 7.65 (d, 2, J=9Hz); 8.26 (d, 2, J=9Hz).

6 (CDCI3) 1.14 (d, 3, J=6,3Hz); 1.48 (dd, 3, J=23,5,7Hz); 3.00-3.20 (m, 7); 3.32 (a, 3); 3.46 (ddd, 1, J=21,3,6,3,2,5Hz); 4.02 (d, 1, J=12, 5Hz); 4.11 (d, 1, J=12, 5Hz); 4.35 (dd, 1, J=10, 2,5Hz); 5.03 (d of quint., 1, J=47, 5,6,3Hz); 5.26 (d, 1, J= 13,8Hz); 5.50 (d, 1, J=13,8Hz); 7.64 (d, 2, J=9Hz); 8.23 (d, 2, J=9Hz); 8.90 (br, 1).

The required starting materials can be prepared as follows : A) (5RS, 6RS)-1-aza-3, 7-dioxo-61 1 (RS)-fluorethyl]-4-methylbicyclo [3. 2.0]-heptane-2-carboxylic acid. 4-nitrobenzylester (for example 1) a) (3RS, 4RS)-3- (1 [RS)-fluorethylj-2-oxoazetidine-4-yl-acetic acid benzylester To a78 cooled solution of 1.5m ! of diethylaminosulphurtrifluoride in 4ml of dry dichloromethane is added a solution of 2.52g of (3RS, 4RS)-3-[1(SR)-hdyroxyethyl]-2-oxoazetidine-4yl-acetic acid benzyl ester (prepared analogously to D. G. Melillo et. al., Tetrahedron Letters 21, 2783 [1980]) in 4ml of abs. dichloromethane. The mixture is stirred for 5 minutes at -78 and mixed with excess cold saturated NaHC03. After addition of further dichloromethane the phases are separated, the organic phase dried over magnesium sulphate and evaporated to dryness.

Chromatography of the residue over silica gel (cyclohexane/ethylacetate=2/1) yields the title compound m. p. 40-43 .

IR (CHCI3) : 1765,1730cm-' NMR (CDCI3) : 1.45 (dd, 3, J=24, 6.5Hz); 2.68 (dd, 1, J=16, 9Hz); 2.86 (dd, 1, J=16, 5.5Hz); 3.01 (ddd, 1, J=18.5,7,2.5Hz); 4.02 (ddd, 1, J=9,5.5,2.5Hz); 4.97 (dq, 1. J=48, 6.5Hz) 5.18 (s, 2); 6.25 (br, 1) ; 7.40 (s, 5). b) 2- [ (3RS, 4RS)-3-fl (RS)-fluorethyll-2-oxazetidine-4-yl] propanoic acid benzyi ester To a-78 cooted soiution of 1. 68ml diisopropylamine in 12. 5ml of abs. tetrahydrofuran are added 12.5m1 of a 1.6 M solution of n-butyl-lithium in hexane. After 20 minutes at -78 1.32g of (3RS, 4RS)-3-[1 (RS)-fluorethyl]-2-oxoazetidine-4-yí-acetic acid benzyl ester are added and after a further 20 minutes 1.87moi of methyliodide. The reaction mixture is stirred for 40 minutes at -78 and then warmed to 0 . The mixture is diluted with 0.1 N HCI and extracted with ethylacetate. The ethylacetate phase is washed once with water and once with saturated NaC) solution, dried over MgS04 and concentrated to dryness. Chromatography of the residue over silica gel (dichloromethane/ethylacetate=50/1) yields the title compound.

NMR (CDCI3) : 1.14-1.34 (m, 4.5); 1.48-1.61 (m, 1.5); 2.53-3.32 (m, 2); 3.57-3.84 (m, 1) ; 4.48-4.62 (m, 0.5); 5.00-5.20 (m, 2.5); 6.33 (br, 1) ; 7.34 (br, s, 5). c) 2 [ (3RS, 4RSJ-3 (1 (RS)-fluorethylJ-2-oxoazetidine-4-yl] propionic acid A mixture of 500mg of the corresponding benzylester and 50mg of 10% Pd/C in 50ml of methanol is hydrogenated at a hydrogen pressure of 1 bar for 1 hour. Filtration and concentration of the filtrate to dryness yields the title compound.

NMR (CDCI3) : 1.17-1.40 (m, 4.5); 1.53-1.67 (m, 1.5); 2.48-3.36 (m, 2); 3.64-4.00 (m, 1) ; 5.105.36 (m, 0.5); 4.00-4.90 (m, 1.5). d) 4 [ (3RS, 4RS)-3- (1 (RS)-fluorethyl]-2-oxoazetidine-4-yl]-3-oxopentanoic acid. 4-nitrobenzy- lester 200mg of 2- [ (3RS, 4RS)-3- [1 (RS)-fluorethyl]-2-oxoazetidine-4-yl] propanoic acid are dissolve in 8ml of tetrahydrofuran, treated at-20 with 280mg of carbonyldiimidazole and stirred for 3 hours at 20 . At the same time 550mg of malonic acid 4-nitrobenzylester and 200moi of magnesium ethoxide are suspended in 8ml of tetrahydrofurane and stirred for 3 hours at RT.

The first solution is then added to the second and the mixture stirred overnight. The result is poured into ether and extracted with 1 N HCI and water. Drying of the organic phase followed by column chromatography of the residue yields the title compound.

NMR (CDCI3) : 1.10-1.34 (m, 4.5); 1.52-1.63 (m, 1.5); 2.44-3.07 (m, 2); 3.48 (s, 0.5); 3.60 (s, 1.5); 3.67-3.95 (m, 1) ; 4.46-4.74 (m, 0.5); 5.04-5.34 (m, 2.5); 6.06 (br, 1) ; 7.52 (d, 2, J=9Hz) ; 8.24 (d, 2, J=9Hz). e) 4- [ (3RS, 4RS)-3- [1 (RS)-fluoroethyl]-2-oxoazetidine-4-yl]-2-diazo-3-oxo-pentanoic acid. 4-nitrobenzylester To an ice cooled solution of 0.16g 4- [ (3RS, 4RS)-3- [ 1 (RS)-fluorethyl]-2-oxoazetidine-4-y- I]-3-oxopentanoic acid. 4-nitrobenzylester and 0.12g of 4-carboxybenzenesulfonylazide in 8ml of acetonitrile are added 0.24ml of triethylamine. After removal of the cooling bath stirring is carried out for 30 minutes at room temperature. The mixture is poured into 100ml of ethyl acetate, washed with 5% NaHCO3 solution and then with water and dried over MgSO4 Removal of the solvent yields the title compound.

NMR (CDCl3) : 1.08-1.40 (m, 4.5) ; 1.53-1.66 (m, 1.5); 2.82-3.20 (m, l) ; 3.46-4.04 (m, 2): 4.92 (dm, 1, J=48. 5Hz): 5.38 2); 5.90.6.20 (br, 1) ; 7.57 (d, 2, J=9Hz); 8.30 (d, 2, J=9Hz). f) (5RS, 6RS)-1-aza-3, 7-dioxo-61 1 (RS)-fluorethyl]-4-methylbicyclo-[3. boxylic acid. 4-nitrobenzylester A suspension of 0.15g of 4- [ (3RS, 4RS)-3- [ 1 (RS)-fluorethyl]-2-oxo-azetidine-4-yl]-2-dia- zo-3-oxopentanoic acid. 4-nitrobenzylester and 3mg of rhodiumacetate in 70ml of benzene is warmed for 20 minutes at 80 under argon. After cooling to room temperature the catalyst is filtered off and the filtrate concentrated to dryness to obtain the title compound.

NMR (CDCI3) : 1.17-1-42 (m, 4.5); 1.50-1-62 (m, 1.5); 2.20-2.98 (m, 1) ; 3.20-3.60 (m, 1 ; 3.78 (dd, 0.75, J=8.5,2Hz); 4.28 (dd, 0.25, J=7.5,2Hz); 4.66-4.94 (m, 1.5); 5.20-5.50 (m, 2.5); 7.57 (d, 2, J=9Hz) ; 8.30 (d, 2, J=9Hz).

B) 4(R)-[(3R,4R)-3-[1(R)-fluorethyl]-2-oxoazetidine-4-yl]-3-oxo-pentanoic acid. 4-nitrobenzyllester and 4 (SJ [ (3R, 4R)-3 [1 (RJ-fluorethylj-2-oxoazetidine-4-ylj-3-oxo-pentanoic acid. 4-nitro- benzylester : a) 6-trans-1 (S)-hydroxyethylpenicillanic acid. benzhydrylester To a solution of 14g of diazopenicillanic acid. benzhydrylester in 50moi of dichlormethane are added 20mg of zinc chloride, the mixture cooled to-10 , 18ml of freshly distilled acetaldehyde slowly added dropwise and the result stirred for a further hour. The reaction mixture is then washed once with pH 7 buffer solution once with saturated NaCI solution, dried over MgSO4, filtered and concentrated. The residual oil is dissolve in 200ml of dry tetrahydrofuran, cooled to -78 , treated with 36ml of Superhydride@ and then stirred for a further 30 minutes. The mixture is then diluted with ethylacetate, washed once with pH 7 buffer, once with water, once with saturated NaCl solution, dried over MgSO4 and after removal of the solvent chromatographed on silica gel (dichloromethane/ether=10/1). The title compound is obtained as a crystalline product m. p. 63-66 .

NMR (CDCl3) : 1.22 (s, 3); 1.34 (d, 3, J=6. 8Hz); 1.60 (s, 3); 2.00 (br, 1) ; 3.40 (dd, 1, J=6. 3,2Hz); 4.06-4.38 (m, 1 ; 4.57 (s, 1) ; 5.28 (d, 1, J=2Hz); 6.95 (s, 1) ; 7.18-7.48 (m, 10). b) 6-trans-1 (R)-fluorethylpenicillanic acid. benzhydrylester To a suspension of 4.33g potassium fluoride in 200ml of dry dichloromethane are added at -78 under argon 10ml of diethylamino sulphurtrifluoride. To this suspension is now added at -78 a chilled solution (-78 ) of 13.5g of 6-trans-1 (S)-hydroxyethylpencillanic acid. benzhydryl- ester. After one hour at -78 the cooling bath is removed and stirring continued for 1 more hour at room temperature. For working-up the mixture is extracted twice with water dried over MgSO4 and concentrated. The residue is chromatographed on silica gel (dichloromethane/petroleum ether=10/3 to obtain the oily title compound.

NMR (CDCI3) : 1.25 (s, 3); 1.47 (dd, 3, J=23.5,6.3Hz); 1.62 (s, 3); 3.47 (ddd, 1, J=20.7,7.2,1.8Hz); 4.59 (s, 1) ; 5.00 (ddq, 1, J=49.6,7.2,6.3Hz); 5.36 (d, 1, J=1.8Hz); 6.97 (s, 1) ; 7.22-7.25 (m, 10). c) 2- 4-acetoxy- (3RJ-3- (1 (R)-fluorethyl)-2-oxoazetidine-1-yl]-3-methyl-2-butenoic acid. benzhydrylester To a solution of 0.98g of 6-trans-1 (R)-fluorethylpenicillanic acid.-benzhydrylester in 30ml of acetic acid are added 2.28g of mercury (II) acetate and stirring carried out for 1 hour at 100 .

After cooling filtration is performed and the filtrate brought to dryness and stirred three more times with toluene. The residue is taken up in ethylacetate and insolubles again filtered off. The filtrate is extracted three times each with 20ml water, dried over MgSO4 and concentrated. The residue is chromatographed on silica gel (dichloromethane/ether=30/1) to obtain the title compound m. p. 102-105 .

IR (CHCI3) : 1770, 1720cm-1. d) 4-Acetoxy- (3RJ-3- (1 (R)-fluorethylJ-2-oxoazetidine Ozone is passed through a solution of 6.2g of 2- [4-acetoxy- (3R)-3- [1 (R)-fluorethyl]-2-ox- oazetidine-1-yl]-3-methyl-2-butenoic acid. benzhydrylester at78 until a permanent blue coiour is achieved. The excess ozone is driven out with nitrogen and 1.75g of dimethylsulphide added. The reaction mixture is allowed to rise to room temperature. The solvent is evaporated on a rotary evaporater, the residue taken up in 100ml of methanol and after addition of 2 drops of triethylamine stirred for 2 hours. After renewed concentration the residue is chromatographed on silica gel (dichloromethane/ethylacetate=10/3) to obtain the oily title compound.

IR (CHCI3) : 3420,1785,1745 cm-'. e) 2 (R) ( (3R, 4R)-3- [1 (fiJ-fluorethyl]-2-oxoazethidine-4-yl] monothiopropanoic acid. S-phenylester and 2 (S)-j (3R, 4R)-3 (1 (R)-fluorethylj-2-oxoazetidine-4-ylJmonothiopropanoic acid. S-phe- nylester To a solution of 1. 8ml of diisopropylamine in 30ml of dry tetrahydrofuran are added at -78 7.79g of butyllithium solution (1.6M) in hexane. After 30 minutes 1.95g of monothiopropanoic acid. S-phenylester in 10mi of tetrahydrofuran are added. The faintly yellow solution is stirred for 30 minutes at -78 , 2. 25ml of trimethylchlorosilane then added the mixture ailowed to rise to room temperature. After removal of the solvent the residue is digested in pentane, filtered under argon and again concentrated. To the remaining yellow liquid are added 5ml of dry acetonitrile and 700mg of 4-acetoxy- (3R)-3- [ 1 (R)-fluorethyl]-2-oxo-azetidine dissolved in 1ml of dry acetonitrile. The solution is cooled to-30 and 0.16ml of trifluoromethanesulfonic acid trimethylsilyl ester injected in. The reaction mixture is allowed to rise to room temperature and stirred for 20 hours at this temperature. It is then poured onto pH 7 buffer and extracted with ethylacetate, dried over Na2SO4 and concentrated. Chromatography over silica gel (ethylacetate/cyclohexane=1/1) yields the title compound as 1: 1 mixture which can be separated by chromatography.

NMR for 2 (R)-isomer (CDCI3) ; 1.34 (d, 3, J=6.5Hz); 1.50 (dd, 3, J=24+6.5Hz); 3.10 (quint., 1, J=6.5Hz); 3.27 (ddd, 1, J=21, 6.5+2Hz); 3.92 (dd, 1, J=6.5+2Hz); 4.97 (d of quint., 1, J=48.5+6.5Hz); 6.28 (br, 1) ; 7.44 (s, 5).

NMR for 2 (S)-isomer (CDCI3) : 1.39 (d, 3, J=7Hz); 1.50 (dd, 3, J=24.5+6.3Hz); 2.90 (dq, 1, J=9+7Hz); 3.01 (dddd, 1, J=17, 8.5,2+0.5Hz); 3.80 (dd, 1, J=9+2Hz) ; 4.93 (ddq, 1, J=48. 5,8.5+6.3Hz); 6.26 (br, 1) ; 7.46 (s, 5). f) 2a(R)-[(3R,4R)-3-[1(R)-fluorehtyl]-2-oxoazetidine-4-yl]propanoic acid and 2(S)-[(3R,4R)-3-[(1(R)-fluorethyl]-2-oxoazetidine-4-yl]propanoic acid A mixture of 290mg of 2 (R)- [ (3R, 4R)-3- [l (R)-fluorethyl]-2-oxoazetidine-4-yl] monothiopropanoic acid. S-phenylester and 2 (S)- [ (3R, 4R)-3- [1 (R)-fluorethyl]-2-oxoazetidine-4-yl] monothiopropanoic acid. S-phenylester and 430mg of mercury (II) trifluoroacetate in 5ml of dichloromethane is stirred for 4 hours at room temperature. The result is concentrated to dryness and the residue taken up in 10mi of ice/water. After adjustment of pH to 8.5 (1N NaOH) stirring at room temperature is carried out until the pH value no longer changes. The mixture is then extracted once with ethylacetate and the aqueous phase adjusted to pH 2 and again extracted with ethylacetate. After drying and concentration of this phase the mixture of the title compounds remains, which can be directly further employed. g) 49R)-[(3R,4R)-3-[1(R)-fluorethyl]-2-oxoazetidine-4-yl]-3-oxopentanoic acid. 4-nitrobenzylester and 4(S0-[(3R,4R)-3-[1(R)-fluorethyl]-2-oxoazetidine-4-yl]-3-oxopentanoic acid. 4-nitro benzylester Proceed analogously to A d). The resulting mixture of the two isomeric title compounds is separated by chromatography on silica gel (dichloromethane/ether=10/6) and fractional crystallisation.

NMR for 4 (S)-isomer (CDCI3) (keto/enolform=2/1) :

1.23(d,J=7.5,keto) # 3H 1.26 (d, J=7.5Hz, envol) J 1.30 (dd, J=25u. 6, 5Hz, enol) 3H 1.33 (dd, J=25u. 6,5Hz, keto) J 2@50 (quintJ=7t5Hztenol) | 2H 2.95-3.24 (m, keto/enol) J 3.64 (d, J=17, 5Hz, keto) # 1,4H 3.68 (d, J=17,5Hz # 3.83 (dd, J=7. 5u. 2Hz, enol) # 2H 3.97 (dd, J = 6u. 2Hz, keto) 2H 4.34 (dm, 1, J=4/, bHz) 5.18 (s, 0,3H, enol) 5.29 (s, 2) 6.41 (br, 1) 7.54 (d, 2, J=8Hz) 8.25 (d, 2, J=8Hz) 11.95 (s, 0,3H, enol) NMR for 4 (R)-isomer (CDCI3) (keto/enolform=2/1) : 1.26 (d, 3, J=7, 5Hz) 1.50 (dd, 3, J=25u. 7Hz)

2.41 (dq, J = 10u. 7, 5Hz, enol) t 1 H 2.76 (dq. J=10u. 7,5Hz, keto) 2.93 (ddd, J=15, 8u. 2Hz, keto) 3.00(ddd,J=16,3,8u.1.8Hz,enol) # # 3.69(s keto)1.4H 3.69(s,keto)1,4H

3. 72 (dd, J=10u. 1,8Hz, enol 3.75 (dd, J=10u. 2Hz, keto)) 4. SU (dm, 1, J=47, 5Hz) 5.18 (s, 0,3H, enol) 5.29 (s, 2) 6.00 (s, 0,3H, enol)

6.08 (br, enol) 1H 6.16 (br, keto) J 7.55 (d, 2, J=9Hz) 8.25 (d, 2J=9Hz) C) (4R, 5R, 6R)-1-aza-3, 7-dioxo-6-[1 (R)-fluorethylj-4-methylbicyclo [3. 2.0]-heptane-2-carboxylic acid.4-nitrobenzylester a) 4 (RJ [ (3R, 4R)-3- [1 (R)-fluorethyl]-2-oxoazetidine-4-ylj-2-diazo-3-oxopentanoic acid. 4-ni- trobenzylester Proceed analogously to A e), using 4 (R)- [ (3R, 4R)-3- [1 (R)-fluorethyl]-2-oxoazetidine-4-yl]-3- oxopentanoic acid. 4-nitrobenzylester as starting material, to obtain the title compound.

NMR (CDCIs) : 1.20 (d, 3, J=7Hz); 1.46 (dd, 3, J=24+6.5Hz); 3.17 (ddd, 1, J=20, 6.8+2Hz); 3.86-4.00 (m, 2); 4.93 (d of quint. 1, J=48+6. 5Hz); 5.35 (d, 1, J=15Hz); 5.39 (d, 1, J=15Hz); 6.00 (br, 1) ; 7.56 (d, 2, J=8Hz); 8,29 (d, 2, J=8Hz). b) (4R, 5R, 6R)-aza-3, 7-dioxo-6 [1 (R)-fluorethylJ-4-methylbicyclo [3. 2.0]-heptane-2-carboxylic acid.4-nitrobenzylester Proceed analogously to A f), using the compound obtained under C a) as starting material, to obtain the title compound.

NMR (CDCI3) : 1.30 (d, 3, J=8Hz); 1.53 (dd, 3, J=23. 3+6.3Hz); 2.86 (quint., 1, J=8Hz); 3.42 (ddd, 1, J=17. 5,7.5+2Hz); 4.28 (dd, 1, J=8+2Hz) ; 4.76 (s, 1) ; 5.09 (ddq, 1, J=47. 5,7.5+6.3Hz); 5.27 (d, 1, J=12. 5Hz); 5.37 (d, 1, J=12. 5Hz); 7.55 (d, 2, J=8Hz) ; 8.46 (d, 2, J=8Hz).

D) (4S, 5R, 6R)-1-aza-3,7-dioxo-6[1(R)-fluorethyl]-4-methylbicyclo[3. 2.0]-heptane-2-carboxylic acid. 4-nitrobenzylester a) 4 (SJ [ (3R, 4R)-3- (1 (RJ-fluorethylj-2-oxoazetidine-4-ylJ-2-diazo-3-oxopentanoic acid. 4-ni- trobenzylester Proceed analogously to A e), using 4 (S)- [ (3R, 4R)-3- [1 (R)--fluorethyl]-3-oxopentanoic acid. 4nitrobenzylester as starting material, to obtain the title compound.

NMR (CDCI3) : 1.22 (d, 3, J=7. 2Hz) ; 1.49 (dd, 3. J=24. 5+6. 3Hz); 3.01 (ddd, 1, J=16, 7.5+2Hz); 3.56 (dq, 1, J=9+7.2Hz); 3.92 (dd, 1, J=9+2Hz); 4.91 (ddq, 1, J=48.5,7.5+6.3Hz); 5.36 (d, 1, J=13.8Hz); 5.39 (d, 1. J=13.8 Hz), 5.98 (br, 1 ; 7.56 (d, 2, J=9Hz); 8.29 (d, 2, J=9Hz). b) (4S, 5R, 6R) 1-aza-3, 7-dioxo-6l 1 {R)-fluorethyl]-4-methylbicyclo [3. 2. OJ-heptane-2-car- boxylic acid. 4-nitrobenzylester Proceed analogously to A f), using the product obtained under D a) as starting material, to obtain the title compound.

NMR (CDCI3) : 1.30 (d, 3, J=7Hz); 1.54 (dd, 3, J=25+6. 3Hz) ; 2.40 (dq, 1, J=8+7Hz) ; 3.39 (ddd, 1, J=18.7. 5+1. 8Hz); 3.76 (dd, 1, J=8+ 1. 8Hz); 4.84 (s, 1) ; 5.10 (ddq, 1, J=49,7.5+6.3Hz); 5.27 (d, 1, J=12. 5Hz); 5.36 (d, 1, J=12. 5Hz); 7.55 (d, 2, J=9Hz); 8.25 (d, 2, J=9Hz).

Claims (2)

1. A compound of the formula

wherein R, is H or CH3 ; r3 is H or lower alkyl ; R4 is lower alkyl ; Rg is a protecting group or a physiologically-hydrolysable and acceptable ester group; and R, o is a leaving group.

2. A compound of the formula

wherein R,, R3, R4 and Rg are as defined in claim 1.