IL122990A - Taxane derivatives and processes for their preparation - Google Patents

Abstract

Compounds of the formula wherein: R20 is a hydroxy-protecting group or hydrogen, and R is C(O)R10, wherein R10 is hydrogen, alkyl, wherein said alkyl is not methyl; alkenyl, alkynyl, cycloalkyl, cycloalkenyl, -OR16, aryl or heterocyclo, and R16 is alkyl.

Description

TAXANE DERIVATIVES AND PROCESSES FOR THEIR PREPARATION The present invention relates to taxane derivatives and methods for the preparation thereof, which taxane derivatives can be used for the preparation of sidechain-bearing taxanes.

The present application is divided from Israel Specification No. 108,161, filed December 23, 1993. In order that the invention may be better understood and appreciated, description from Israel Specification No. 108,161 is included herein, it being understood that this is for background purposes only, the subject matter of Israel Specification 108,161 being specifically disclaimed and not forming a part of the present invention.

Taxanes are diterpene compounds which find utility in the pharmaceutical field. For example, taxol, a taxane having the structure: where Ph is phenyl, Ac is acetyl and Bz is benzoyl, has been found to be an effective anti-cancer agent. Naturally-occurring taxanes such as taxol may be found in plant materials, and have been isolated therefrom. Such taxanes may, however, be present in plant materials in relatively small amounts, so that, in the case of taxol, for example, large numbers of the slow-growing yew trees forming a source for the compound may be required. The art has thus continued to search for synthetic, including semi-synthetic, routes for the preparation of taxanes such as taxol and analogs thereof. 1A IL 89,831 (equivalent to US 4,924,012) and US 4,924,011, disclose compounds similar to those of the present invention, however the above patents refer only to certain compounds having -OC(0)-CH3 at the C-4 position. There is simply no motivation whatsoever, for a person skilled in art, provided by the above patents to prepare compounds having groups at C-4 other than -0-C(0)-CH3.

Furthermore, the process of the present invention, as denned hereinafter, is directed to a process wherein, inter alia, the C-4 group -0-C(0)-CH3 present in the baccatin ΙΠ starting material is converted to a desired C-4 group. The above patents neither disclose nor suggest any modification at C-4, and thus clearly do not teach or suggest the subject matter of the present invention. 2 In Israel Specification No. 122,208, divided from Israel Specification 108,161, there is described and claimed a novel, overall method for the preparation of novel sidechain-bearing taxanes, comprising the following steps (a) through (e): (a) preparing an oxazoline compound of the tallowing formula I or a salt thereof: wnere R1 is RS, R7-0-, R7-S-. or (R2)(RS)N-; 2 is R7-0-, R7-S-. or (R^ ^N-; R3 and 4 are independently Rs. RS-O-C(O)-, or (Rs)(R6)N-C(OV; Rs and R6 are independently hydrogen, aikyl, alkenyl, alkynyl, cycloalkyl, cycioalkenyf, aryl, or heterocycio; and R7 is aikyl, alkenyl, aikynyl, cycloalkyl, cycioalkenyl, aryl or heterocycio; (b) converting the axazoline of formula I or salt thereof to an oxazoline of the formula II or a salt thereof: 3 .. . R where R1, R3 and R4 are as defined above; (c) coupling the oxazoiine of the formula ll or salt thereof with a taxane having a hydroxy! group directly bonded to C-13 thereof, or salt thereof, to form an oxazoiine sidechain-bearing taxane of the following formula III or a salt thereon R where R\ R3 and R4 are as defined above, and T is a taxane moiety preferably a compound of Formula IX bended directly through C- 3 of said moiety; (d) contacting the oxazoiine sidechain-bearing taxane of the fcrmuia 111 or salt thereof with an aqueous acid capable of opening the oxazoiine ring of said ccmpcund of the formula 111 or salt thereof to form a sidechain-bearing taxane of the following formula X or salt thereof: 4 where R1, R3, R4 and T are as defined above, and the acid salt at the amine group in said formula X is formed by contact with said ring-opening acid; and (e) contacting said sidechain-bearing taxane of the formula X or salt thereof with a base, to form a sidechain-bearing taxane of the following formula IV or salt thereof: . ' where R1, R3, R4 and T are as defined above.

In Israel Specification 108,161, in the present specification, and in further specifications divided from Israel Specification 108,161, there are described and claimed the individual methods of each of steps (a) through (e) which are novel methods, and the novel compounds of the formulae I, Π, HI, IV, IX and X, and salts and hydrates thereof, as described herein. Also included are novel prodrugs of these compounds.

According to the invention of the present specification, there is now provided a taxane compound of the following formula XIV: OBz wherein: R20 is a hydroxy-protecting group or hydrogen, and R is C(0)R10, wherein R10 is hydrogen, alkyl, wherein said alkyl is not methyl; alkenyl, alkynyl, cycloalkyl, cycloalkenyl, -OR16, aryl or heterocyclo, and R16 is alkyl. 4A The present invention also provides a process to produce a compound of the formula: wherein: R20 is a hydroxy-protecting group or hydrogen, and R is C(0)R10, wherein R10 is hydrogen, alkyl, wherein said alkyl is not methyl; alkenyl, alkynyL, cycloalkyl, cycloalkenyl, -OR16, aryl or heterocyclo, and R16 is alkyl. which process comprises: a) reacting Baccatin HI with a suitable agent in excess to protect the hydroxy groups at C-7 and C-13 in an inert organic solvent, at from about -30°C to room temperature; b) reacting the product of (a) with a trimethylsilane or dimethylsilane in the presence of a tertiary amine base, at from about -30°C to room temperature; c) reducing the product of (b) by reaction with red-Al or lithium aluminium hydride at from about -30°C to 0°C; d) reacting the product of (c) with an acyl chloride, acid anhydride or mixed anhydride in the presence of an alkali metal anion of a secondary amine base, at from about -30°C to room temperature; e) deprotecting the product of (d) by reaction with pyridinium fluoride in acetonitrile, followed by tetrabutyiammonium fluoride or casium fluoride in THF, and optionally, f) reacting the product of (e) with a suitable agent to effect protection of the hydroxy group at C-7. 4B The present invention is described further, as follows: In the present specification, the terms 'alkyl' or 'alk,' as used herein alone or as part of another group, denote optionally substituted, straight and branched chain saturated hydrocarbon groups, preferably having 1 to 10 carbons in the normal chain, most preferably lower alkyl groups. Exemplary unsubstituted such groups include methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, isobutyl, pentyl, hexyl, isohexyl, heptyl, 4,4-dimethylpentyl, octyl, 2,2,4-trimethylpentyl, nonyl, decyl, undecyl, dodecyl and the like. Exemplary substituents may include one or more of the following groups: halo, alkoxy, alkylthio, alkenyl, alkynyl, aryl (e.g., to form a benzyl group), cycloalkyl, cycloalkenyl, hydroxy or protected 5 hydroxy, carboxyl (-COOH), alkyloxycarbonyl, alkyicarbonyloxy, alkylcarbonyl, carbamoyl (NH2-CO-), substituted carbamoyl ((R5)(R6)N-CO- where R5 or R6 are as defined above, except that at least one of R5 or R6 is not hydrogen), amino (-NH2), heterocyclo, mono- or dialkylamino, or thiol (-SH).

The terms "lower alk" or "lower alkyl" as used herein, denote such optionally substituted groups as described above for alkyl having 1 to 4 carbon atoms in the normal chain.

The terms "alkoxy" or "alkylthio" denote an alkyl group as described above bonded through an oxygen linkage (-0-) or a sulfur linkage (-S-), respectively. The term "alkyloxycarbonyl", as used herein, denotes an alkoxy group bonded through a carbonyl group. The term "alkylcarbonyl". as used herein, denotes an alkyl group bonded through a carbonyl group. The term "alkyicarbonyloxy", as used herein, denotes an alkyl group bonded through a carbonyl group which is, in turn, bonded through an oxygen linkage. The terms "monoalkylamino" or "dialkylamino" denote an amino group substituted by one or two alkyl groups as described above, respectively.

The term "alkenyl", as used herein alone or as part of another group, denotes optionally substituted, straight and branched chain hydrocarbon groups containing at least one carbon to carbon double bond in the chain, and preferably having 2 to 10 carbons in the normal chain. Exemplary unsubstituted such groups include ethenyl, propenyl, isobutenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, and the like. Exemplary substituents may include one or more of the following groups: halo, alkoxy, alkylthio, alkyl, alkynyl, aryl, cycloalkyl, cycloalkenyl, hydroxy or protected hydroxy, carboxyl (-COOH), alkyloxycarbonyl, alkyicarbonyloxy, alkylcarbonyl, carbamoyl (NH2-CO-), substituted carbamoyl ((R5)(R6)N-CO- where R5 or R6 are as defined above, except that at least one of Rs or R6 is not hydrogen), amino (-NH2), heterocyclo, mono- or dialkylamino, or thiol (-SH). 6 The term "alkynyl", as used herein alone or as part of another group, denotes optionally substituted, straight and branched chain hydrocarbon groups containing at least one carbon to carbon triple bond in the chain, and preferably having 2 to 10 carbons in the normal chain. Exemplary unsubstituted such groups include ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, decynyl, and the like.

Exemplary substituents may include one or more of the following groups: halo, alkoxy, alkylthio, alkyl, alkenyl, aryl, cycloalkyl, cycloalkenyl, hydroxy or protected hydroxy, carboxyl (-COOH), alkyioxycarbonyl, alkyicarbonyloxy, alkylcarbonyl, carbamoyl (NH2-CO-), substituted carbamoyl ((Rs)(R6)N-CO- where R5 or R6 are as defined above, except that at least one of R5 or R6 is not hydrogen), amino (-NH2), heterocyclo, mono- or dialkylamino, or thiol (-SH).

The term "cycloalkyl", as used herein alone or as part of another group, denotes optionally substituted, saturated cyclic hydrocarbon ring systems, preferably containing 1 to 3 rings and 3 to 7 carbons per ring. Exemplary unsubstituted such groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, cyclododecyl, and adamantyl. Exemplary substituents include one or more alkyl groups as described above, or one or more groups described above as alkyl substituents.

The term "cycloalkeny , as used herein alone or as part of another group, denotes such optionally substituted groups as described above for cycloalkyl, further containing at least one carbon to carbon double bond forming a partially unsaturated ring.

The terms "ar" or "aryl", as used herein alone or as part of another group, denote optionally substituted, homocyclic aromatic groups, preferably containing 1 or 2 rings and 6 to 12 ring carbons.

Exemplary unsubstituted such groups include phenyl, biphenyl, and naphthyl. Exemplary substituents include one or more, preferably three or fewer, nitro groups, alkyl groups as described above or groups described above as alkyl substituents. 7 The terms "heterocycio" or "heterocyclic", as used herein alone or as part of another group, denote optionally substituted fully saturated or unsaturated, aromatic or non-aromatic cyclic groups having at least one heteroatom in at least one ring, preferably monocyclic or bicyclic groups having 5 or 6 atoms in each ring. The heterocycio group may, for example, have 1 or 2 oxygen atoms, 1 or 2 sulfur atoms, and/or 1 to 4 nitrogen atoms in the ring. Each heterocycio group may be bonded through any carbon or heteroatom of the ring system. Exemplary heterocycio groups include the following: thienyl, furyl, pyrrolyl, pyridyl, imidazolyl, pyrrolidinyl, piperidinyl, azepinyl, indolyl, isoindolyl, quinolinyl, isoquinolinyl, benzothiazolyl, benzoxazolyl, benzimidazolyl, benzoxadiazolyl, and benzofurazanyl. Exemplary substituents include one or more alkyl groups as described above or one or more groups described above as alkyl substituents. Also incl uded are smaller heterocyclos , such as, epoxides and azi r dines .

The terms "halogen", "halo", or "haP, as used herein alone or as part of another group, denote chlorine, bromine, fluorine, and iodine.

The term "taxane moiety", as used herein, denotes moieties containing the core structure: which core structure may be substituted and which may contain ethylenic unsaturation in the ring system thereof.

The term "taxane", as used herein, denotes compounds containing a taxane moiety as described above.

The term "hydroxy (or hydroxyl) protecting group", as used herein, denotes any group capable of protecting a free hydroxyl group which, subsequent to the reaction for which it is employed, may be 8 removed without destroying the remainder of the molecule. Such groups, and the synthesis thereof, may be found in Protective Groups in Organic Synthesis by T.w. Greene, John Wiley and Sons (1991) or Fieser & Fieser. Exemplary hydroxyl-protecting groups include methoxymethyl, 1-ethoxyethyl, 1-methoxy-l-methylethyl, benzyloxymethyl, ( -trimethylsilyletiioxy)methyl, tetrahydropyranyl, 2,2,2-tri-chloroethoxycarbonyl, t-butyl(diphenyl)silyl, trialkylsilyl, trichloromethoxy-carbonyl, and 2,2,2-trichloroethoxymethyl.

The term "salt" includes acidic and/or basic salts formed with inorganic and/or organic acids and bases. Exemplary acidic salts include salts formed with mineral acids, such as HC1, H2SO4 or HNO3, or carboxylic acids such as trifluoroacetic acid or acetic acid. Exemplary basic salts include salts formed with amines, such as trietiiylamine, diisopropylemylamine or pyridine, or amino acids such as arginine or guanidine. Salts of hydroxyl groups, such as metal (e.g., alkali or alkaline earth metal) alkoxides, are also contemplated as "salts" herein. Metal alkoxide salts may, for example, be formed by contacting a hydroxyl group with a metallating agent.

Reference to a compound employed in or prepared by the methods of the present invention includes salts and hydrates thereof.

Israel Specification 121,539 provides novel methods for the preparation of oxazoline compounds of the formula I and salts thereof, and in particular, the dehydration, displacement and exchange methods described below.

Said Specification also provides novel oxazoline compounds of the formula I and salts thereof, including all stereoisomers thereof, either substantially free of other stereoisomers, or in admixture with other selected, or all other stereoisomers, with the provisos that, when R1 is phenyl and one of R3 or R4 is hydrogen, (i) R2 is not methoxy when the other of R3 or R4 is pentadecyi, benzyl, or methoxycarbonyl, or (ii) R2 is not ethoxy when the other of R3 or R4 is ethoxycarbonyi; when R1 is methyl and one of R3 or R4 is hydrogen, R2 is not 8-phenylmenthyloxy when the other of R3 or R4 is 2-methylpropyl; and when R1 is acetylmethyl and R3 and R4 are hydrogen, R2 is not ethoxy or NH2.

Oxazolines of the formula la and salts thereof described following are preferred, especially compounds of the formula la having those substituents set forth in the section below entitled "Preferred Compounds".

Dehydration Method Oxazoline compounds of the formula I or salts thereof may be prepared by a dehydration method, comprising the step of contacting a compound of the following formula V or a salt thereof: R'-C(0)-NH where R1, R2 R3 and R4 are as defined above, with an acid capable of effecting dehydration of the compound of formula V or salt thereof to form a compound of the formula I or salt thereof.

The starting compounds of the formula V and salts thereof may be prepared by procedures such as those described in U.S. Patent o. 5,420,337; Ojima et al., J. Org. Chem., 56, 1681 - 1683 (1991); Georg et al Tetrahedron Lett., 32, 3151 - 3154 (1991); Denis et al., J. Org. Chem., 51 , 46 - 50 (1986); Corey et al.. Tetrahedron Lett., 32, 2857 - 2860 (1991); Deng et al., J. Org. Chem., 57, 4320 - 4323 (1992); Ojima et al., 10 Tetrahedron, 48, 6985 - 7012 (1992); Commercon et al., Tett. Lett., 33, 5185 - 5188 (1992); Denis et al.,' J. Org. Chem., 56(24), 6939-6942 (1991 ) (for example, followed by esterification and treatment with acid); and Denis et al., J. Org. Chem., 55, 1957 - 1959 (1990), all incorporated herein by reference.

Any acid capable of effecting dehydration may be employed in the dehydration method of the present invention. Exemplary acids include sulfonic acids such as pyridinium p-toluene sulfonic acid, p-toluene sulfonic acid, camphorsulfonic acid, and methane sulfonic acid, carboxyiic acids such as trifluoroacetic acid or acetic acid, or mineral acids such as HCI, H2S04 or HNO3. Mole ratios of acid: compound of formula V are preferably from about 1 :100 to about 1 :1.

The reaction is preferably conducted at a temperature of from about 0°C to about 200°C, and at a pressure of about 1 atm to about 5 atm. The reaction is preferably conducted under an atmosphere of inert gas such as argon.

Solvents are preferably employed which are inert, organic solvents such as toluene, tetrahydrofuran, acetonitrile, benzene or xylene. The amount of solvent employed preferably provides a loading of the starting compound of formula V of about 2.5% by weight, based on the combined weight of solvent and formula V compound.

The oxazoline ring of the compounds of the formula I is numbered herein as follows: 2 With respect to the 4- and 5-position carbon atoms, the oxazoline compounds of the formula I may exist as four stereoisomers la, lb, lc and Id as follows: 1 1 The compounds of the formula V may also exist as four stereoisomers, with respect to the carbon atoms at the corresponding positions. These stereoisomers are the following compounds Va, Vb, Vc and Vd: 12 A desired stereoisomer of the compound of the formula I may, for example, be prepared by the present dehydration method by employing the appropriate stereoisomer of the starting compound of the formula V. Thus, use of a compound Va will provide a compound la, use of a compound Vb will provide a compound Id, use of a compound Vc will provide a compound lc, and use of a compound Vd will provide a compound lb. It is preferred to employ a single stereoisomer of the starting compound V in the present dehydration method, although stereoisomeric mixtures may also be employed. Use of a compound Va to prepare a compound la, especially to prepare a compound la having those substituents set forth in the section below entitled "Preferred Compounds", is particularly preferred.

Displacement Method Oxazoline compounds of the formula I or salts thereof may also be prepared by a displacement method, comprising the step of contacting a compound of the formula V or salt thereof, in the presence of a base, with an activating agent capable of activating the hydroxyl group of the compound of the formula V or salt thereof to allow intramolecular displacement and formation of a compound of the formula I or salt thereof, with the proviso that, when R1 is phenyl, and one of R3 or R4 is hydrogen, (i) R2 is not ethoxy when the other of R3 or R4 is ethoxycarbonyl, or (ii) R2 is not methoxy when the other of R3 or R4 is benzyl.

Any compound capable of activating the hydroxyl group of the compound of the formula V and effecting intramolecular displacement may be employed as the activating agent in the displacement method of the present invention. Exemplary activating agents include suifonyl haiides such as alkyl suifonyl haiides (e.g., methyl suifonyl chloride), or aryl suifonyl haiides (e.g., benzene suifonyl chloride or p-toluenesulfonyl chloride), phosphorus oxychloride (POCI3), phosphorus pentachloride (PCI5), or thionyl chloride (SOCI2). Mole ratios of activating agent: compound of formula V are preferably from about 1 :1 to about 2:1.

Activation of the hydroxyl group of a compound of the formula V or salt thereof may produce a novel intermediate compound of the formula VI or salt thereof: where R , R2, R3 and R4 are as defined above, and L is a leaving group such as alkyl sulfonyloxy (e.g., methyl sulfonyloxy), aryl sulfonyloxy (e.g., benzene sulfonyloxy or p-toluenesulfonyloxy), chloro, or a phosphorus oxy group (P02- or PO-). The present invention provides the 14 aforementioned novei compounds of the formula VI and salts thereof, including all stereoisomers thereof, either substantially free of other stereoisomers, or in admixture with other selected, or all other stereoisomers, with the proviso that, when R1 is phenyl, R2 is methoxy and one of R3 or R4 is hydrogen and the other benzyl, L is not chloro.

Bases which may be employed include organic bases such as amines (e.g., pyridine, triethylamine, diisopropylethylamine, lutidine, or 1 ,8-diazabicyclo[5.4.0]undec-7-ene), or lithium hexamethyl disilazide, or inorganic bases such as alkali metal carbonates (e.g., potassium carbonate). Mole ratios of base: compound of formula V are preferably greater than about 2:1.

The reaction is preferably conducted at a temperature of from about -20°C to about 100°C. particularly 0°C, and at a pressure of about 1 atm. The reaction is preferably conducted under an atmosphere of inert gas such as argon.

Solvents are preferably employed which are inert organic solvents such as chloroform, methylene chloride, toluene, tetrahydrofuran, acetonitriie or, most preferably, which are basic organic solvents capable of functioning both as solvent and as base for the present method such as pyridine, triethylamine, or lutidine. The amount of solvent employed preferably provides a loading of the starting compound of the formula V of about 10% by weight, based on the combined weight of solvent and formula V compound.

A desired stereoisomer of the compound of the formula I may, for example, be prepared by the present displacement method by employing the appropriate stereoisomer of the starting compound of the formula V. Thus, use of a compound Va will provide a compound Ic, use of a compound Vb will provide a compound lb, use of a compound Vc will provide a compound la, and use of a compound Vd will provide a compound Id. It is preferred to employ a single stereoisomer of the starting compound V in the present displacement method, although 15 stereoisomeric mixtures may also be employed. Use of a compound Vc to form a compound la, especially to prepare a compound la having those substituents set forth in the section below entitled "Preferred Compounds", is particularly preferred.

Exchange Method Oxazoline compounds of the formula I where R1 is R ' as defined following or salts thereof may also be prepared by an exchange method, comprising the step of contacting a compound of the following formula VII or a salt thereof: where R2, R3 and R4 are as defined above, with a compound of the following formula VIII or salt thereof: where R1' and E are independently alkyl, alkenyi, alkynyl, cycloalkyl, cycloalkenyl, aryl or heterocyclo; with the provisos that, when E is ethyl, one of R3 or R4 is hydrogen, and (i) R1' is phenyl, R2 is not methoxy when the other of R3 or R4 is methoxycarbonyl, and R2 is not ethoxy when the other of R3 or R4 is ethoxycarbonyl; and (ii) R1 ' is methyl, R2 is not 8-phenylmenthyloxy when the other of R3 or R4 is 2-methylpropyl.

When both starting compounds VII and VIII are simultaneously employed as acid salts at the NH2 and HN groups, respectively, an amine base, such as ammonia or an organic amine base, may be employed to form a free NH2 and/or HN group, respectively, to allow the reaction to proceed efficiently. Any amine base capable of forming the 1 6 free NH2 and/or HN group(s) may be employed therein. Tertiary amine bases such as triethylamine, diisopropylethylamine, lutidine, pyridine or 1 ,8-diazabicyclo[5.4.0]undec-7-ene are preferred. Mole ratios of amine base: compound of formula VII are preferably from about 1 :1 to about 10:1.

The starting compounds of the formula VII and salts thereof may be prepared by methods such as those described in U.S. Patent Application Serial No. 07/975,453, filed November 12, 1992 by Patel et al.; Commercon et al., Tetrahedron Lett., 33 (36), 5185 - 5188 (1992); Corey et al., Tetrahedron Lett., 32, 2857 - 2860 (1991 ); Ojima et al., Tetrahedron, 48, 6985 - 7012 (1992); and Ojima et al., Tetrahedron Lett., 33, 5737 - 5740 ( 992), all incorporated herein by reference. The starting compounds of the formula VIII and salts thereof may be prepared by methods such as those described in Kimball et al.. Org. Synth. Coll. Vol. II, p. 284 (1943). Use of acidic salts of compounds of the formula VIII, for example, salts formed with carboxylic, sulfonic or mineral acids, are preferably employed as starting materials, as such compounds are relatively stable and easily handled. The aforementioned salts may be neutralized upon contact with the base employed as discussed above. Mole ratios of compound of formula VIII: compound of formula VII are preferably from about 1 :1 to about 2:1.

The reaction is preferably conducted at a temperature of from about 0°C to about 100°C, and at a pressure of about 1 atm. The ■ reaction is preferably conducted under an inert atmosphere, such as argon or nitrogen.

Solvents are preferably employed which are inert organic solvents such as toluene, tetrahydrofuran, dichloromethane, 1 ,2-dichloroethane, or chloroform. The amount of solvent employed preferably provides a loading of the starting compound of the formula VII of about 6% by weight, based on the combined weight of solvent and formula VII compound. 1 7 The compounds of the formula VII may, as with the compounds of the formula V, exist as four stereoisomers with respect to the carbon atoms at the corresponding positions. These stereoisomers are the following compounds Vila, Vllb, Vllc and Vlld: A desired stereoisomer of the compound of the formula I may, for example, be prepared by the present exchange method by employing the appropriate stereoisomer of the starting compound of the formula VII. Thus, use of a compound Vila will provide a compound la, use of a compound Vllb will provide a compound Id, use of a compound Vllc will provide a compound Ic, and use of a compound Vlld will provide 18 a compound lb. It is preferred to employ a single stereoisomer of the starting compound VII in the present exchange method, although stereoisomeric mixtures may also be employed. Use of a compound Vila to prepare a compound la, especially to prepare a compound la having those substituents set forth in the section below entitled "Preferred Compounds", is particularly preferred.

Preparation of Oxazoline Compounds of the Formula II and Salts Thereof Oxazoline compounds of the formula II and salts thereof may be prepared from oxazoline compounds of the formula I and salts thereof by converting the group -C(0)-R2 to the group -C(0)-OH.

Any agent capable of the aforementioned conversion may be employed. For example, when R2 is alkoxy such as methoxy or ethoxy, the compound of the formula I or salt thereof may be dealkylated to form a compound of the formula II by use of a suitable nucleophilic agent, such as the alkali or alkaline earth metal salts of methanethiol.

Alternatively, hydrogenation may be employed, for example, to convert groups such as benzyloxycarbonyl to carboxyl, by use of a hydrogenating agent, for example, hydrogen and a hydrogenation catalyst such as palladium.

Preferably, conversion of the group -C(0)-R2 to a carboxyl group is conducted by hydrolysis. Any compound capable of effecting hydrolysis may be employed as the hydrolysis agent therein. Exemplary hydrolysis agents include aqueous bases such as hydroxides (e.g., metal hydroxides such as barium hydroxide, or preferably, alkali metal hydroxides such as lithium, sodium or potassium hydroxide). Mole ratios of base: compound of formula I are preferably from about 1 :1 to about 3: . Mole ratios of water: compound of formula I are preferably from about 1 :1 to about 100:1.

The reaction is preferably conducted at a temperature of from about -20°C to about 100°C, and at a pressure of about 1 atm. Hydroxide saponification of compounds of the formula I or salts thereof, where R2 is -N(R5)(R6), is preferably conducted in the higher temperatures of the aforementioned temperature range, or at temperatures approaching or at the reflux temperature of the liquid medium employed. The reaction is preferably conducted under an atmosphere of nitrogen, argon or air.

Solvents may be selected from inorganic and organic liquids such as water, alcohols, toluene, tetrahydrofuran, dioxane, acetonitrile, or dimethylformamide, or mixtures thereof. A mixture of water and an organic liquid such as tetrahydrofuran is preferably employed as solvent. The amount of solvent employed preferably provides a loading of the starting compound of the formula I of about 7% by weight, based on the combined weight of solvent and formula I compound.

Israel Specification No. 121,541, divided from the Israel Specification No. 108,161, provides the novel compounds of the formula II and salts thereof, including all stereoisomers thereof, either substantially free of other stereoisomers, or in admixture with other selected, or all other, stereoisomers, with the proviso that when R1 is phenyl and one of R3 or R4 is hydrogen, the other of R3 or R4 is not COOH. As with the oxazolines of the formula I, the oxazolines of the formula II may exist as four stereoisomers with respect to the 4- and 5-position carbon atoms. These stereoisomers are the following compounds Ha, lib, lie and lid: 20 R' Oxazolines of the formula lla and salts thereof are preferred, especially compounds of the formula lla having those substituents set forth in the section below entitled "Preferred Compounds".

The stereoconfiguration of the starting compound of the formula I or salt thereof may be retained and/or inverted in the present method. Thus, for example, hydrolysis of a compound of the formula I having 21 substituents which are in the cis. position relative to each other at the 4-and 5-positions may be hydrolyzed to provide a compound of the formula II having the corresponding cis configuration, a compound of the formula II having the corresponding trans configuration where the 5-position carboxyl substituent is inverted relative to the starting compound, or a mixture of the aforementioned cis and trans compounds. Bases which, when employed for hydrolysis, deprotonate the carbon atom through which the group -C(0)-R2 is bonded, and which subsequently reprotonate the aforementioned carbon from the opposite face of the ring system, result in inversion of the stereoconfiguration. Exemplary such bases include those described above or alkali metal carbonates such as potassium carbonate, amine bases, or metal, such as alkali or alkaline earth metal, alkoxides,. the latter which may be formed prior to addition thereof or in situ (for example, by addition of a metallating agent such as n-butyllithium together with an aikanol such as ethanol).

Where the stereoconfiguration is inverted during the present method as described above, a compound of the formula I having an inverted stereoconfiguration relative to the starting compound of the formula I may be formed as an intermediate (i.e., epimerization). Thus, for example, where the starting compound of the formula I has substituents at the 4- and 5-positions which are in the cis position relative to each other, the corresponding trans compound of the formula I where the 5-position substituent -C(0)-R2 is inverted relative to the starting compound may be formed as in intermediate during the hydrolysis reaction. The aforementioned inversion method is also contemplated within the scope of the present invention. - 22 - Coupling to Prepare Oxazoline Sidechain-bearing Taxanes of the Formula III and Salts Thereof A sidechain-bearing taxane of the formula III or a salt thereof may be prepared by a method comprising the step of contacting an oxazoline compound of the formula II or a salt thereof, with a taxane having a hydroxyl group directly bonded to C-13 thereof, or a salt thereof, in the presence of a coupling agent. It is preferred to employ oxazolines of the formula lla or salts thereof in the present method, especially compounds of the formula lla having those substituents set forth in the section below entitled "Preferred Compounds".

Taxanes are compounds containing the core structure: which core structure may be substituted and which may contain ethyienic unsaturation in the ring system thereof, as described above. Any taxane containing a hydroxyl group directly bonded to C-13 thereof, or salt thereof (such as a metal alkoxide salt at the C-13 hydroxyl group) may be employed in the present method. The taxane starting material employed in the method of the present invention may be a compound such as those described in European Patent Publication No. 400,971, incorporated herein by reference, or may be a compound containing a taxane moiety described in, and prepared by procedures described in or analgous to those set forth in U.S. Patent No.5,254,580, by Chen et al., U.S. Patent No. 5,272,171 , by Ueda et al., both incorporated herein by ince. Exemplary such taxanes include those of the following formula IX:: 23 where R8 is hydrogen, hydroxyl, R14-0-, R15-C(0)-0-. or 5 Ri5-0-C(0)-0-; R9 is hydrogen, hydroxyl, fluoro, R14-0-, Ri5-C(0)-0- or Ri5-0-C(0)-0-; R10 and R1 1 are independently hydrogen, alkyl, alkenyl, alkynyl, cycloalkyi, cycloalkenyl, R16-0-, aryl, or heterocyclic) R14 is a hydroxyl protecting group; and R15 is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyi, cycloalkenyl, aryl or heterocyclo.

R16 is alkyl or salts thereof. 15 All stereoconfigurations of the unspecified chiral centers of the compound of the formula IX are contemplated for use in the coupling method of the present invention. The use of a single stereoisomer is preferred, although mixtures thereof may be employed. 7-Trialkylsilyl 20 baccatin III compounds are one of the compounds preferably employed as the starting material of formula IX, most preferably, 7-trimethylsilyl baccatin III or 7-triethylsiiyl baccatin III.

Another series of compounds which are preferable starting 25 materials of formula IX are compounds wherein R8 is OC(0)CH3; R9 is hydroxyl or a hydroxyl protecting group e.g. O-trimethylsilyl or O- triethylsilyl; R10 is as above except melting and R11 is aryl e.g. benzyl.

The latter compounds are considered novel along with methods for their 24 preparation which are set forth below. Especially preferred of the above compounds are those wherein R10 is cycloalkyl or OR16.

The above compounds are prepared by the following general reaction scheme Baccatin Step H wherein R^° is hydrogen wherein R is C(0)R10 and or R14 and R is as above R14 and X are as above Step F Baccatin III is protected at the C-7 and C-13 sites by reaction with a suitable agent, such as, a halotrialkylsilane e.g. trimethyl or triethyl, 2,2,2-trichloroethyl chloroformate or carbobenzyloxy. Any inert organic solvent wherein Baccatin III is soluble may be utilized, such as, THF, DMF, MeCl2 and dioxane. The r-eaction is carried out in the presence of a tertiary amine base, such as, pyridine or imidazole. The reaction temperature can vary from -30"C to room temperature with C-7 substitution occuring preferably at -30*C to O'C and C-13 at 0"C to room 25 temperature. The protecting group reactant concentration is preferably in molar excess (1 -10) to effect both C-7 and C-13 substitution. 5 The intermediate XI is thereafter protected at the C-1 hydroxy by reaction with a trimethylsilane or preferably a dimethylsilane e.g. chlorotrimethylsilane or preferably chlorodimethylsiiane in, for example, D F, THF, dioxane or various ethers. As in step F the reaction is preferably carried out in the presence of a tertiary amine base, such as imidazole or pyridine. The temperature can range from -30"C to room temperature with about O'C as preferred.

Step H I 5 (A) Intermediate XII is thereafter reduced at C-4 to hydroxy by reaction with a suitable reducing agent such as Red-AI or lithium aluminum hydride. The reducing agent is usually present in molar excess (1 -5 equivalents). The reaction solvent can be THF, dioxane or 20 various suitable ethers and the reaction temperature can range from -30*C to O'C with about O'C as preferred.

(B) Intermediate XIII of (A) wherein C-4 is hydroxy is converted to the appropriate C-4 substituent by reaction with the appropriate acyl 25 chloride acid anhydride or mixed anhydride e.g. acryloyl chloride, benzoyl chloride, cycloaikylcarbonyl chloride, alkyl chloroformate, in the presence of an alkali metal (Li, Na or K) anion of a secondary amine base. The reaction solvents include THF, dioxane, etc. The temperature range can be from -30'C to room temperature with about O'C as ) preferred. 2 6 Step 1 (A) The intermediate ΧΠΙ of Step H(B) is thereafter deprotected by reaction with pyridinium fluoride (aqueous hydrogen fluoride in pyridine) in acetonitrile, followed by tetrabutylammonium fluoride in THF or cesium fluoride in THF. Thereafter, the mixture is diluted in an alcohol, washed with mild organic or inorganic acid, and isolated.

(B) Thereafter, the C-7 hydroxy-protecting group may be introduced in XTV as in Step F, following reaction parameters favoring C-7 substitution above.

Subsequently, the appropriate side chain may be introduced at C-13 following the novel process disclosed herein, or alternatively, via Holton methodology, as disclosed in U.S. Patents Nos. 5,227,400; 5,175,315 and 5,229,526, which are incorporated herein by reference.

Israel Specification No. 122,208, divided from Israel Specification 108,161, describes and claims novel end products of the present invention, which are compounds of the formula: R'-QQ-NE 0 wherein: R1 is R5, R7-0-. R7-S-, or (R5)(R6)N-; R3 and R4 are independently R5, R5-0-C(0)-, or (R5)(R6)N-C(0)-; R5 and R6 are independently hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or heterocyclo; and R7 is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or heterocyclo; and T is 27 where R8 is hydrogen, hydroxy!, R14-0-, R 5-C-(0)-0-, or R15-0-C(0)-O-; R9 is hydrogen, hydroxyl, fluoro, R14-0-, R15-C(0)-0- or Ri5-0-C(0)-0-; R10 and R11 are independently hydrogen, alkyl, alkenyl, alkynyl, cycioalkyi, cycloalkenyl, R 6-0-aryl, or heterocyclo; R14 is a hydroxyl protecting group; and R15 is hydrogen, alkyl, alkenyl, alkynyl, cycioalkyi, cycloalkenyl, aryl or heterocyclo, R 6 is alkyl with the proviso that R10 is not methyl or salts or hydrates thereof.

Preferred Compounds Especially preferred among the novel compounds of formula IV are those compounds wherein R10 is cycioalkyi or OR16. Most preferred among the novel compound of formula IV are compounds wherein R10 is cycioalkyi, R1 is aryl, preferably phenyl, or alkoxy preferably t-butyloxy; R3 is aryl, preferably phenyl, heterocyclo preferably 2- or 3-furanyl or thienyl, isobutenyl, 2-propenyl, isopropyl or (CH3)2CH-; R4 is hydrogen; R8 is preferably hydroxyl or alkylcarbonyloxy, e.g. acetyloxy; R9 is hydroxy and R11 is aryl, preferably phenyl.

Any compound capable of effecting esterification of the C-13 hydroxyl group, or salt thereof, of the starting taxane through the carboxyl group of the oxazoline of the formula II or salt thereof may be 28 employed as the coupling agent of the present method. Exemplary coupling agents include those compounds forming an activated oxazoline ester (for example, 1-hydroxybenzotriazole or N-hydroxysuccinimide) or anhydride (for example, an acid chloride such as pivaioyl chloride or bis(2-oxo-3-oxazolidinyl)-phosphinic chloride) when contacted with the oxazoline of the formula II, particularly coupling agents comprising a compound such as a carbodiimide (e.g., dicyclohexylcarbodiimide (DCC), 1 ,3-diisopropylcarbodiimide (DIC), or 1 -(3-dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride), bis(2-oxo-3-oxazolidinyi)phosphinic chloride), carbonyl diimidazole (CDI), pivaioyl chloride, or 2,4,6-trichlorobenzoyl chloride; wherein the aforementioned compounds are preferably employed together with a compound such as 1-hydroxybenzotriazole (HOBt) or N-hydroxysuccinimide (HO-Su), or an amine such as triethylamine, pyridine or pyridine substituted at the 4-position with - iR^XR-17), where R16 and R17 are independently selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl or heterocyclo (to form a compound such as dimethylaminopyridine (DMAP)), or where R16 and R17, together with the nitrogen atom to which they are bonded, form a heterocyclo group (to form a compound such as 4-morpholinopyridine or 4-pyrrolidinopyridine). Mole ratios of coupling agent: starting taxane are preferably from about 1:1 to about 2:1. Mole ratios of oxazoline of the formula II: starting taxane are preferably from about 1 :1 to about 2:1.

The reaction is preferably conducted at a temperature of from about 0°C to about 140°C, and at a pressure of about 1 atm. The reaction is preferably conducted under an atmosphere of inert gas such as argon.

Solvents are preferably employed which are inert organic liquids such as toluene, acetonitrile, 1 ,2-dichloroethane, chloroform, tetrahydrofuran, pyridine, methylene chloride or dimethylformamide. The amount of solvent employed preferably provides a loading of the starting taxane of about 20% by weight, based on the combined weight of solvent and taxane compound. 29 The stereoconfiguration of the substituents at the 4- and 5-positions of the starting oxazoline may be retained and/or inverted in the coupled formula III product, for example, epimerization from cis to trans where the 5-position substituent has been inverted relative to the starting material is contemplated.

The present invention also provides the novel oxazoline sidechain-bearing taxanes of the formula III and salts thereof, including all stereoisomers thereof, either substantially free of other stereoisomers, or in admixture with other selected, or all other stereoisomers.

Ring Opening to Form Taxanes of the Formula X and Salts Thereof A sidechain-bearing taxane of the formula X or a salt thereof may be prepared from an oxazoline sidechain-bearing taxane of the formula III or a salt thereof, by a method comprising the step of contacting a taxane of the formula III or salt thereof with an aqueous acid capable of opening the ring of the oxazoline group bonded through C-13 of the taxane moiety of said taxane compound to form said compound of the formula X or salt thereof.

Any aqueous acid capable of effecting the aforementioned ring opening may be employed in the method of the present invention.

Exemplary ring opening acids include carboxylic acids, such as acetic acid or trifluoroacetic acid, or preferably, mineral acids such as hydrochloric acid, hydrofluoric acid or sulfuric acid, in water. Mole ratios of ring opening acid: compound of formula III are preferably from about 1 :1 to about 10:1. Mole ratios of water: compound of formula III are preferably from about 1 : 1 to about 100: 1.

The ring opening reaction is preferably conducted at a temperature of from about -20°C to about 40°C, and at a pressure of about 1 atm. The reaction is preferably conducted under an atmosphere of nitrogen, argon or air.

Solvents are preferably employed which are inert organic liquids alone or in admixture with water such as tetrahydrofuran, alcohols (preferably, lower alkanols such as methanol), dioxane, toluene, acetonitrile, or mixtures thereof. The amount of solvent employed preferably provides a loading of the starting compound of the formula III of about 5% by weight, based on the combined weight of solvent and formula 111 compound.

A preferred embodiment of the present invention further comprises the step of deprotecting one or more groups, particularly to free hydroxyl groups, on the taxane moiety to prepare taxanes of the formula X. Deprotection may, for example, be conducted prior or subsequent to, or simultaneously with, the aforementioned ring opening method by use of a deprotection agent. Any compound capable of deprotection may be employed as the deprotection agent. For example, acids such as hydrofluoric acid or aqueous protic acids, or tetra-alkylammonium fluorides such as tetra-n-butylammonium fluoride, may be employed for removal of silyl protecting groups; benzyl protecting groups may be removed by hydrogenation; trichloroethoxycarbonyl protecting groups may be removed by contact with zinc; and acetal or ketal protecting groups may be removed by the use of protic acids or Lewis acids.

A preferred embodiment of the present invention comprises simultaneous ring opening and deprotection of one or more hydroxyl groups on the taxane ring structure, particularly at C-7. A particularly preferred embodiment comprises the step of simultaneous ring opening and deprotection by use of an acid (e.g., a mineral acid such as hydrochloric acid) capable of effecting both reactions. Thus, for example, use of an acid under reaction conditions described above for ring opening may allow simultaneous ring opening and deprotection of 31 acid cieavable hydroxyl protecting groups at C-7 such as trialkylsilyl (e.g. trimethyisiiyl or triethylsilyl).

The present invention also provides the novel intermediates of the formula X and salts thereof formed during ring opening and, optionally, deprotection, including all stereoisomers thereof, either substantially free of other stereoisomers, or in admixture with other selected, or all other stereoisomers.

Contact with Base to Form Taxanes of the Formula IV and Salts Thereof Treatment of a compound of the formula X or salt thereof with a base provides a compound of the formula IV or salt thereof. Any base allowing migration of the acyl group -C(0)-R1 to the amine group -NH2, thereby effecting formation of a compound of the formula IV or salt thereof, may be employed in the method of the present invention.

Exemplary bases include alkali metal bicarbonates such as sodium bicarbonate or potassium bicarbonate. Mole ratios of base: compound of formula X are preferably from about 1:1 to about 5:1.

The reaction is preferably conducted at a temperature of from about -20°C to about 80°C. and at a pressure of 1 atm. The reaction is preferably conducted under an atmosphere of argon, nitrogen or air.

Solvents are preferably employed which are inert organic liquids alone or in admixture with water such as tetrahydrofuran, alcohols (preferably, lower alkanols such as methanol), toluene, acetonitrile, dioxane, or mixtures thereof. The amount of solvent employed preferably provides a loading of the compound of the formula X of from about 1 to about 5% by weight, based on the combined weight of solvent and formula X compound. 32 Deprotection of protected groups may be conducted simultaneously with, or subsequent to use of a base, although deprotection prior to contact with a base, especially simultaneously with ring opening, is preferably employed, as described above.

Separatiqn The products of the methods of the present invention may be isolated and purified, for example, by methods such as extraction, distillation, crystallization, and column chromatography.

Sidechain-bearing Taxane Products The sidechain-bearing taxanes of the formula IV and salts thereof prepared by the methods of the present invention are themselves pharmacologically active, or are compounds which may be converted to pharmacologically active products. Pharmaco-logically active taxanes such as taxol may be used as antitumor agents to treat patients suffering from cancers such as breast, ovarian, colon or lung cancers, melanoma or leukemia. The utility of such sidechain-bearing taxanes has been described, for example, in European Patent Publication No. 400,971 , U.S. Patent No. 4,876.399. U.S. Patent No. 4,857,653, U.S. Patent No. 4,814,470, U.S. Patent No. 4.924.012. U.S. Patent No. 4,924,01 1 , U.S. Patent Application Serial No. 07/907.261 , filed July 1 , 1992 by Chen et al., and U.S. Patent Application Serial No. 07/981 ,151 , filed November 24, 1992 by Ueda et al.. all incorporated herein by reference.

Taxotere. having the structure shown following, or especially taxol, having the structure shown above, are preferably ultimately prepared as the sidechain-bearing taxanes of the formula IV: Solvates, such as hydrates, of reactants or products, may be employed or prepared as appropriate in any of the methods of the present invention.

Israel Specification No. 122,209, divided from Israel Specification No. 108,161, describes and claims the water-soluble prodrug forms of the compounds of Formula IV. Such prodrug forms of the compounds of formula IV are produced by introducing at C-7 or C-10 and/or at the 2'-position of the side chain a phosphonoxy group of the general formula: -OCH2(OCH2)mOP(0)(OH)2 wherein: m is 0 or an integer from 1 to 6, inclusive.

The novel prodrugs have the formula: Rl-C(0)- H 0 wherein: R1 is R5, R7-0-, R7-S-, or (R5)(R6)N-; R3 and R4 are independently R5, R5-0-C(0)-, or (R5)(R6)N-C(0)-; R5 and R6 are independently hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or heterocyclo; R7 is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or heterocyclo; and T is 34 where R8 is hydrogen, hydroxy!. R14-0-. R15-C(0)-0-. R15-0-C(0)-0-, or -OCH2(OCH2)mOP(0)(OH)2 ; RT0 and R11 are independently hydrogen, alkyl, alkenyl, alkynyl, cycloalkyi, cycioalkenyl, R16-0-. aryl or heterocyclo; R20 is hydrogen. -OCH2(OCH2)m OP(0)(OH)2, -OC(0)R21 or -OC(0)OR21 wherein R21 is Ci-C6, alkyl optionally substituted with one to six halogen atoms. C3-C6 cycloalkyi, C2-C6 alkenyl or a radical of the formula wherein D is a bond or C-Ce alkyl and Ra, RG and Rc are independently hydrogen, amino, Ci-Cg mono- or di-alkyiamino, halogen, Ci-Ce alkyl or d-C-6 alkoxy; R14 is a hydroxy protecting group; R16 is alkyl; R30 is hydrogen, hydroxy, fluoro, -OCH2(OCH2)m OP(0)(OH)2 or -OC(0)OR21 wherein R21 is as above.

R15 is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyi, cycioalkenyl, aryl or heterocyclo: m is 0 or an integer from 1 to 6 inclusive with the proviso that at least one of R*. R20 and R3° is -OCH^OCH^m OP(0)(OH)2 and Ri° is not methyl and phosphonxy group base salts thereof.

Preferred compounds of formula IV include those wherein R1° is cydoalkyi or O E or OEt: R1 is aryl, preferably phenyl or alkoxy preferably t-butyloxy; R3 is aryl preferably phenyl or heterocyclo, preferably furyl or thienyl or alkenyl preferably propenyl or rsobutenyi; R is hydrogen; Re is hydroxy or alkylcarbonyloxy, preferably acetyloxy R 1 is aryl preferably phenyl; R20 is -OCH2(OCH2)m OP(0)(OH)2 or -OC(0)OR21 wherein R21 is ethyl or N-propyl; R∞ is -OCH2(OCH2)m OP(0)(OH)2 and m is 0 or 1.

The phosphonoxy group is normally introduced following synthesis of the end products of formula IV following procedures set forth in US Patent No. 5,646, 176,which is incorporated by reference herein.

In arriving at the novel prodrugs above, various novel intermediates are formed following the reaction conditions set forth generally in US Patent No. No. 5,646,176. Compounds of formula IV are as starting materials wherein non-desired hydroxy groups have been blocked. The appropriately protected compound of formula IV wherein reactive hydroxy groups are present either at the 2' or 7 or 10 positions or at multiple positions is first connected to a corresponding methylthiomethyi ether [-OCH2(OCH2)mSCH3]. Thereafter depending on the value of m, the ether may be connected to a protected phosphonooxymethyl ether by a variety of steps as set forth in the above US Patent. The phosphono protecting groups(s) and the hydroxy protecting groups may thereafter be removed by conventional techniques.

The free acid can then be converted to the desired base salt thereafter by conventional techniques involving contacting the free acid with a metal base or with an amine. Suitable metal bases include hydroxides, carbonates and bicarbonates of sodium, potassium, lithium, calcium, barium, magnesium, zinc and aluminum; and suitable amines include triethylamine, ammonia, lysine, arginine, N-memylglucarnine, emanolamine, procaine, bezathine, dibenz lamine, tromethamine (TRIS), chloroprocaine, choline, diethanolamine, triethanolamine and the like. The base salts may be further purified by chromatography, followed by lyophilization or crystallization.

The prodrugs may be administered either orally or parenterally, following the teaching of the above-mentioned U.S. Patent Application No. 08/108,015. The compounds of Formula IV and IV' are novel anti-tumor agents showing in vitro cytotoxicity activity against human colon carcinoma cell lines HCT-116 and HCT-116/VM46 and M109 lung carcinoma.

The present invention is further described by the following examples which are illustrative only, and are in no way intended to limit the scope of the instant claims.

As indicated above, while described, exemplified and illustrated herein, the subject matter of Israel Specification No. 108,161 and divided Israel Specifications 121,539; 121,540; 121,541; 121,542; 122,208 and 122,209 does not constitute a part of the present invention, and is specifically disclaimed.

With specific reference now to the examples in detail, it is stressed that the particulars described are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this context, it is to be noted that only subject matter embraced in the scope of the claims appended hereto, whether in the manner defined in the claims or in a manner similar thereto and involving the main features as defined in the claims, is intended to be included in the scope of the present invention, while subject matter of Israel Specifications 108,161, 121,539; 121,540; 121,541; 121,542; 122,208 and 122,209, although described and exemplified to provide background and better understanding of the invention, is not intended for inclusion as part of the present invention. 37 CT-2262 Preparation of f4S-trans .5-Dihvdro-2.4-dtDhenvl-5-oxazolecarboxvlic acid, ethyl ester (2R,3S)-N-benzoyl-3-phenylisoserine ethyl ester (0.104 g, 0.332 mmoles) was added to an oven-dried 10 ml flask, purged with argon, and suspended in toluene (5.0 ml). Pyridinium p-toluene sulfonic acid (PPTS) (42 mg, 0.167 mmoles) was added. After stirring at room temperature for about 1 hour, the mixture was heated to reflux. A clear homogeneous solution was obtained upon heating. After about 1 hour of heating, the reaction mixture became cloudy. TLC after 16.5 hours of heating showed that the reaction was complete (1 :1 ethyl acetate (EtOAc)-.hexane, PMA (phosphomolybdic acid)/ethanol, ultraviolet (U.V.)).

The reaction mixture was diluted with 10 ml of chloroform, washed with 5 ml of saturated aqueous NaHC03, dried over I^SC , filtered, and concentrated to give 97.8 mg of a yellowish oil (yield = 100%). 1H NMR showed that the trans- oxazoline title product had been obtained with only minor («5%) impurities, none of which were the corresponding cis-oxazoline.

- Example 2 Preparation of r4S-trans)-4.5-Dihydro-2.4-diphenvl-5-oxazolecarbn¾yliQ acid, ethyl ester (2S,3S)-N-benzoyl-3-phenylisoserine ethyl ester (0.100 g, 0.319 mmoles) was added to a flame-dried, argon-purged, 5 ml flask, dissolved in pyridine (1.0 ml), and cooled to 0°C. Methyl sulfonyl chloride (38 mg, 0.335 mmoles) was added dropwise, and the yellowish solution was stirred at 0°C for 1 3/4 hours, and then warmed to room temperature. Thin layer chromatography (TLC) after 1 1/2 hours at room temperature showed the reaction to be complete (1 :1 ethyl acetate:hexane. PMA ethanoi, U.V.).

The heterogeneous mixture was diluted with 5 ml ethyl acetate and washed with 1/3 saturated aqueous CUSO4 (10 ml). The aqueous fraction was extracted with 2 x 5 ml ethyl acetate. The combined organic fractions were washed with 5 ml saturated aqueous NaCI, dried over Na2S04, filtered, and concentrated to yield 0.12 g of a yellowish oil.

The title product was purified by silica gel chromatography (column: 20 mm d x 50 mm I) with 1 :1 ethyl acetate:hexane to give 92.6 mg of a yellowish oil (yield = 98.3%). "Ή NMR and mass spec, showed that the trans-oxazoline title product was obtained. Specific rotations: (c = 0.1. CHCI3), [CX]D = +15.6°, [a]578 = +16.3°, [a]s46 = +18.7°. [a]436 = +33.1 °.

The starting compound (2S,3S)-N-benzoyl-3-phenylisoserine ethyl ester was prepared in a separate experiment as follows: - In a 500 ml flask containing a solution of (4S-cis)-4-,5-dihydro-2,4-diphenyl-5-oxazolecarboxylic acid, ethyl ester (0.79 g, 2.67 mmol) in methanol (MeOH) (57 ml) at 0°C was added 1 N HCI (57 ml) with stirring over a 10 minute period. A precipitate was formed during the HCI addition which dissolved during the addition of tetrahydrofuran (THF). THF (57 ml) was then added to clear the solution, and the resulting mixture was stirred at 0°C for 2 hours and 15 minutes. The pH of the solution was adjusted to 9.0 with saturated NaHC03 (120 ml) and then the mixture was allowed to stir at room temperature for 18 hours. (The reaction was monitored by TLC (silica gel) using 4:6 EtOAc:Hexane as eluent, Rf for the starting material = 0.71 , Rf for the product = 0.42, UV visualization).

The reaction was diluted with EtOAc (200 ml) and the aqueous layer was separated and extracted with EtOAc (100 ml x 1 ). The combined EtOAc solution was then washed with brine (150 ml x 1), dried over Na2S04, filtered and concentrated to give crude (2S,3S)-N-benzoyl-3-phenylisoserine ethyl ester as a solid (0.810 g). It was dissolved in hot MeOH (15 ml) and set aside at room temperature for 30 minutes and then at 4°C for 1 hour. The solid was filtered, washed with cold MeOH (2 ml) and dried in vacuo to give 0.43 g of (2S,3S)-N-benzoyl-3-phenyiisoserine ethyl ester as the first crop. A second crop (0.24 g) was also obtained as above to give a total of 0.67 g (80%) of (2S,3S)-N-benzoyl-3-phenylisoserine ethyl ester. (white solid: mp = 160 -161 °C, [CX]D = -40.3° (c 1 , CHCI3).

Elemental Analysis Ο18Η19ΝΟ4·0.03Η2Ο Calc. Found c 68.86 68.99 H 6.12 6.07 N 4.46 4.60 H20 0.20 0.20 - 62 Preparation of (4S-trans)- and ^4S-cis)-4.5-Dihvdro-2.4-diphenyl-S-oxazolecarboxytic acid. ethvl esters (2S.3S)-N-benzoyl-3-phenylisoserine ethyl ester (66.8 mg, 0.213 mmoles) was added to an oven-dried 10 ml flask, purged with argon, and suspended in toluene (4.0 ml). Pyndinium p-toluene sulfonic acid (49 mg, 0.195 mmoles) was added. The flask was equipped with a Dean-Stark trap (filled with 4 angstrom molecular sieves). The reaction was heated to reflux (most of the solids dissolved upon heating). TLC at 5 hours showed that the reaction was nearly complete (1 :1 BOAc:hexanes, PMA/EtOH, U.V.).

The reflux was allowed to continue overnight. After 22 hours of heating, the reaction was cooled to room temperature. Some oily substance dropped out of solution. This oil solidified upon further cooling to room temperature. The solid did not appreciably dissolve upon the addition of -5 ml EtOAc. -3 ml CHCI3 were added to dissolve all solid material.

TLC showed no starting material.

The solution was then washed with 5 ml saturated aqueous NaHC03, dried over Na2S04, filtered, and concentrated to yield 64.3 mg of a partially crystallized yellow oil. 1H and 13C NMR showed cis-oxazoline title product: trans-oxazoline title product: impurity in a ~5:trace:1 ratio.

The trans-oxazoline title product was attributed to a trace amount of (2R,3S)-N-benzoyl-3-phenylisoserine ethyl ester present in the starting material. The product was chromatographed on silica gel with 1 :1 41 CT- EtOAc Hexane 2:1 EtOAc/Hexane, (Rf = 0.57 (1 :1 EtOAc:hexanes) to give 49.3 mg of an oily yellowish solid, yield = 78.4%; 1 H NMR showed the cis and trans oxazoline title products in about a 10:1 ratio (cis:trans).

Example 4 Preparation of f4S-trans)-4.5-Dihvdro-2.4-diphenyl-5-oxazolecarboxvlic acid, methvl ester (a) Benzenecarboximidic acid, ethyl ester. hydrochloride Benzonitrile (30.3 g, 294 mmoles) and ethanol (14.2 g, 308 mmoles) were added to a flame-dried, argon purged 100 ml flask and cooled to 0°C. HCI was bubbled through the stirring solution for 20 minutes, by which time the tare showed that 17.5 g HCI had been added. HCI addition was ceased and the clear solution was stirred at 0°C. A precipitate began to form after about 1 hour.

After stirring at 0°C for about 2 1/2 hours, the heterogeneous mixture was transferred to a 4°C cold room. After 3 1/2 days at 4°C, the solid mass was crushed and triturated with 150 ml of cold 4°C diethyl ether. The mixture was allowed to stand at 4°C for 6 hours. The mixture was vacuum-filtered and quickly washed with 2 x 100 ml cold diethyl ether and dried under high vacuum (0.5 mm Hg for 17 hours) to give 51.6 g (94.5%) of a white free flowing powder of the title product. 42 (4S-transV4.5-Dihydro-2.4-dtphenvl- 5-oxazolecarboxylic acid, methyl ester (2R,3S)-3-Phenylisoserine methyl ester hydrochloride salt (5.76 g, 24.9 mmoles) was dissolved in 1 ,2-dichloroethane (75 ml). Triethylamine (2.77 g, 27.3 mmoles) was added and the resulting mixture was stirred for 15 minutes before the addition of the benzimidate prepared in step (a) above (4.62 g, 24.9 mmoles) in one portion. The mixture was stirred for 10 minutes, then heated to reflux. TLC after 4 1/2 hours of reflux showed the reaction to be complete. (1 :1 ethyl acetate/hexane, PMA/ethanol, U.V.) The reaction mixture was diluted with 50 ml dichloromethane and 150 ml 10% K2CO3 and shaken. The layers were separated, and the aqueous fraction extracted with 3 x 50 ml CH2CI2. The combined organic fractions were washed with 50 ml saturated aqueous NaCI, dried over Na2S04, filtered and concentrated to give a yellow oil which was purified on a silica gel column (dry volume - 750 ml; packed column: 100 mm d x 110 mm I) with 1 :2 ethyl acetate/hexane to give 6.05 g of the title product as a very slightly colored oil which solidified upon standing at room temperature. Yield = 86.4%. 43 CT-2262 Example 5 Preparation of (4S-cis .5-Dihydro-2.4-diphenv[-5-oxazolecarboxylic acid, ethyl ester In a 100 ml flask containing a solution of (2R,3S)-N-benzoyl-3-phenylisoserine ethyl ester (2.00 g, 6.38 mmol) in pyridine (20 ml) at 0°C was added methanesulfonyl chloride (0.52 ml, 6.70 mmol) dropwise over a 2 minute period. The solution was stirred at 0 to 4°C for 90 minutes and then at 65-70°C for 18 hours. (The reaction was monitored by TLC using 1 :2 EtOAc: Toluene as eluent, Rf for the starting material = 0.42, Rf for the mesylate = 0.48 and Rf for the cis-oxazoline title product = 0.78, UV visualization.) The reaction was cooled down to room temperature and diluted with EtOAc (80 ml) and 1/3 saturated CUSO4 solution (80 ml) (1/3 saturated CUSO4 solution was prepared by diluting saturated CUSO4 solution to 1/3 its original concentration). The aqueous layer was separated and extracted with EtOAc (40 ml x 1 ). The combined EtOAc solution was then washed with brine (80 ml x 1 ), dried over Na2S04, filtered, concentrated and azeotroped with heptane (20 ml x 2) to give crude cis oxazoline title product as a solid (1.88 g). It was dissolved in hot EtOAc (8 ml) and then hexane (4 ml) was added. The crystallizing mixture was set aside at room temperature for 20 minutes and then at 4°C for 30 minutes. The solid was filtered, washed with cold 10% EtOAc in hexane and air dried to give 1.34 g (71.3%) of the cis-oxazoline title product having a melting point of 135"C. [a]n=-9.25 (c=1.0,CHCl3).

T-2262 Example 6 Preparation of (4S-transM.5-Dihydro-2.4-diphenyl-5-oxa2olpc¾rboxylin acid (4S-trans)-4,5-Dihydro-2,4-diphenyl-5-oxazolecarboxylic acid, ethyl ester (92 mg, 0.31 1 mmoles) was transferred to a 1 dram vial and dissolved in tetrahydrofuran (THF) (0.8 ml). LiOH (aq., 1 N, 0.343 mmoles) was added dropwise and the resulting biphasic mixture was stirred vigorously at room temperature. Within 5 minutes, a homogeneous solution was obtained. TLC after 45 minutes showed no starting material (1 :1 ethyl acetate (EtOAc)/Hexane, PMA/ethanol (EtOH), U.V).

The solution was cooled to 0°C and further diluted with 2.0 ml THF. The reaction was quenched with 0.34 ml of 1 N HCl (1.1 eq). After warming to room temperature, the solution was diluted with 5 ml EtOAc and 5 ml H2O and shaken. The layers were separated. The aqueous fraction was extracted with 3 x 5 ml EtOAc. (After extractions, aqueous fraction pH ~6). The combined organic fractions were dried over Na2S04, filtered and concentrated to give 72.1 mg of a white solid. Yield = 87%. 1H and 3C NMRs, and Mass. Spec, showed the title product having a melting point of 201-203 . [a]o = +25.6*. [a]578 = +26.9*, [a]546 = +30.7*. [a]436 = +53.8'(c=1.0 CHCI3: CH3OH (1 : 1 )).

- Example 7 Preparation of (4S-trans -4.5-Dihvdro-2.4-diohenvl-5-oxazolecarboxylin (4S-trans)-4,5-Dihydro-2,4-diphenyl-5-oxazolecarboxylic acid, methyl ester (0.509 g, 1.81 mmoles) was added to a 10 ml flask and dissolved in tetrahydrofuran (THF) (4.7 ml). Lithium hydroxide (1 N in H2O, 2.0 ml, 1.99 mmoles) was added dropwise. The Diphasic mixture was stirred vigorously. Within 2 minutes after completion of the lithium hydroxide addition, a clear solution was obtained. TLC after 15 minutes showed that the reaction was complete (1 :1 ethyl acetate:hexane, PMA/ethanol).

The reaction mixture was further diluted with 10 ml THF and the resulting cloudy solution cooled to 0°C. The reaction was quenched by dropwise addition of 2.0 ml of 1 N aqueous HCI. The solution was further diluted with 20 ml ethyl acetate and 15 ml water and shaken. The layers were separated, and the aqueous fraction extracted with 3 x 10 ml ethyl acetate (pH of the aqueous layer after extractions was approximately 6). The combined organic fractions were dried over Na2S04 filtered, and concentrated. The concentrate obtained was soluble in a mixture of benzene and methanol, and less soluble in methanol, CHCI3, ethyl acetate or a mixture of these. The concentrate was dried on high vacuum overnight to yield 0.448 g of the title product as a white solid.

(Yield = 93%). M.P. = 201 -203'. [α]ο = +25.6, [α]578 = +26.9*. [α]546 = +30.7, [α]436 = +53.8\ (c=1.0, CHCI3 : CH3OH (1 :1)).

CT-2262 Example 8 Preparation of f4S-trans)-4.5-Dihvdro-2.4-diDhenvl-5-oxa2olecarboxylic acid Ethanol (0.1 ml) was mixed with tetrahydrofuran (1.0 ml), and the mixture cooled to -78°C. n-Butyllithium (n-BuLi) (2.12M, 0.050 ml) was added dropwise, and the mixture warmed to 0°C. Solid (4S-cis)-4,5-dihydro-2,4-diphenyl-5-oxazolecarboxylic acid, ethyl ester having the structure: (20 mg, 0.0678 mmol) was added and the reaction was stirred for 1 hour (a small amount of water was present). A mixture of cis oxazoline ethyl ester starting material and the corresponding trans oxazoline ethyl ester (5-position inversion) were observed by TLC (very little hydrolysis was noted at this point). The reaction mixture was stirred for another hour and then left with an ice bath overnight (0°C to room temperature). After 18 hours TLC showed mostly the trans acid title product and a trace of the cis ester starting material (solvent systems hexane:EtOAc 2:1 (trace of cis ester) and EtOAc:acetone:H20: eOH 7: 1 :1:1 (title product)).

The reaction was quenched with phosphate (pH = 4.3) buffer, and extracted with ethyl acetate (5 x 10 ml). The organic layer was dried and solvent removed to give -17 mg (93%) of the title product. (NMR showed the trans acid title product). M.P. = 135*C [a]o = -92.5", (c=1.0, CHCI3).

- Example 9 Preparation of (4S-trans - and (4S-cisi- 4.5-Dihvdro-2.4-diDhenyl-5-oxazolecarboxylic acids (4S-cis)-4,5-dihydro-2,4-diphenyl-5-oxazolecarboxylic acid, ethyl ester (202 mg, 0.6890 mmoles) was dissolved in tetrahydrofuran (1.5 ml) and lithium hydroxide (1 N aq., 0.718 ml) was added dropwise. A heterogeneous solution was observed. The reaction mixture was stirred overnight at room temperature, upon which time the solution was clear. (TLC (ethyl acetate: hexane, 1 :1) showed a small amount of starting material. TLC (ethyl acetate: methanol: water: acetone 7:1 :1 :1 ) showed the cis and trans oxazoline title products). 1 N HCI (0.718 ml) was added, followed by saturated NaCI (approximately 10 ml) and ethyl acetate (approximately 10 ml). The water layer was washed with ethyl acetate 5 times (approximately 10 ml) - and the H2O layer which had a pH of -5.5 was further acidified to 3.4 pH and extracted with approximately 10 ml EtOAc. The combined organic layers were dried over MgSC-4, and filtered. The ethyl acetate was evaporated under reduced pressure to yield 183 mg (100%) of a mixture of cis and trans title products (3:1 , cis:trans by 1H NMR).

Example 10 Preparation of 7-Triethvlsilvl 3-M4S-trans 4.5-dihvdro- 2.4-diPhenyl-5-oxazolyl1-carbonynbaccatin HI (a) 7-Triethylsilyl baccatin III (i) [2aR-(2a«,4B.4aB.gB,9g, 11 β, 1 gq, 12a«, 12bff)l- Benzoic acid. 2b-acetvtoxy-2a.3.4.4a.5.6.- 9.10.1 1 .12.12a.12b-dodecahvdro-6.9.1 -tri- hydroxy-4a.8.13.13-tetramethvl-5-oxo-4- f(triethylsily0oxy]-7. -methano-1 H-cvclo- deca(3.4lbenzf1 .2-b1oxet-12-yl ester 10-Desacetylbaccatin III (27.4 g, 50.3 mmol, containing H20: 1.57%, CH3OH: 1.6%, ethyl acetate: 0.09%, and hexane: 0.03%), and 4-dimethylaminopyridine (2.62 g, 21.4 mmol, wt. % H2O (Karl Fisher ("K.F.") = 0.09) were added to a flame-dried, argon-purged 1 L 3-necked flask (equipped with a mechanical stirrer and a digital thermometer) and were dissolved in dry dimethylformamide (122 ml, wt. % H2O (K.F.) = <0.01 ). Methylene chloride (256 ml, wt. % H2O (K.F.) = <0.01) was added (the temperature of the reaction solution rose from 23°C to 25°C during the addition of the methylene chloride) and the resulting homogeneous solution was cooled to -50°C. 49 CT-2262 Triethylamine (16 ml, 120 mmol, wt. % H2O (K.F.) = 0.08) was added dropwise over 3 minutes and the resulting solution was stirred at -50°C for 5 minutes before the dropwise addition of neat triethylsiiyi chloride (18.6 ml, 111 mmol). The addition of triethylsiiyi chloride was conducted over a period of 10 minutes during which the temperature of the reaction did not rise above -50°C. The reaction became very cloudy during the addition of triethylsiiyi chloride.

The resulting mixture was stirred at about -50°C for 1 hour and was then allowed to stand (without stirring) in a -48°C freezer for 22 hours. (A separate experiment showed that stirring the reaction at -48°C for 8 hours resulted in -60 % conversion). The mixture was then removed from the freezer and warmed to about -10°C. TLC analysis of the mixture (solvent: ethyl acetate, stain: phosphomolybdic acid/ethanol) revealed the absence of starting material and showed a single spot for the product (Rf = 0.60). The cold mixture was combined with EtOAc (1 L) and washed with H2O (890 ml).

The resulting aqueous layer was separated and extracted with EtOAc (250 ml). The combined organic layers were washed with 5.7% aqueous NaH2P04 (2 x 250 ml, measured pH of 5.7% aqueous NaH2P04 = 4.30 ± 0.05, measured pH of the combined NaH2PC>4 washings = 5.75 ± 0.05). half-saturated aqueous NaCI (250 ml), saturated aqueous NaCI (250 ml), dried over Na2S04, filtered and concentrated on a rotovap. (All concentrations on the rotovap of this Example were conducted with a water bath temperature of 35°C.) The resulting semi-solid was further dried by exposure to high vacuum (-1 mm Hg for 20 minutes) to give 41.5 g of a white solid. The crude product was then dissolved in CH2CI2 (400 ml) (heating in a 35°C water bath was employed to dissolve the solid), and the volume of the resulting solution was reduced to -150 ml on a rotovap. Crystallization started immediately and the mixture was allowed to stand at room temperature for 1 hour. Hexanes (100 ml) were added and the mixture was gently swirled. The mixture was allowed to stand in a 4°C cold room for 16.5 hours. The solid was filtered, washed with 1:9 CH2Cl2/ exanes (3 x 250 50 CT-2262 ml) on a suction filter, and dried under high vacuum (-0.2 mm Hg for 42 hours) to give 26.1 g (79%) of the title product as a white powder. The mother liquor was concentrated on a rotovap, and the residue was crystallized from CH2CI2 to give 4.5 g (14%) of the title product as white crystals. Recrystallization was conducted in the same manner as with the first crop of product: the solid was dissolved in CH2CI2 (100 ml) without heating, and the volume of the resulting solution was reduced to -7 ml on a rotovap. Crystallization began within 5 minutes. The mixture was allowed to stand at room temperature for 1 hour, then in a 4°C cold room for 42 hours. The crystals were filtered, washed with 1:9 ChteC-te/hexanes (3 x 50 ml) on a suction filter, and dried under high vacuum (-0.2 mm Hg for 18 hours). The 1H NMR of this crop was identical to the 1H NMR of the first crop of product. The combined yield for the two crops was 93% (uncorrected).

Elemental Analysis (%) C35H50O10S1 Calcd. Found C 63.80 63.43 H 7.65 7.66 KF(H20) 0.00 0.00 m.p.: 239-242 °C (decomp.) [ocpo: -53.6° (c 1.0, CHCI3) TLC:Rf= 0.60 (silica gel. EtOAc) Visualized by phosphomolybdic acid/ethanol. 51 CT-2262 (ii) f2aR-f2a«.4fl.4aB.6B.9tt.1 1 B.12«.12a«.12b«^ 6.12b-Bis(acetyloxyVl2-(benzoyloxy)-2a.- 3.4.4a.5.6.9.10.1 .12.12a.12b-dodecahvdro- 9.1 1 -dihvdroxy-4a.8.13.13-tetramethyl-4- f(triethylsilyl)oxy -7.1 1-methano-1 H-cvclo- decaf3.41benzf .2-b)oxet-5-one (7-triethylsilyl baccatin III) The title product from step (i) above (21.4 g, 32.4 mmol) was added to a flame-dried, argon purged 1 L 3-necked flask (equipped with a mechanical stirrer and a digital thermometer) and dissolved in THF (350 ml, freshly distilled from sodium/benzophenone). The resulting solution was cooled to -70°C. A solution of n-butyllithium (n-BuLi) (14.6 ml of a 2.56 M solution in hexanes, 37.3 mmol, titrated in triplicate with diphenylacetic acid in THF at 0°C) was added dropwise over a period of 23 minutes. The temperature of the reaction did not rise above -68°C during the addition. Solids were formed upon the addition of n-BuLi and did not appear to dissolve at -70°C. The resulting mixture was stirred at -70°C for 20 minutes and was then warmed to -48°C. A clear homogeneous solution was obtained upon warming to -48°C.

After stirring at -48°C for 1/2 hour, acetic anhydride (4.6 ml, 49 mmol, distilled (137 - 138°C, 1 atm) under an atmosphere of argon before use) was added dropwise over 7 minutes. The temperature of the reaction did not rise above -45°C during the addition. The resulting solution was stirred at -48°C for 20 minutes and then at 0°C for 1 hour. The solution was diluted with ethyl acetate (350 ml), washed with saturated aqueous NH4CI (250 ml), and the layers were separated. The aqueous layer was extracted with ethyl acetate (200 ml). The combined organic layers were 52 CT-2262 washed with saturated aqueous NaCI, dried over Na2S04, filtered and concentrated on a rotovap. (All concentrations on the rotovap in this Example were conducted with a water bath temperature of 353C.) Exposure of the semi-solid to high vacuum (-1.5 mm Hg for 1/2 hour) gave 24.7 g of a white solid.

The crude product was dissolved in CH2CI2 (300 ml) and the volume of the resulting solution was reduced to -70 ml on a rotovap.

Crystallization began within one minute. The mixture was allowed to stand at room temperature for 45 minutes and then in a 4°C cold room for 18 hours. The crystals were filtered, washed with 1 :9 CH2Cl2/hexanes (3 x 100 ml) on a suction filter, and dried under high vacuum (-0.2 mm Hg for 19 hours) to give 20.9 g (92.0%) of the title product as fine white needles. The mother liquor was concentrated on a rotovap, and the residue was crystallized from CH2Cl2/hexanes to give 0.82 g (3.6%) of the title product as small white crystals.

Crystallization of the mother liquor was conducted as follows: The residue was dissolved in CH2CI2 (10 ml) and the volume of the resulting solution was reduced to -5 ml on the rotovap. After standing at room temperature for 1/2 hour, no crystals had formed. Hexanes (5 ml) were added in 1 ml portions and the solution was swirled. A few crystals were present by this time. The mixture was allowed to stand at room temperature for 1/2 hour (more crystals formed) and then in a 4°C cold room for 18 hours. The crystals were filtered, washed with 1 :9 CH2Cl2/hexanes on a suction filter, and dried under high vacuum (-0.15 mm Hg for 21 hours). The combined yield for the two crops was 95.6%. m.p.=218-2190C (decomp.); [α]22η=-78.4° (c 1.0, CHCI3); TLC:Rf=0.37 (silica gel, 1 :9 acetone: CH2CI2, visualized by phosphomolybdic acid/ethanol). 53 CT-2262 7-Triethylsilyl 13-fK 4S-transV4.5-dihvdro- 2.4-diphenyl-5>oxa2olyn-carbonyl]baccatin ill 7-Triethylsilyl baccatin III prepared in step (a) above (0.209 g, 0.298 mmoles), the oxazoline prepared as the title product of Example 6 (80.2 mg, 0.300 mmoles), dicyclohexylcarbodiimide (DCC) (84 mg, 0.407 mmoles), and 4-dimethyiaminopyridine (D AP) (25 mg, 0.205 mmoles) were added to a 1 dram vial (oven-dried), purged with argon, and suspended in toluene (1.0 ml). After stirring for 1 hour at room temperature, some of the solid had dissolved and the mixture was a yellowish color. The heterogeneous mixture was heated to 85°C. TLC at 2 1/2 hours showed the presence of starting material (1 :1 ethyl acetate:hexane, PMA/ethanol, U.V.). Heating at 85°C was continued.

TLC at 5 hours looked essentially the same. The reaction was allowed to stir at room temperature overnight. After 14 hours at room temperature, TLC remained the same. The heterogeneous mixture was diluted with 1.0 mi ethyl acetate (some precipitate was noted) and the mixture was filtered through a pad of Celite. The Celite was rinsed with 3 x 1 ml ethyl acetate, and the filtrate was concentrated to give 0.349 g of a yellowish solid. 1 H N R showed that the title product and 7-triethylsilyl baccatin III were present in an approximately 8:1 ratio, respectively; some 1 ,3-dicyclohexylurea (DCU), and a trace of either the starting oxazoline or an impurity were also noted.

The mixture was partially separated on silica gel (column: 20 mm diameter x 90 mm length) with 1 :2 ethyl acetate/hexane to 1 :1 ethyl acetate/hexane. During chromatography, TLC analysis revealed a small 54 CT-2262 spot with a slightly lower Rf than the coupled title product. The mixed fractions of this impurity and the coupled product were combined. First spot: coupled title product (0.267 g of an off-white solid, yield = 94%.) (1 H NMR showed an approximately 18:1 ratio of the desired coupled product and the aforementioned impurity); first spot and aforementioned mixed fractions: 11.5 mg of an oil ( H NMR showed an approximately 2:1 ratio of the desired coupled product and a different impurity). M.P. = 139-142'C [a]D = -49.5*. [ct]578 = -52.6*. [a]s46 = -63.5', [a]436 = -157.0', (c=1.0, CHCI3).

Example 11 Preparation of 7-Triethylsilyl 13-ff(4S-transV4.5-dihydro-2.4-diphenyl-5- oxazolylj-carbonyllbaccatin III (4S-trans)-4,5-Dihydro-2,4-diphenyl-5-oxazolecarboxylic acid (96.0 mg, 0.359 mmoles), 7-triethylsiiyl baccatin III (0.252 g, 0.359 mmoles), and 4- dimethylaminopyridine (DMAP)(30 mg, 0.246 mmoles) were added to a flame-dried 1 dram vial, purged with argon and suspended in toluene (1.2 ml). Diisopropylcarbodiimide (DIC)(63 mg, 0.503 mmoles) was immediately added, and the slightly yellowish heterogeneous mixture was stirred at room temperature. As time progressed, a very cloudy yellow solution resulted. At this point, the vial was sealed and immersed in an 80°C oil bath. After 3 hours at ~80°C, a darker orangish solution was obtained. The reaction mixture was directly concentrated. 1H NMR showed -6:1 ratio of the desired coupled product and 7-triethylsiiyl baccatin III. The product was partially purified by silica gel 55 CT-2262 chromatography with 1 :3 EtOAc/Hexane to give 0.300 g of an off-white solid. TLC showed isolated product and diisopropyl urea by-product. 1H NMR showed only the desired coupled product and an impurity in -25:1 ratio, and diisopropyl urea by-product. The ratio of desired coupled product to the diisopropyl urea by-product was -12:1.

From these results, the yield of the desired coupled product was -85%.

M.P. = 139-142 . [a]D = -49.5*. [a]578 = -52.6", [a]s46 = -63.5', [a]436 = -157.0*. (c = 1.0, CHCI3).

Example 12 Preparation of 7-Triethylsilyl 13-ff(4S-trans .5-dihydro-2.5-diphenyl-5-oxazolvn-caroonyllbaccatin III 7-Triethylsilyl baccatin III (abbreviated as "A" in this Example) and (4S-trans)-4,5-dihydro- 2,4-diphenyl-5-oxazolecarboxylic acid (abbreviated as "B" in this Example) were contacted under the conditions set forth in the following Table 1 to prepare the title compound. M.P. = 139-142*C. [α]ο = -49.5*. [α]578 = -52.6*. [a]s46 = -63.5', [a]436 = -157.0*. (c = 1.0, CHCI3). 56 CT-2262 Table 1 EExample B Reagents Concentration Time Temp.

No. (eq.)e (eqr Solvent B (M) (hrs) (°C) 12a 1.2 DCC(1.4) PhCH3 0.29 1 23 DMAP (0.7) 2.5 85 12b 1.0 DCC(1.4) PhCH3 0.30 5.5 85 DMAP (ο.η 12c 1.0 R2POCl (1.04) 1 ,2-DCE 0.28 6 23 DMAP (1.01) 15 55 NEl3(1.04) 12d 1.0 R2POCl(1.01) 1,2-DCE 0.23 5 23 NEl3 (2.0) 16 65 44 75 12e 1.0 CDI(1.2) THF 0.39 21 70 DMAP (1.0) I2f 1.0 ArCOCl (1.5) CH2CI2 0.23 23 23 DMAP (2.0) NB3(1.5) 12g 1.0 ArCOCl (15) PhCH3 0.29 5.5 23 DMAP (2.0) NB3(1.5) 12 1.0 ArCOCl (1 OS) CH2CI2 0.30 3.5 -78 DMAP (2.0) 19 -60 NB3(1.0) 1 0 20 23 57 CT-2262 Table 1 fConf (ft t-BuCOCI (1.1) ' 1,2-DCE 0.28 D AP (2.0) NEt3 (1.2) t-BuCOCI (2.1) 1 ,2-DCE 0.23 DMAP (4.2) NEt3 (2.3) t-BuCOCI (1.0) CH2CI2 0.24 DMAP (0.07) NEt3 (2.0) t-BuCOCI (1.0) Pyridine 0.23 DMAP (0.05) * eq. = equivalents, based on 7-triethyl-silylbaccatin III (amounts of 7-triethylsilyl baccatin III were the following for the above Examples: 12a = 0.061 g; 12b = 0.533 g; 12c = 0.200 g; 12d = 0.161 g; 12e = 0.057 g; 12f = 0.200 g; 12g = 0.203 g; 12h = 0.208 g; 12i = 0.196 g; 12j = 0.165 g; 12k = 0.165 g; 121 - 0.164 g) Kev to Table 1 = bis(2-oxo-3-oxazolidinyl)-phosphinic chloride 58 DCC = dicyclohexylcarbodiimide DMAP = 4-dimethylam inopyridine DIC = diisopropylcarbodiimide ArCOCI = 2,4,6-trichlorobenzoyl chloride = CDI = carbonyl diimidazole t-BuCOCI = pivaloyl chloride 1 ,2-DCE = 1 ,2-dichloroethane NEt3 = triethylamine THF = tetrahydrofuran PhCH3 = toluene 59 CT-2262 Example 2a All reagents were mixed together before addition of the solvent. 108% (90 mg) of the title product was isolated by chromatography (containing about 10% of an impurity). Starting compound A was not visible by N R. (Concentration of B in this Example was 0.29M. A separate experiment wherein DCC (2.0 eq), DMAP (3.0 eq.), DMAP-HCI (2.0 eq.) in CHCI3 and 1.0 eq. of B was employed demonstrated that a molar concentration of 0.07M B did not allow the reaction to proceed rapidly enough to observe the formation of the title product by NMR in 27 hours.) Example 12b All reagents were mixed together before addition of the solvent. The title product was obtained in about a 9:1 ratio to the starting compound A (by NMR). 87% (0.63 g) of the title product was isolated by chromatography.

Exam le 12c All reagents were mixed together before addition of the solvent. The title product was obtained in about a 1 :1 ratio to the starting compound A (by NMR). No further reaction progress was noted after 1 hour.

Example 2d Activated oxazoline B was allowed to form for 1 hour (by addition of R2POCI to starting compound B) before addition of starting compound A.

The title product was obtained in about a 1 :6 ratio to the starting compound A (by NMR). Little reaction progress was noted after 5 hours. 60 CT-2262 Example 12e CDI and the starting compound B were contacted for 1 hour before addition of the starting compound A. DMAP was added at t = 4 hours.

About a 1 :1 :1 ratio of the title compound to the starting material A and an impurity was obtained (by NMR). It was noted that no reaction occurred before addition of the DMAP, and that excessive heating caused some decomposition.

Example 12f ArCOCI was added last. About a 1 :1 ratio of the title product to the starting compound A was obtained (by NMR). No further reaction progress was noted after 1.5 hours.

Example 2g ArCOCI was added last. About a 1 :1 ratio of the title product to the starting compound A was obtained (by NMR). No further reaction progress was noted after 1 hour.

Example 12h ArCOCI was added last. About a 1 :1 ratio of the title product to the starting compound A was obtained (by NMR). No further reaction progress was noted after 3.5 hours.

Example 12i A mixed anhydride was preformed for 1 hour (by addition of t-BuCOCI to starting compound B) before addition of the starting compound A. About a 1 :2 ratio of the title product to the starting compound A was obtained (by NMR). No further reaction progress was noted after 2 hours. 61 CT-2262 Sxampie, i2,i A mixed anhydride was preformed for 1 hour (by addition of t-BuCOCI to starting compound B) before addition of the starting compound A. About a 3:1 ratio of the title product to the starting compound A was obtained (by NMR). No further reaction progress was noted after 1 hour.

Example 12k A mixed anhydride was preformed for 1 hour (by addition of t-BuCOCI to starting compound B) before the addition of the starting compound A.

DMAP was added 1 hour after the starting compound A. About a 1 :4 ratio of the title compound to the starting compound A was obtained (by NMR). No reaction was observed without DMAP; no further reaction progress was noted after 2 hours after DMAP addition.

Example 121 A mixed anhydride was preformed for 1 hour (by addition of t-BuCOCI to starting compound B) before addition of the starting compound A. DMAP was added after 16 hours at 55°C. About a 1 :6 ratio of the title product to the starting compound A was obtained (by NMR). No or very little reaction was observed before addition of the DMAP. 62 CT-2262 Example 13 Preparation of 7-Triethytsilyl 13- ff4S-trans)-4.5-dihvdro-2.4-diphenyl-5- QxazQiyiKarbQPyi] baccatin HI ' (4S-trans)-4,5-Dihydro-2,4-diphenyl-5-oxazolecarboxylic acid (65.0 mg, 0.243 mmoles), 7-triethylsilyl baccatin III (0.142 g, 0.203 mmoles), DCC (75 mg, 256 mmoles), and pyrrolidinopyridine (38 mg, 256 mmoles) were added to a flame-dried 1 dram vial, purged with argon and partially dissolved in toluene (1.0 ml). The resulting yellowish heterogeneous mixture was stirred at room temperature. TLC at 3 hours showed the presence of the title product (1 :1 EtOAahexanes, PMA/EtOH, U.V.) (TLC at 7 and 23 hours after stirring at room temperature showed no further change.) The reaction mixture was diluted with ethyl acetate (1 ml), filtered through a pad of celite and concentrated to give 0.275 g of an oily yellowish solid. 1 H NMR showed the desired coupled title product and 7-triethylsilyl baccatin III in -8:1 ratio. The N-acyl urea by-product of the coupling agent was also present in about the same amount as 7-triethylsilyl baccatin III.

The solid was chromatographed on silica gel with 1 :2 EtOAc/hexane to give 0.176 g of an off-white solid. Yield -91%. 1 H NMR showed only the desired coupled product and the N-acyl urea in -1 1 :1 ratio. 63 CT-2262 Example 14 Preparation of 7-Triethylsilyl 13-f'(4S-trans .5-dihvdro-2.4-diphenyl-5-oxazolyl -carbonvn baccatin III ' (4S-trans)-4,5-Dihydro-2,4-diphenyl-5-oxazolecarboxylic acid (66.7 mg, 0.250 mmoles), 7-triethylsilyl baccatin III (0.146 g, 0.208 mmoles), DCC (79 mg, 0.383 mmoles), and 4-morpholino pyridine (41 mg, 0.250 mmoles) were added to a flame-dried 1 dram vial, purged with argon, and partially dissolved in toluene (1 ml). The resulting yellow heterogeneous mixture was stirred at room temperature. TLC at 3 hours showed the presence of the title product (1 :1 EtOAc:hexane, P A/EtOH, U.V.). (TLC at 7 and 23 hours after stirring at room temperature showed no further change.) The reaction mixture was diluted with ethyl acetate (1 ml), filtered through a pad of Celite, and concentrated to give 0.280 g of a yellowish solid. 1 H NMR showed the desired coupled title product and no 7-triethylsilyl baccatin III (although a trace was visible by TLC). The N-acyl urea by-product from the coupling agent was present in a ratio to title product of -1 :9.

The solid was chromatographed on silica gel with 1 :2 EtOAc:hexanes to give 0.196 g of a white solid. 1 H NMR showed only the coupled title product and the N-acyl urea in about a 15:1 ratio. Yield greater than 90%. M.P. = 139-142'C. [cc]D = -49.5*. [ct]578 = -52.6*. [a]546 = -63.5*. [a]436 = -157.0* (c = 1.0. CHCI3).

CT-2262 Example 15 Preparation of 7-Triethylsilyl 3-tff4S-trans 4.5-dihvdro-2.4-diphenyl-5-oxazolyll-carbonvll baccatin III ' and 7-Trtethylsilyl 13-fr(4S-cis)-4.5-dihydro-2.4-diphenyl-5-oxazolvn-carbonyl] baccatin HI A mixture of the cis and trans oxazoline title products of Example 9 in a 3:1 ratio of cis: trans (100 mg), 7-triethylsilyl baccatin III (219 mg, 0.3121 mmol), DCC (97 mg) and DMAP (23 mg) in toluene (0.9 ml) was prepared. After one hour of heating at 80°C there was a considerable amount of 7-triethylsilyl baccatin III unreacted. Another charge of DMAP (97 mg) and DCC (23 mg) was added, and the mixture heated at 80°C overnight. Small amounts of starting material were observed by TLC (hexane:EtOAc 2:1).

The reaction mixture obtained was diluted with methylene chloride (20 ml), saturated sodium bicarbonate (10 ml, aq.) was added and the water layer was extracted with methylene chloride (2 x 10 ml), and the combined organic layers dried over anhydrous gS04. Upon concentration in vacuo, the product was purified on HPLC (hexane:ethyl acetate 4:1) to give a mixture of the title products containing dicyclohexylurea (DCU). The product had a weight of 260 mg after resuspension in ethyl acetate and removal of some DCU by filtration.

Another HPLC purification gave 1 17 mg of the pure trans title product (40%) and 45 mg of a mixture (-2:1 trans title product: cis title product (15%)). The mixture was purified by preparative TLC (hexanes: ethyl acetate, 1 :1) to give 1 1 mg of the cis title product. 65 CT-2262 Preparation of Taxol The coupled title product obtained in Example 10 above (0.102 g, 0.107 mmoles) was weighed into a 10 ml flask and dissolved in tetrahydrofuran (1.2 ml). Methanol was then added (1.2 ml) and the homogeneous solution cooled to O'C. HCI (aq., 1 N, 0.59 ml, 0.59 mmoles) was added dropwise and the clear homogeneous solution was stirred at 0°C. After 3 hours at 0°C, TLC (1:1 ethyl acetateihexane, PMA/ethanol, U.V.) indicated starting material remained, and the clear homogenous solution was transferred to a 4*C cold room. After 18 hours at 4*C, TLC analysis showed the reaction to be essentially complete (1 :1 ethyl acetate:hexane, PMA ethanol, U.V.). The following compound was obtained: The clear homogeneous solution was warmed to room temperature. 3.5 ml saturated aqueous NaHC03 was added (bubbling was noted) to yield a heterogeneous mixture. Addition of 5 ml tetrahydrofuran and 2 ml water did not significantly enhance the solubility. The heterogeneous mixture was stirred vigorously at room temperature. After stirring at room temperature for 1 hour, a heterogeneous mixture was still present. The mixture was further diluted with 7 ml water and 4 ml tetrahydrofuran. The resulting clear homogeneous solution was stirred at room temperature.

TLC at 2 1/2 hours after NaHC03 addition showed only the presence of taxol (2:1 ethyl acetate/hexane, PMA/ethanol, U.V.). The reaction mixture was diluted with 25 ml ethyl acetate and 25 ml water and shaken. The layers were separated, and the aqueous fraction extracted with 3 x 25 ml ethyl acetate. The combined organic fractions were dried over Na2S04, filtered and concentrated to give 104 mg of a slightly 66 CT- off- white glassy solid. 1 H NMR showed taxol. The solid obtained was purified by chromatography on silica gel (column: 20 mm diameter x 70 mm length) with 2:1 ethyl acetate/hexane to 4:1 ethyl acetate/hexane to give 79.0 mg of the title product as a white solid. Yield = 86.4%.

Exam le 1 Preparation of 7,13-BisTES Baccatin.

Baccatin III (3.102 g, 5.290 mmol) was dissolved in dry DMF (21 mL). To this solution at 0°C was added imidazole (1.80 g, 26.5 mmol), followed by TESCI (4.45 mL. 26.5 mmol). The reaction was stirred at room temperature overnight and diluted with EtOAc (350 mL), and washed with water (4X20 mL) and brine. The organic layer was dried and concentrated in vacuo, the residue was chromatographed (20% ethyl acetate in hexanes) to afford 4.00 g (89.1%) of the desired product. 67 CT- gxample 18 Preparation of 1-DMS-7.13-TES Baccatin 7,13-TES baccatin (2.877 g, 3.534 mmol) was dissolved in dry DMF (17.7 mL). To this solution at 0°C was added imidazole (720.9 mg, 10.60 mmol), followed by dimethylchlorosilane 91.18 mL, 10.60 mmol). The reaction was stirred at that temperature for 45 minutes, and then diluted with EtOAc (300 mL) and washed with water (4X20 mL). The organic phase was dried and concentrated in vacuo. The residue was chromatographed (10% ethyl acetate in hexanes) to afford 2.632 g (85.4%) of the desired product.

Example 19 Preparation of 4-Hvdroxy-7. 3-BisTES-1-D S Baccatin The silylated baccatin derivative of Example 18 (815 mg, 0.935 mmol) was dissolved in THF (15.6 mL). To this solution at 0°C was added Red-Al (0.910 mL, 60% wt, 4.675 mmol). After 40 minutes, the reaction was quenched with saturated sodium tartrate solution (7 mL). After 5 minutes, the reaction mixture was diluted with EtOAc (250 mL).The organic phase was washed with water and brine and dried. The organic layer was then concentrated in vacuo, the residue was chromatographed (10-20% ethyl acetate in hexanes) to afford 590 mg (76.0%) of the desired C4-hydroxyl baccatin analog . 68 CT-2262 Example 20 Preparation of C4-CvcloDropvl ester -7.13-BisT£S-1-D S baccatin The C4-hydroxyl baccatin derivative of Example 19 (196 mg, 0.236 mmol) was dissolved in dry THF (4.7 mL). This solution at 0°C was treated with LHMDS (0.283 mL, 1 M, 0.283 mmol), after 30 minutes at that temperature, cyclopropanecarbonyl chloride (0.032 mL, 0.354 mmol) was added. The reaction was stirred at 0°C for 1 hour and then quenched with saturated NH4CI (3 mL). The reaction mixture was extracted with EtOAc (100 mL), and washed with water and brine. The organic layer was dried and concentrated in vacuo. The resulting residue was chromatographed (10% ethyl acetate in hexanes) to afford 137 mg (65%) of the desired product.

Example 21 Preparation of C4-Cvclopropane ester baccatin 7,13-TES-1-DMS-4-cyclopropane baccatin of Example 20 (673 mg, 0.749 mmol) was dissolved in dry acetonitrile (6 mL) and THF (2 mL). To this solution at 0°C was added pyridine (2.25 mL), followed by 48% HF solution (6.74 mL). After 30 minutes at 0°C, TBAF (2.25 mL, 1 M, 2.25 mmol) was added. Additional dose of TBAF was added until starting 81 CT-2262 The residue was chromatographed (60% ethyl acetate in hexanes) to afford 22 mg (92.4%) of the desired product. 1 H NMR (300 HMz, CDCI3): δ 8.13-8.10 (m, 2H), 7.62-7.45 (m, 3H), 6.42-6.38 (m, 2H), 6.30 (s, 1 H), 6.19 (m, 1 H), 5.65 (d, J=7.1 Hz, 1H), 5.34 (d, J=9.6 Hz, 1 H), 5.18 (d, J=9.8 Hz, 1H), 4.90 (d, J=7.7 Hz, 1H), 4.73 (dd, J=2.0 Hz, J'=5.7 Hz, 1 H), 4.45 (m, 1 H), 4.25 (AB q, J=8.4 Hz, 2H), 3.80 (d, J=7.0 Hz, 1 H), 3.50 (m, 1 H), 3.27 (d, J=5.8 Hz, 1H), 2.61-1.15 (m, 34H, incl. singlets at 2.24, 1.86, 1.68, 1.26, 1.15, 3H each, 1.33, 9H).

Example 39 Preparation of 7.13-TES-1-DMS-4-Butyrate baccatin The C4-hydroxyl baccatin derivative of Example 19 (181 mg, 0.218 mmol) was dissolved in dry THF (4.4 mL). This solution at 0°C was treated with LHMDS (0.262 mL, 1 M, 0.262 mmol), after 30 minutes at that temperature, butyryl chloride (0.034 mL, 0.33 mmol) was added. The reaction was stirred at 0°C for 1 hour and then quenched with saturated NH4CI (3 mL). The reaction mixture was extracted with EtOAc (100 mL), and washed with water and brine. The organic layer was dried and concentrated in vacuo. The resulting residue was chromatographed (10% ethyl acetate in hexanes) to afford 138 mg (70.3%) of the desired product. 82 CT-2262 Example 40 Preparation of C4-Butvrvl ester baccatin 7,13-TES-1-DMS-4-butyrate baccatin of Example 39 (527 mg, 0.586 mmol) was dissolved in dry acetonitrile (19.5 mL). To this solution at 0°C was added pyridine (1.95 mL), followed by 48% HF solution (5.86 mL).

After 30 minutes at 0°C. the reaction mixture was kept at 5°C overnight.

Then diluted with EtOAc (400 mL) and washed with 1 N Hcl, NaHC03 saturated solution, brine and concentrated in vacuo. The residue was chromatographed (60% ethyl acetate in hexanes) to afford 286 mg (80%) of the desired product. .

Example 41 Preparation of 7-TES-4-Butyrate baccatin 4-butyrate baccatin of Example 40 (286 mg, 0.466 mmol) was dissolved in dry DMF (2.3 mL). To this solution at 0°C was added imidazole (127 mg, 1.86 mmol), followed by TESCI (0313 mL, 1.86 mmol). The reaction was stirred at 0°C for 30 minutes and then diluted with EtOAc (100 mL).

The reaction mixture was washed with water and brine and dried then concentrated in vacuo. The residue was chromatographed (30-50% 83 CT- ethyl acetate in hexanes) to afford 283.3 mg (83.5%) of the desired product.

Example 42 Preparation of 2'.7-BisTES-C4-Butyrate Paclitaxel A THF (8.3 mL) solution of the product of Example 41 (300.6 mg, 0.413 mmol) was cooled to -40°C and treated with LH DS (0.619 mL, 0.619 mmol). After 5 minutes, a THF (4.1 mL) of β-lactam of Example 23 (236 mg, 0.619 mmol) was added. The reaction was stirred at 0°C for 1 hour, and then quenched with saturated NH4CI solution (3 mL). The reaction mixture was extracted with EtOAc (150 mL) and washed with water and brine. The organic phase was dried and concentrated in vacuo, the residue was chromatographed (20-30-60% ethyl acetate in hexanes) to afford 377 mg (82.3%) of the desired product.

Example 43 Preparation of C-4-Butyrate Paclitaxel An acetonitrile solution (15.3 mL) of the product of Example 42 (366 mg, 0.334 mmol) was treated at 0°C with pyridine (0.926 mL), followed by 48% HF solution (2.78 mL). The reaction mixture was kept at 5°C 84 CT-2262 overnight and then diluted with EtOAc (200 mL), and washed with water and brine. The organic layer was dried and concentrated in vacuo. The residue was chromatographed (60% ethyl acetate in hexanes) to afford 274 mg (94.5%) of the desired product. 1 H NMR (300 MHz, CDCI3): δ 8.12-8.09 (m, 2H), 7.71-7.32 (m, 13H), 7.00 (d, J=8.9 Hz, 1 H), 6.25 (s, 1 H), 6.16 (m, 1 H), 5.73 (d, J=8.8 Hz, 1H), 5.64 (d, J=7.0 Hz, 1 H), 4.85 (d, KJ=9.4 Hz, 1 H), 4.76 (m, 1H), 4.38 (m, 1 H), 4.20 (AB q, J=8.4 Hz, 2H), 3.77 (d, J=6.9 Hz, 1 H), 3.70 (d, J=4.3 Hz, H), 2.66-0.85 (m, 26H, incl. singlets at 2.20, 1.76, 1.65, 1.21 , 1.1 1 , 3H each, triplet at 0.88, 3H).

Example 4 Preparation of 7. 3-TES-1 -DMS-4-ethyl carbonate baccatin A THF solution (5 mL) of the product of Example 19 (205 mg, 0.247 mmol) was treated at 0°C with LHMDS (0.296 mL, 1 M, 0.296 mmol).

After 30 minutes at 0°C, ethyl chloroformate (0.0354 ml, 0.370 mmol) was added. The reaction was stirred at 0°C for 1 hour and quenched with NH4CI saturated solution (3 mL). The reaction mixture was extracted with EtOAc (100 mL), washed with water and brine. The organic layer was dried and concentrated in vacuo. The residue was chromatographed (10% ethyl acetate in hexanes) to afford 155 mg (69.6%) of the desired product. 85 CT-2262 Example 45 Preparation of C-4 ethyl carbonate baccatin To a acetonitrile solution (5.6 mL) of the product of Example 44 (152 mg, 0.169 mmol) at 0°C was added dry pyridine (0.56 mL), followed by 48% HF (1.69 mL). After 30 minutes at 0°C, the reaction mixture was kept at 5°C overnight. Then the residue was diluted with EtOAc (150 mL), and washed with 1 N HCI and NaHC03 saturated solution. The organic layer was then dried and concentrated in vacuo. The residue was chromatographed (60% ethyl acetate in hexanes to afford 99 mg (95.4%) of the desired product.

Example 46 Preparation of 7-TES-C-4 ethvl carbonate baccatin 4-ethyl carbonate baccatin of Example 45 (95 mg, 0.154 mmol) was dissolved in dry DMF (0.771 mL). To this solution at 0°C was added imidazole (42 mg, 0.617 mmol) and TESCI (104 uL, 0.617 mmol). The reaction mixture was diluted with EtOAc (100 mL) and washed with water and brine. The organic layer was dried and concentrated in vacuo.

The residue was chromatographed (40% ethyl acetate in hexanes) to afford 95 mg (84.4%) of the desired product. 86 CT-2262 Example 47 Preparation of 2'.7-TES-C-4 ethvl carbonate oaclitaxel 7-TES-4-ethyl carbonate baccatin of Example 46 (93.4 mg, 0.128 mmol) was dissolved in THF (2.6 mL). This solution was cooled to -40°C and treated with LHMDS (0.192 mL, 1 , 0.192 mmol), followed by a THF solution (1.3 mL) of (3-lactam of Example 23 (73.1 mg, 0192 mmol). The reaction was kept at 0°C for 1 hour and quenched with NH4CI (3 mL).

The reaction mixture was extracted with EtOAc (100 mL), and washed with water and brine. The organic layer was then dried and concentrated in vacuo, the residue was chromatographed (20-30% ethyl acetate in hexanes) to afford 118 mg (83.0%) of the desired product. 87 CT-2262 Example 48 Preparation of C-4 ethvl carbonate paclitaxel 2',7-TES-4-ethyi carbonate taxol of Example 47 (114 mg, 0.103 mmol) was dissolved in acetonitrile (5.1 mL), to this solution at 0°C was added pyridine (0.285 mL), followed by 48% HF (0.855 mL). The reaction was kept at 5°C overnight. The reaction was then diluted with EtOAc (100 mL), washed with 1 N HCI. NaHC03 saturated solution and brine. The organic layer was dried and concentrated in vacuo. The residue was chromatographed (60% ethyl acetate in hexanes) to afford 75 mg (82.8%) of the desired product. 1H NMR (300 MHz, CDCI3): δ 8.09-8.06 (m, 2H), 7.75-7.24 (m, 13H), 7.14 (d, J=9.0 Hz, 1 H). 6.24 (s, 1 H), 6.10 (m, 1 H), 5.79 (d, J=7.1 Hz, 1 H), 5.66 (d, J=6.9 Hz, 1 H), 4.95 (d. J=8.2 Hz, 1 H), 4.75 (m, 1 H), 4.41-4.16 (m, 5H), 3.89 (d, J=4.3 Hz. 1 H), 3.81 (d, J=6.9 Hz, 1 H), 2.56-1.11 (m, 23H, incl. singlets at 2.21 , 1.75. 1.65, 1.18, 1.1 1 , 3H each, triplet at 1.22, 3H). 88 Example 9 Preparation of 2'.7-silvlated-C-4-butvrate taxane with furyl side chain A THF solution (7.3 mL) of 7-silyl 4-butyrate baccatin of Example 41 (266 mg, 0.365 mmol) was treated at -40°C with LHMDS (0.548 mL, 1 M, 0.548 mmol). After 2 minutes, a THF solution (3.6 ml) of β-lactam of Example 35 (201 mg, 0.548 mmol) was added. The reaction mixture was stirred at 0°C for 1 hour, and quenched with NH4CI saturated solution. The reaction mixture was extracted and washed, dried and concentrated in vacuo. The residue was chromatographed (20% ethyl acetate in hexanes) to afford 399.0 mg (99%) of the desired product.

Example 50 Preparation of C-4 Butyrate taxane with furvl side chain An acetonitrile solution (18.2 mL) of the product of Example 49 (399.0 mg, 0.364 mmol) was treated at 0°C with pyridine (1.01 mL), followed by 48% HF (3.03 mL). The reaction was kept at 5°C overnight, and diluted with EtOAc (200 mL), washed with 1 N HCI, NaHCOa saturated solution, and brine. The organic layer was then dried and concentrated in vacuo. The residue was chromatographed (60% ethyl acetate in hexanes) to afford 305 mg (96.5%) of the desired product. 89 CT-2262 1 H NMR (300 MHz. CDCI3): 5 8.05-8.02 (m, 2H), 7.56-7.35 (m, 4H), 6.33-6.26 (m, 3H), 6.15 (m, 1 H), 5.59 (d, J=7.0 Hz, 1H), 5.40 (d, J=9.7 Hz, 1 H), 5.26 (d. J=9.7 Hz, 1 H), 4.85 (d, J=9.5 Hz, H), 4.66 (m, H), 4.39 (m, 1 H), 4.17 (AB q, J=8.4 Hz, 2H), 3.76 (d, J=6.9 Hz, 1 H), 3.64 (J=6.0 Hz, 1 H), 2.65-0.91 (m, 35H, incl. singlets at 2.18, 1.82, 1.62, 1.21 , 1.09, 3H each, 1.28, 9H, triplet at 0.94, 3H).

Example 51 Preparation of 7.13-BisTES-1 -DMS-C-4 methyl carbonate baccatin The compound of Example 19 (1 18 mg, 0.150 mmol) was dissolved in THF (3 mL). To this solution at 0°C was added LHMDS (0.180 ml_, 1 , 0.180 mmol). After 30 minutes, methyl chloroformate (0.174 mL, 0.225 mmol) was added. After another 30 minutes, the reaction was quenched with NH4C1. The reaction mixture was extracted with EtOAc ( 00 mL).

The organic layer was washed with water (10 mL X 2) and brine (10 mL).

The organic phase was then dried and concentrated in vacuo. The residue was chromatographed (5-10% EtOAc/Hexanes) to afford 104 mg (82.1%) of the desired product. 90 CT-2262 Exam le 52, Preparation of C-4 Methyl carbonate baccatin The compound of Example 51 (89.0 mg, 0.105 mmol) was dissolved in CH3CN (3.5 mL). To this solution at 0°C was added pyridine (0.30 mL), followed by 48% HF (1.05 mL). The reaction was stirred at 0°C for 6 hours, then diluted with EtOAc (100 mL). The reaction mixture was washed with 1 N HCI (10 mL). NaHC03 saturated solution (10 mL X 3).

The organic phase was dried and concentrated in vacuo. The residue was chromatographed (50% EtOAc/Hexanes) to afford 70 mg (100%) of the desired product.

Exam le 53 Preparation of 7-TES-C-4 methyl carbonate baccatin The compound of Example 52 (1 15.5 mg, 0.192 mmol) was dissolved in DMF (0.960 mL). To this solution at 0°C was added imidazole (52.2 mg, 0.767 mmol), followed by TESCI (0.128 mL, 0.767 mmol). After 30 minutes, the reaction mixture was diluted with EtOAc (100 mL). The organic layer was washed with water (10 mL X 2) and brine (10 mL). The organic phase was then dried and concentrated in vacuo. The residue was chromatographed (40% EtOAc/Hexanes) to afford 133 mg (96.8%) of the desired product. 91 CT-2262 Example 54 Preparation of 2'.7-siMated-C-4-methy1 carbonate taxane with fnryl sid chain A THF solution (6.4 mL) of 7-silyl 4-methyl carbonate baccatin of Example 53 (227.8 mg, 0.318 mmol) was treated at -40°C with LH DS (0.350 mL, 1 M, 0.350 mmol). After 2 minutes, a THF solution (3.6 ml) of β-lactam of Example 35 (140 mg, 0.382 mmol) was added. The reaction mixture was stirred at 0°C for 1 hour, and quenched with NH4CI saturated solution. The reaction mixture was extracted and washed, dried and concentrated in vacuo. The residue was chromatographed (20% ethyl acetate in hexanes) to afford 332.0 mg (96.3%) of the desired product.

Example 55 Preparation of C-4-Methyl carbonate taxane with furyl side chain An acetonitrile solution (.15.3 mL) of Example 54 (332.0 mg, 0.307 mmol) was treated at 0°C with pyridine (1.7 mL), followed by 48% HF (5.1 mL).

The reaction was kept at 5°C overnight, and diluted with EtOAc (200 mL), washed with 1 N HCI, NaHCO'3 saturated solution, and brine. The organic layer was then dried and concentrated in vacuo. The residue 92 CT- was chromatographed (60% ethyl acetate in hexanes) to afford 260 mg (99.0%) of the desired product. 1 H NMR (300 MHz, CDCI3): 5 8.05-8.02 (m, 2H), 7.53-7.37 (m, 4H), 6.29-6.15 (m, 4H), 5.62 (d, J=6.9 Hz, 1 H), 5.40 (d, J=9.6 Hz, 1 H), 5.30 (d, J=9.6 Hz, 1 H), 4.91 (d, J=9.3 Hz, 1 H), 4.68 (m, 1 H), 4.34 (m, 1 H), 4.16 (AB q, J=8.5 Hz, 2H), 3.88 (s, 3H), 3.80 (d, J=8.9 Hz, 1 H), 3.69 (d, J=5.5 Hz, 1 H), 2.63-1.08 (m, 28H, incl. singlets at 2.18, 1.85, 1.60, 1.20, 1.08, 3H each, 1.26, 9H).

Example 56 Preparation of 2'.7-silylated-C-4 methyl carbonate paclitaxel Compound of Example 53 (1 13.3 mg, 0.158 mmol) was dissolved in THF (3.16 mL). To this solution at -40°C was added LHMDS (0.237 mL, 1 , 0.237 mmol), followed by β-lactam of Example 23 (90.43 mg, 0.237 mmol). Follow the same procedure as above, 159 mg (91.6%) of the desired product was obtained. 93 CT-2262 Example 57 Preparation of C-4 Methyl carbonate paclitaxet The compound of Example 56 (149 mg, 0.136 mmol) was dissolved in CH3CN (6.8 mL). To this solution at 0°C was added pyridine (0.377 mL), followed by 48% HF (1.132 mL). Follow the same procedure as above, 103.4 mg (87.6%) of the desired product was obtained.

Example 58 Preparation of C-4 Cvctooropvl ester-7-TES-13-oxavol-baccatin To a suspension of the product of Example 22 (72 mg, 0.099 mmol) and the product of Example 6 (29.4 mg, 0.110 mmol) in toluene (2 mL) at room temperature was added D AP (13,4 mg, 0.110). After 10 minutes, DCC(22.6 mg, 0.1 10 ) was added. The reaction mixture was stirred at room temperature for 2 hours. The reaction mixture was then filtered through Celite, rinsed with EtOAc. The organic layer was concentrated in vacuo. The residue was chromatographed (30% EtOAc/Hexanes) to afford desired product (99 mg) in 100% yield. 1 H NMR (CDCI3): δ 8.27-8.24 (m, 2H). 8.03-7.26 (m, 13H), 6.42 (s, 1 H), 6.08 (m. 1 H), 5.67 (d, J=7.0 Hz, 1 H), 5.60 (d, J=6.0 Hz, 1 H), 4.92 (d, 94 CT- J=6.1 Hz, 1 H), 4.87 (d, J=8.3Hz, 1 H), 4.50 (dd, J=6.6 Hz. J'=10.3 Hz. 1 H), 4.16 (AB q, J=8.3 Hz. 2H), 3.85 (d, J=6.9 Hz, 1 H), 2.56-0.52 (m, 39H, incl. singlets at 2.15, 2.02, 1.68, 1.20, 1.18, 3H each, triplet at 0.92, 9H).

HRMS calcd. for C55H66NO13S1 (MH+): 976.4303, found: 976.4271.

Example 59 Preparation of C-4 Cvclopropyl ester of paclitaxel To a solution of the product of Example 58 (83.4 mg, 0.084 mmol) in THF (0.8 ml_) and methanol (0.8 mL) at 0°C was added 1 N HCI (0.42 mL).

The reaction was kept at 4°C for 14 hours. The reaction mixture was warmed to room temperature and NaHCC>3 saturated solution (2.1 mL) was added. The reaction was stirred at room temperature for 3 hours and then poured into H20. the reaction mixture was extracted with EtOAc (4 X 20 mL). The combined organic layer was dried and concentrated in vacuo. The residue was chromatographed (60% EtOAc/hexanes) to afford desired product (45 mg) in 60% yield.

CT-2262 BMS-189892-01 In an oven-dried, argon purged 25 ml flask, BMS-189892-01 (485 mg, 3.0 mmol) (Note 1 ) was dissolved in dry methanol (5.0 ml). To this flask was added trimethylsilyl chloride (326 mg, 3.0 mmol) dropwise via a syringe at O'C. The reaction mixture was stirred at O'C for 5 minutes and then the ice-water bath was removed.- The reaction mixture was further stirred for 14 hours at room temperature. The reaction mixture was concentrated in vacuo and dried under high vacuum to yield 1 quantitatively (691 mg, 100%) as a white foam. 1. Chem Abs.: 34408-064-33.

Example 61 1 2 In a 25 ml flask 1 (691 mg, 3.0 mmol) from above was dissolved in sat.

NaHC03 (10 ml). To this solution was added benzyl chioroformate (512 mg, 3.0 mmol) at room temperature. The reaction mixture was stirred for 14 hours at room temperature during which time a white precipitate formed. The white precipitate was filtered off and washed with water (2 X 5 ml) and hexane 2 x 5 ml). The solid was dried under high vacuum to give 2 as an off white solid (745 mg, 86%). 96 CT-2262 Example 62 In an oven-dried, argon purged 25 ml flask equipped with a Dean-Stark trap, 2 (745 mg, 2.58 mmol) was dissolved in toluene (12 ml) and DMF (2.5 ml). PPTS (502 mg, 2.0 mmol) was added to this solution. The reaction mixture was heated to reflux with stirring for 28 hours. The mixture was diluted with ethyl acetated (50 ml) and was washed with H 0 (20 ml). The aqueous layer was extracted with ethyl acetate (50 ml). The combined organic fractions were dried over MgS04, filtered, and concentrated in vacuo to give crude 3 product (630 mg, 77%) as a dark oil. Crude 3 was purified by column chromatography (silica gel, 2 X 12 cm, 10% ethyl acetate/hexane as eluant) to give 3 as a thick colorless oil (540 mg, 66%).

Example 63 In a 25 ml flask, 3 (540 mg, 2.1 mmol) was dissolved in THF (6 mi) and H20 (3 ml). To this solution was added solid LiOH (82 mg, 2.0 mmol) in one portion at room temperature. The resulting mixrture was stirred for 0.5 hour at room temperature. The reaction was quenched by adding HCI (2.4 ml of a 1.0 N solution) dropwise at room temperature. Next, the mixture was poured into H20 (10 ml), extracted with CH2CI2 (4 X 15 ml), dried over MgSCv. filtered and concnetrated in vacuo to give crude 4 97 (420 mg, 82%) as a yellow oil which was used directly in the next step without further purification.

Example 64 In an oven-dried, argon purged 25 ml flask, 4 (140 mg, 0.54 mmol), BMS- 84260-01 (346 mg, 0.495 mmol) and N,N-dimethyl-aminopyridine (66 mg, 0.54 mmol) were suspended in toluene (10 ml) at room temperature. After stirring the suspension for 20 minutes, 1,3-dicyclohexyicarbodiimide (DCC) (111 mg, 0.54 mmol) was added in one portion and the mixture was stirred at room temperature for 2 hours. Next, N.N-dimethylaminopyridine (66 mg, 0.54 mmol) and 1 ,3-dicyclohexylcarbodiimide (DCC) (111 mg, 0.54 mmol) were added to the reaction mixture. The reaction mixture was stirrred for 14 hours. The mixture was poured into sat. NH4CI (20 ml) and extracted with ethyl acetate (100 ml). The organic extract was filtered through Celite, and the Celite pad was then rinsed with ethyl acetate (4 X 50 ml). The combined organic layers were dried over MgS04, filtered and concentrated in vacuo to give crude 5 (582 mg, 125%). The crude product was purified by column chromatography (silica gel, 2 X 12 cm, 5% ethyl acetate/hexane as eluant) to give 5 (4 3 mg, 89%) as a colorless oil. 98 CT-2262 Example 65 In an oven-dried, argon purged 25 ml flask, 5 (92 mg, 0.094 mmol) was dissolved in THF (2.0 ml) and methanol (2.0 ml). To this flask was added aqueous HCI (0.5 ml of a 2.0 N solution) at 0"C. The solution was then placed in a 6"C cold bath for 1 hours. The reaction mixture was warmed to room temperature and to this flask was added saturated NaHC03 (5.0 ml). The reaction mixture was stirred for 3 hours at room tempearture. The mixture was poured into H20 (10 ml) and extracted with CH2CI2 (4 x20 ml). The combined organic fractions were dried over MgS04, filtered, and concentrated in vacuo to give crude BMS-184060- 01 (70 mg) as a white solid. To a hot solution of the crude BMS-184060- 01 dissolved in CH3OH (3.0 ml), H20 (-1.0 ml) was added till the solution became cloudy. The solution was cooled in a refrigerator over night. The white solid was filtered off using a medium fritted glass filter and dried under high vacuum to give DMG- 104000-01 (51 mg, 64%) as a white solid.

Preparation of C-4 Cyclopropvl ester«7-TES baccatin with a C-l3(Oxayolyl-furyl)side chain To a toluene (2.5 mL) suspension of the product of Example 22 (92.3 mg, 0.127 mmol) and the product of Example 63 (36.0 mg, 0.140 mmol) at room temperature was added DMAP (17.1 mg, 0.140 mmol). After 10 minutes, DCC (28.8 mg, 0.140 mmol) was also added. After 2 hours at room temperature, second dose of reagents were added. The reaction was stirred overnight at room temperature. Then this reaction mixture was filtered and rinsed with EtOAc. The organic layer was concentrated in vacuo. The residue was chromatographed (30% EtOAc/Hexanes) to afford desired product (1 5 mg) in 100% yield.

H NMR (CDCI3): δ 8.20-7.80 (m, 4H). 7.62-7.39 (m, 7H), 6.38 (m, 3H), 6.08 (m, 1H). 5.67 (m, 2H), 5.20 (d, J=5.9 Hz, 1H), 5.20 (d, J-5.9 Hz, 1 H), 4.88 (d, J=9.2 Hz, 1H), 4.49 (dd, J=6.6 Hz, J'=10.2 Hz, H), 4.16 (AB q, J=8.4 Hz, 2H), 3.86 (d, J=6.8 Hz, 1H), 2.54-0.52 (m, 39H, incl. singlets at 2.14, 2.03, 1.67, 1.21, 1.15, 3H each, triplet at 0.91, 9H).

HR S calcd. for C53He Oi Si ( H+): 966.4096, found: 966.4134. 100 CT-2262 Example 67 Preparation of C-4 Cvclopropvl ester taxane with a furvl side chain The compound of Example 66 (69 mg, 0.0715 mmol) was dissolved in THF (1.4 mL) and MeOH (1.4 mL). This solution was then treated at 0°C with N HCI (0.716 mL). After 17 hours at 4°C, the reaction mixture was warmed to room temperature and treated with NaHCO3 saturated solution (6.5 mL). After 6 hours at room temperature, the reaction mixture was extracted with EtOAc (4 X 20 mL). The combined organic layer was cone, in vacuo. The residue was chromatographed (60% EtOAc/Hexanes) to afford desired product (37.4 mg) in 60% yield.

H NMR (CDCI3): δ 8.12-8.09 (m, 2H), 7.74-7.26 (m, 7H), 6.85 (d, J=9.3 Hz, 1 H), 6.39 (s, 2H). 6.30 (s. 1 H), 6.20 (m, 1 H), 5.93 (d, J=9.3 Hz, 1 H), 5.67 (d, J=7.0 Hz, 1 H), 4.88 (s, 1 H). 4.82 (d, J=7.7 Hz, 1 H), 4.42 (m, 1 H), 4.20 (AB q, J=8.5 Hz, 2H). 3.85 (d. J=6.8 Hz, 1 H), 2.54-0.88 (m, 24H, incl. singlets at 2.23, 1.88. 1.67. 1.24, 1.14. 3H each).

HRMS calcd. for C47H52 O15 (MH+): 870.3337, found: 870.3307. 101 CT- Exampie 68 Preparation of C-4 Cvclopropvl ester-2' ethvl carbonate A dichloromethane solution (22.8 mL) of the product of Example 24 (1.333 g, 1.52 mmol) at 0°C was added EtP^N (1.586 mL, 9.10 mmol), followed by EtOCOCI (0.87 mL, 9.10 mmol). The reaction was stirred at 0°C for 6 hours. Then the reaction mixture was diluted with EtOAc (200 mL), washed with water (20 mL X 3) and brine. The organic layer was dried and concentrated in vacuo. The residue was chromatographed (50% EtOAc/Hexanes) to afford desired product (1.281 g) in 88.8% yield together with 86 mg of the starting material (6.5% ). 1H NMR (CDCI3): δ 8.12-8.10 (m, 2H), 7.76-7.26 (m, 13H), 6.90 (d, J=9.4 Hz, 1 H), 6.27 (m, 2H). 6.01 (dd, J=2.1 Hz, J'=9.3 Hz, 1 H), 5.68 (d, J=7.0 Hz.m 1 H). 5.55 (d, J=2.4 Hz. 1 H), 4.83 (d, J=8.2 Hz, 1 H), 4.44 (m, 1H), 4.23 (m, 4H). 3.83 (d. J=7.0 Hz, 1 H), 2.53-0.87 (m, 27H, incl. singlets at 2.22, 1.95, 1.87, 1.67, 1.26, 3H each, triplet at 1.32, 3H).

HRMS calcd. for C52H58NO16 (MH+): 952.3756, found: 952.3726. 102 CT- Example 69 Preparation of C-4 Cvclopropane-2'-ethvl carbonate-7 substituted precursor The 2' Ethyl carbonate of Example 68 (53 mg, 0.056 mmol) was dissolved in D SO (0.5 mL), AC2O (0.5 mL) was then added. The reaction was stirred at room temperature for 14 hours. The reaction mixture was diluted with EtOAc (50 mL), washed with water (5 mL X 3), NaHC03 saturated solution and brine. The organic layer was then dried and concentrated in vacuo. The residue was chrqmatographed (40% EtOAc Hexanes) to afford 56.3 mg of the desired product in 100% yield. 1H NMR (CDCI3): 5 8.10-8.07 (m, 2H). 7.76-7.26 (m, 13H), 6.90 (d, J=9.4 Hz, 1 H), 6.56 (s, 1 H). 6.23 (m, 1 H), 6.03 (d, J=9.5 Hz, 1 H), 5.70 (d, J=6.9 Hz, 1 H), 5.58 (d. J=2.1 Hz. 1 H), 4.84 (d, J=8.9 Hz, 1 H), 4.66 (s, 2H), 4.21 (m, 5H), 3.91 (d. J=6.8 Hz. 1 H), 2.80-0.87 (m, 30H, incl. singlets at 2.17, 2.12. 2.1 1. 1.75. 1.22. 1.20. 3H each, triplet at 1.32, 3H). 103 Example 7Q Preparation of C-4 CvclODroDane-2'-ethvt carbonate-7-ohosphate To a dichloromethane solution (25.7 mL) of the product of (Example 69 (1.30 g, 1.286 mmol) was added 4A sieves (1.30 g), followed by a THF solution (25.7 mL) of NIS (434 mg, 1.929 mmol) and dibenzyl phosphate (537 mg, 1.929 mmol). The reaction mixture was stirred at room temperature, for 5 hours. Then the reaction mixture was filtered through Celite and rinsed with EtOAc. The solvent was removed, and the residue was dissolved in EtOAc (200 mL), washed with 1% NaHS03, brine, and dried over MgSC-4. The organic phase was concentrated in vacuo. The residue was chromatographed (50% EtOAc/Hexanes) to afford .278 g of product in 80.1% yield. 1H NMR (CDCI3): δ 8.10-8.07 (m, 2H), 7.76-7.26 (m, 23H), 6.90 (d, J=9.4 Hz, 1H), 6.35 (s, 1H). 6.23 (m, 1H), 6.02 (d, J=9.5 Hz, 1H), 5.68 (d, J=6.8 Hz, 1H), 5.56 (S, 1H), 5.40 (m, 1H), 5.04 (m, 4H), 4.75 (d, J=9.0 Hz. 1H), 4.20 (m, 5H), 3.89 (d, J=6.8 Hz, 1H), 2.78-0.86 (m, 27H, incl. singlets at 2.18, .99, 1.67, 1.18, 1.05, 3H each, triplet at 1.31, 3H). 104 CT Example 71 Preparation of C-4 Cvclopropane-2'-ethyl carbonate-7-Dhosphate Compound of Example 70 (1.278 g, 1.03 mmol) was dissolved in dry EtOAc (41.2 mL). To this solution was added catalyst Pd/C (438 mg, 10%, 0.412 mmol). The reaction mixture was hydrogenated under 50 Psi for 12 hours. The reaction mixture was then filtered and concentrated in vacuo to give 1.08 g of crude product in 100% yield.

The crude product was carried on for next step without further characterization.

Example 72 Preparation of C-4 Cvclopropane-2'-ethyl carbon ate-7-ohosphate triethanolamine salt To a EtOAc solution (6.8 mL) of the product of Example 71 (1.08 g, 1.02 mmol) was added a 0.100M solution of triethanolamine (6.8 mL, 0. 5 M) in EtOAc. The resulting mixture was placed in -20°C overnight. The mixture was then filtered, the solid was washed with cooled 10% EtOAc/Hexane and dried under vacuum for 12 hours to afford the 105 CT-2262 desired prodrug (1.00 g) in 81.2% yield. The purity of the end product was determined (by HPLC) to be >97% pure. 1 H NMR (CD3OD): δ 8.10-8.07 (m, 2H), 7.80-7.26 (m, 14H), 6.38 (s, 1 H), 6-07 (m, 1 H), 5.89 (d, J=5.2 Hz, 1 Η), 5.63 (d, J=7.0 Hz, 1 H), 5.55 (d, J=5.2 Hz, 1 H), 5.22 (m, 1 H), 4.87 (m, 2H), 4.23 (m, 5H), 3.88 (d, J=7.0 Hz. 1 H), 3.80 (m. 6H), 3.30 (m, 1 H), 3.18 (m, 6H), 2.97-0.86 (m, 26H, incl. singlets at 2.15, 1.94, 1.69, 1.57, 1.13, 3H each, triplet at 1.30, 3H).

HRMS calcd. for C53H61 NO20P ( H+, M=acid): 1062.3525, found: 1062.3550.

Example 73 Preparation of 7-TES-13-T S Baccatin 7-TES baccatin of Example 10 (1.895 g, 2.707 mmol) was dissolved in dry DMF (10.8 mL). To this solution at 0°C was added imidazole (736.4 mg, 10.83 mmol), followed by TMSCI (1.37 mL, 10.83 mmol). The reaction was stirred at 0°C for 1.5 hours. The reaction mixture was then diluted with EtOAc (400 mL). and washed with water (20 mL X 3), brine (15 mL). The organic layer was then dried and concentrated in vacuo.

The residue was chromatographed (20% EtOAc/Hexanes) to afford 1.881 g (90%) of desired product. 106 Example 74 Preparation of 7-TES-i¾-T S-¾-PMS Paccatin 7-TES-13-TMS baccatin of Example 73 (305 mg, 0.430 mmol) was dissolved in dry DMF (2 mL). To this solution at 0°C was added imidazole (87.6 mg, 1.289 mmol), followed by chlorodimethylsilane (122 mg, 1.289 mmol). After 1 hour, the reaction mixture was diluted with EtOAc (150 mL), washed with water ( 0 mL X 3) and brine (10 mL). The resulting organic layer was dried and concentrated in vacuo. The residue was chromatographed (10% EtOAcHexanes) to afford 305 mg (92.4%) of the desired product.

Example.75 Preparation of 7-TES- 3-TMS-1-PMS-C-4 Hydroxy Baccatip 1-D S-7-TES-13-TMS baccatin of Example 74 was dissolved in dry THF (8 mL). To this solution at 0°C was added Red-AI (0.314 mL, 60%, 1.61 mmol). The mixture was stirred at 0°C for 40 minutes, the reaction was then quenched with saturated solution of sodium tartrate (1 mL) for 2 minutes. The reaction mixture was extracted with EtOAc (150 mL), washed with water (15 mL X 2) and brine (15 mL). The organic layer was dried and concentrated in vacuo. The residue was chromatographed (10-20% EtOAc/Hexanes) to afford 143.8 mg (45.3%) of desired product. 107 CT-2262 NMR (300 MHz, CDCI3): d 8.10-8.06 (m, 2H), 7.55-7.39 (m, 3H), 6.39 (s, 1 H), 5.59 (d, J=5.5 Hz, 1 H), 4.68 (dd, J1=3.9 Hz, J2=9.6 Hz, 1 H), 4.61 (m, 1 H), 4.53 (m, 1H). 4.21 (AB q, J=7.8 Hz, 2H), 4.03 (dd. J 1=6.1 Hz, J2=1 1.6 Hz. 1 H), 3.74 (s, 1 H), 3.48 (d, J=5.7 Hz, 1 H), 2.74-0.48 (m, 34H, incl. singlets at 2.15, 2.06, 1.54, 1.16, 0.92, 3H each), 0.28 (s, 9H), -0.015 & -0.32 (doublets, 3H each) Example 76 Preparation of 7-TES-13-TMS-1-DMS-C-4-fOCfO)CH=CH£l Baccatin The compound of Example 75 (99 mg, 0.125 mmol) was dissolved in dry THF (2.5 mL). To this solution at 0°C was added LHMDS (0.150 mL, 1 M, 0.150 mmol). After 30 minutes, acryloyl chloride (0.0153 mL, 0.188 mmol) was added. After another 30 minutes, the reaction was quenched with NH4CI saturated solution. The reaction mixture was extracted with EtOAc (100 mL), and washed with water (10 mL X 2) and brine (10 mL).

The organic phase was dried and concentrated in vacuo. The residue was chromatographed (5-10% EtOAc/Hexanes) to afford 57.5 mg (54.6%) of desired product. 108 CT-2262 Example 77 Preparation of C-4rOCfO)CH=CHg| Baccatin The compound of Example 76 (105 mg, 0.125 mmol) was dissolved in CH3CN (2.5 mL). To this solution at 0°C was added pyridine (0.374 mL), followed by 48% HF (1.12 mL). The reaction was kept at 4°C overnight.

The reaction was then diluted with EtOAc (75 mL). The organic layer was washed with 1 N HCI (5 mL), NaHC03 saturated solution (5 mL X 3) and brine. The organic phase was then dried and concentrated in vacuo. The residue was chromatographed (60% EtOAc/Hexanes) to afford 60.6 mg (81.3%) of desired product.

Example 78 Preparation of 7-TES-C-4fOCfO^CH=CH2| Baccatin The triol of Example 77 (60.0 mg, 0.100 mmol) was dissolved in dry DMF (0.66 mL). To this solution at 0°C was added imidazole (27.2 mg, 0.400 mmol), followed by TESCI (0.0672 mL, 0.400 mmol). After 30 minutes, the reaction was diluted with EtOAc (75 mL), washed with water (5 mL X 3) and brine. The organic layer was then dried and concentrated in vacuo. The residue was chromatographed (40% EtOAc/Hexanes) to afford 56.0 mg (78.4%) of desired product. 109 CT-2262 Example 79 The baccatin of Example 78 (50 mg, 0.0702 mmol) was dissolved in THF (1.4 mL). To this solution at -40°C was added LH DS (0.0843 mL, 1 , 0.0843 mmol), followed immediately by a THF (0.7 mL) solution of β-lactam of Example 23 (40.1 mg, 0.105 mmol). After 2 minutes at -40°C, the reaction was stirred at 0°C for 1 hour. The reaction was then quenched with NH4C1 saturated solution. The reaction mixture was extracted with EtOAc. and washed water. The organic layer was dried and concentrated in vacuo. The residue was chromatographed (20-30% EtOAc/Hexanes) to afford 66 mg (86%) of the desired product.

Example 80 Preparation of C-4iOC(O^CH=CH21 Paclitaxel The compound of Example 79 (46mg, 0.0421 mmol) was dissolved in CH3CN (0.85 mL). To this solution at 0°C was added pyridine (0.125 mL), followed by 48% HF (0.375 mL). The reaction was kept at 4°C overnight. The reaction mixture was then diluted with EtOAc (40 mL), washed with 1 N HCI (3 mL), NaHC03 saturated solution (3 mL X3). The organic layer was dried and concentrated in vacuo. The residue was 1 10 CT-2262 chromatographed (70% EtOAc/Hexanes) to afford 28 mg (76.9%) of the desired product.

Example 81 Preparation of 7.13-Bis-TES-1-DMS-C-4-rCfO CfiH51Baccatin The compound of Example 19 (279 mg, 0.336 mmol) was dissolved in dry THF (7 mL). To this solution at O'C was added LHMDS (0.403 mL, 1 , 0.403 mmol). After 30 minutes, benzoyl chloride (0.0585 mL, 0.504 mmol) was added. After 30 minutes, the reaction was quenched with NH4CI saturated solution. The reaction mixture was extracted with EtOAc (150 mL). The organic layer was washed with water and brine and dried and concentrated in vacuo. The residue was chromatographed (10% EtOAc/Hexanes) to afford 215.5 mg (68.6%) of the desired product.

Preparation of C-4-Benzoyl Baccatin The compound of Example 81. (161 mg, 0.172 mmol) was dissolved in CH3CN. To this solution at 0"C was added pyridine (0.57 mL), followed by 48% HF (1.80 mL). After 5 hours at 4*C, another dose of reagent was added. The reaction was kept at 4*C overnight. The reaction mixture 1 1 1 CT-2262 was then diluted with EtOAc (100 mL), and washed with 1 N HCI (5 mL), NaHC03 (5 mL X 3). The organic phase was dried and concentrated in vacuo. The residue thus obtained was chromatographed (30-50% EtOAc/Hexanes) to afford 48 mg (43.0%) of the desired end product.

Example 83 Preparation of 7-TES-C-4-Benzov! Baccatin The triol of Example 82 (48.0 mg, 0.074 mmol) was dissolved in DMF (0.40 mL). To this solution at 0"C was added imidazole (20.1 mg, 0.296 mmol), followed by TESCI (0.0496 mL, 0.296 mmol). After 30 minutes, the reaction mixture was diluted with EtOAc (45 mL), and washed with water (1 mL X 3) and brine. The organic phase was dried and concentrated in vacuo. The residue was chromatographed (40% EtOAc/Hexanes) to afford 48 mg (85.0%) of the desired end product.

Example 84 Preparation Qf.C.-4-9enzQy» Paclitaxel The compound of Example 83 (364.6 mg, 0.478 mmol) was dissolved in THF (9.6 mL). To this solution at -40 wes added LHMDS (0.718 mL, 1 , 0.718 mmol), followed by β-lactam of Example 23 (273.5 mg, 0.718 mmol). Following the same procedure as in previous examples. 415 mg (75.9%) of compound was obtained. Thereafter the deprotected paclitaxel analogue may be obtained by dissolving the above compound in CH3CN (16.5 mL) and at O'C adding pyridine (0.36 mL) followed by 48% HP (3.0 mL). Following the steps outlined in Example 80, the paclitaxel analogue is obtained in 315 mg (94.8%) yield.

Example 85 Preparation of 4.Cvctobutane taxane with furyl side chain 7-TES«4-cyclobutyl baccatin of Example 27 (154 mg. 0.208 mmol) was dissolved in dry toluene (4 mL). To this solution at room temperature was added free acid of Example 63 (64.2 mg, 0.250 mmol) and DMAP (30.5 mg, 0.250 mmol). After 10 minutes, DCC (51.4 mg, 0.250 mmol) was added. The reaction was stirred for 2 hours, and at this time another dose of DCC/DMAP was added.' The reaction was further stirred for 12 hours. The reaction mixture was then filtered through Celite, and the "cake" was rinsed with EtOAc. The combined organic layer was concentrated in vacuo, and the residue was chromatographed (30-40% 1 13 CT-2262 ethyl acetate in hexanes) to afford 222 mg (100%) of the desired product.

A THF (2 mL) and MeOH (2 ml_) solution of (A) ( 82 mg, 0.186 mmol) was treated at 0'C with 1 N HCI (1.86 mL). After 1 hour at 0*C, the reaction was kept at 4 "C overnight. The reaction mixture was then treated with saturated NaHC03 (9.6 mL). After 5 hours at room temperature, the reaction mixture was diluted with EtOAc (120 mL), and washed with water ( X 10 mL). The organic layer was then dried with gSO_i. and concentrated in vacuo. The residue was chromatographed (40-60% ethyl acetate in hexanes) to afford 77 mg (47%) of the desired product. 1H NMR (CDCI3): 8.15-8.12 (m, 2H), 7.73-7.35 (m, 9H), 6.87 (d, J=9.2 Hz, 1 H), 6.44 (m. 2H), 6.28 (s, 1 H), 6.20 (m, 1 H), 5.89 (d, J=9.2 Hz, 1 H), 5.66 (d, J=7.1 Hz, 1 H), 4.90 (d, J=8.1 Hz, 1 H), 4.85 (s, 1 H), 4.44 (m, 1 H), 4.27 (AB q, J=8.4 Hz. 2H). 3.80 (d. J=7.0 Hz, 1 H), 3.56 (m. 1 H), 2.61-0.92 (m, 25H. incl. singlets at 2.22. 1.83, 1.69, 1.23. 1.13 3H each). 13C NMR (CDCI3): 203.6, 174.4, 172.4, 171.2. 166.9, 166.8, 150.9. 142.5, 142.0, 133.5. 133.3. 132.9. 131.9. 130.1 , 130.0. 129.7, 129.0. 128.5, 127.0, 1 10.8, 108.0, 84.6. 80.8. 78.9, 76.4, 75.4 75.0, 72.5, 72.0, 71.3, 58.5, 50.1 , 45.6. 43.1. 38.8. 35.6. 35.5. 26.7, 25.3, 25.1 , 21.9, 20.7, 18.2, 14.6, 9.5.

HRMS calcd. for C 8H54NO15 (MH+): 884.3493, found: 884.3472. 1 14 CT Example 86 Preparation of Paclitaxel The compound of Example 7(b) was added to a 5 ml flask and dissolved in THF. Methanol was added and the slightly yellowish homogeneous solution was cooled to O'C. HCI was added and the resulting homogeneous solution was stirred at O'C for 1/2 hour and then transferred to a 4"C cold room. After 19 1/2 hours from the addition of HCI, TLC showed no starting material. The reaction solution was added to a flask containing 20 ml of 1/2 saturated solution of NaCI. The resulting heterogeneous mixture was stirred at room temperature for 45 minutes. The mixture was filtered and the solid was washed with 15 ml of H20 and air-dried on the fritted funnel. The white solid was then washed through the frit by dissolution in THF into another flask and concentrated to give 0.169 gr. of a glassy solid. The material was transferred to a vial and dissolved in 1.0 ml of THF. NEt3 (4 eq.; 0.63 mmoles; 88 ml) was added, a precipitate formed. The heterogeneous mixture was stirred at room temperature. TLC showed the reaction to be essentially complete after 4.25 hours after the addition of NEt3. The mixture was diluted with 5 ml EtOAc and 5 ml of H20 and shaken. The layers were separated. The aqueous fraction was extracted twice with 5 ml EtOAc. The combined organic fractions were washed with 5 ml of HCI (in), 5 ml of saturated aqueous NaCI, dried over Na2S0 , filtered and concentrated to give 0.127 gr. of a white solid (paclitaxel) in 93.9% yield.

Claims (4)

115 122 ,990/3 WHAT IS CLAIMED IS:

1. A compound of the formula XIV: OBz wherein: R20 is a hydroxy-protecting group or hydrogen, and R is C(0)R10, wherein R10 is hydrogen, alkyL wherein said alkyl is not methyl; alkenyl, alkynyL cycloalkyl, cycloalkenyL -OR16, aryl or heterocyclo, and R16 is alkyl.

2. A process to produce a compound of the formula: wherein: R20 is a hydroxy-protecting group or hydrogen, and R is C(0)R10, wherein R10 is hydrogen, alkyl, wherein said alkyl is not methyl; alkenyl, alkynyL cycloalkyl, cycloalkenyL -OR16, aryl or heterocyclo, and R16 is alkyl. which process comprises: a) reacting Baccatin ΙΠ with a suitable agent in excess to protect the hydroxy groups at C-7 and C-13 in an inert organic solvent, at from about -30°C to room temperature; b) reacting the product of (a) with a trimethylsilane or dimethylsilane in the presence of a tertiary amine base, at from about -30°C to room temperature: to protect the C-l hydroxy qroup ; 122 ,990/3 116 c) reducing the product of (b) by reaction with red-Al or lithium aluminium hydride at from about -30°C to 0°C to obtain a C-4 hydroxy group ; d) reacting the product of (c) with an acyl chloride, acid anhydride or mixed anhydride in the presence of an alkali metal anion of a secondary amine base, at from about -30°C to room temperature, to obtain the C-4 substi tuted compound ; e) deprotecting the product of (d) by reaction with pyridinium fluoride in acetonitrile, followed by tetrabutylammonium fluoride or casium fluoride in THF, and optionally, f) reacting the product of (e) with a suitable agent to effect protection of the hydroxy group at C-7.

3. A compound according to claim 1 , wherein R is C(0)OCH3.

4. A process according to claim 2, wherein R is C(0)OCH3. For the Applicant WOLFF, BREGMAN AND GOLLER