GB2116180A

GB2116180A - Cephalosporin derivatives

Info

Publication number: GB2116180A
Application number: GB08305940A
Authority: GB
Inventors: Shimpei Aburaki; Hajime Kamachi; Yukio Narita; Jun Okumura; Takayuki Naito
Original assignee: Bristol Myers Co
Current assignee: Bristol Myers Co
Priority date: 1982-03-04
Filing date: 1983-03-03
Publication date: 1983-09-21
Also published as: KR870001986B1; SE8301178L; IE56647B1; IT1170307B; MY8700943A; DD210280A5; GB2116180B; DK156900C; ATA228285A; FI74973C; ES526397A0; ES8507557A1; GR77916B; CA1213882A; NL990039I1; HU193158B; IL68011A0; NL193284C; YU149685A; BE896086A

Abstract

Novel cephalosporin derivatives of the formula <IMAGE> wherein R<1> is hydrogen or a conventional amino-protecting group, and R<2> is a straight or branched alkyl group containing from 1 to 4 carbon atoms, allyl, 2- butenyl or 3-butenyl, or is a group <IMAGE> wherein R<3> and R<4> each are independently hydrogen, methyl or ethyl, or R<3> and R<4>, taken together with the carbon atom to which they are attached, may be a cycloalkylidene ring containing from 3 to 5 carbon atoms, and nontoxic pharmaceutically acceptable salts, physiologically hydrolyzable esters and solvates thereof exhibit potent antibacterial activity and can be incorporated into pharmaceutical compositions.

Description

SPECIFICATION Cephalosporin derivatives Summary of the Invention This invention relates to novel cephalosporin derivatives of the formula

wherein R' is hydrogen or a conventional amino-protecting group, and R2 is a straight or branched alkyl group containing from 1 to 4 carbon atoms, allyl, 2-butenyl or 3-butenyl, or is a group

wherein R3 and R4 each are independently hydrogen, methyl or ethyl, or R3 and R4, taken together with the carbon atom to which they are attached, may be a cycloalkylidene ring containing from 3 to 5 carbon atoms, and nontoxic pharmaceutically acceptable salts, physiologically hydrolyzable esters and solvates thereof. Processes for their preparation are also described.

Description of the Prior Art U.K. Patent Specification No. 1,399,086 contains a generic disclosure encompassing a vast number of cephalosporins of the formula

wherein R is hydrogen or an organic group, R" is an etherifying monovalent organic group linked to the oxygen through a carbon atom, B is

and P is an organic group. However, the 2-aminothiazol-4-yl group is not identified as an R substituent and there is no suggestion that P may be N-methylpyrrolidiniummethyl (or any other fully saturated nitrogen-containing ring which is attached to the 3-methyl moiety via its nitrogen atom and which contains an additional substituent on its nitrogen atom). U.S.Patent 3,971,778 and its divisionals Nos. 4,024,133, 4,024,137, 4,064,346 4,033,950, 4,079,178,4,091,209, 4,092,477 and 4,093,803 have similar disclosures.

U.S. 4,278,793 contains a generic disclosure encompassing a vast number of cephalosporin derivatives of the formula

in which the variables R1, R2, R3, R4, X and A include generic definitions of the corresponding substituents of the compounds of Formula I claimed herein. However, in the 20 columns of definitions of the various substituent groups, the 78 page long table of structural formulae and the 225 examples, there is no disclosure that A may be N-methylpyrrolidiniummethyl (or any other fully saturated nitrogen-containing heterocyclic ring) which is attached to the 3-methyl moiety via its nitrogen atom and which contains an additional substituent on its nitrogen atom.

United Kingdom Patent Specification No. 1,604,971 is concordant thereto and has a substantially identical disclosure. Published United Kingdom Patent Application No. 2,028,305 A, although apparently not formally related, contains the same broad generic disclosure but exemplifies A only as hydrogen.

West German OLS 2,805,655 discloses 7-[2-(2-aminothiazol-4-yl)-2-(syn)methoxyiminoace tamidojcephalosporin acid derivatives of the formula

in which R'NH is an optionally protected amino group, R2 is halogen or an optionally substituted hydroxyl, thiol or amino group, and COOR is an optionally esterified carboxyl group. It is also disclosed that, when R2 is an amino group, it may be disubstituted and the substituents, taken together with the N atom, may form inter alia a pyrrolidino group. However, there is no disclosure of an N-methyl-pyrrolidiniummethyl group (or of any other quaternary ammonium group) and substituent R2 cannot be connected to the 3-position via a methylene group.

U.S. Patent No. 4,278,671 discloses 7-(2-aminothiazol-1 -4-yl) 5-2-(syn)-methoxyiminoacetamido]cephalosporin derivatives of the formula

in which R2NH is an optionally protected amino group and R3 is hydrogen or "the residue of a nucleophilic compound". The term "the residue of a nucleophilic compound" is broadly defined and it is then stated that R3 "may alternatively be a quaternary ammonium group". Pyridinium, variously substituted pyridinium, quinolinium, picolinium and lutidinium are disclosed as quaternary ammonium groups. There is no suggestion that the quaternary ammonium group may consist of a fully saturated nitrogen-containing heterocyclic ring system which is bound via its nitrogen atom and which contains an additional substituent on its nitrogen atom.United Kingdom Patent Specification No. 1,581,854 is concordant thereto and has a substantially identical disclosure. Other patents to the same patentee, which are not formally related but which have similar disclosures, include U.S. Patent 4,098,888 and its divisionals U.S. Patents 4,203,899, 4,205,180 and 4,298,606 and United Kingdom Patent Specification No.

1,536,281.

U.S. Patent No. 4,168,309 discloses cephalosporin derivatives of the formula

wherein R is phenyl, thienyl or furyl; Ra and Rb are independently hydrogen, alkyl, cycloalkyl, phenyl, naphthyl thienyl, furyl, carboxy, alkoxycarbonyl or cyano, or R" and Rb, taken together with the carbon atom to which they are attached, form a cycloalkylidene or cycloalkenylidene ring; m and n are each 0 or 1 such that the sum of m and n is 0 or 1; and R1, together with the nitrogen atom to which it is attached, is broadly defined but may not inter alia be a saturated 5membered ring. The compound having the formula

is exemplified in Example 5 thereof. United Kingdom Patent Specification No. 1,591,439 is concordant thereto and has a substantially identical disclosure.There is no suggestion in this patent that the R substituent may be the 2-aminothiazol-4-yl moiety or that the imino substituent not contain a carboxyl group.

Complete Disclosure This invention relates to cephalosporin derivatives of the formula

wherein R' is hydrogen or a conventional amino-protecting group, and R2 is a straight or branched chain alkyl group containing from 1 to 4 carbon atoms, allyl, 2-butenyl or 3-butenyl, or is a group

wherein R3 and R4 each are independently hydrogen, methyl or ethyl, or R3 and R4, taken together with the carbon atom to which they are attached, may be a cycloalkylidene ring containing from 3 to 5 carbon atoms, and nontoxic pharmaceutically acceptable salts and physiologically hydrolyzable esters thereof. Also included within the scope of this invention are the solvates (including hydrates) of the compounds of Formula I, as well as the tautomeric forms of the compounds of Formula I, e.g. the 2-iminothiazolin-4-yl form of the 2-aminothiazol-4-yl moiety.

As shown in the structural formula, the compounds of Formula I have the "syn" or configuration with respect to the alkoxyimino (or alenyloxyimino) group or the carboxysubstituted alkoxyimino group. Because the compounds are geometric isomers, some of the ''anti" isomer may also be present. This invention comprises compounds of Formula I containing at least 90% of the "syn" isomer. Preferably the compounds of Formula I are "syn" isomers which are essentially free of the corresponding "anti" isomers.

The pharmaceutially acceptable salts of the compounds of Formula I include the inorganic base salts such as the alkali metal salts (e.g. the sodium and potassium salts) and the alkaline earth metal salts (e.g. the calcium salts), ammonium salts, organic base salts (e.g. with triethylamine, procaine, phenethylbenzylamine, dibenzylethylenediamine and other organic bases which have been used in the penicillin and cephalosporin art), and the acid addition salts (e.g.

the salts with hydrochloric, hydrobromic, formic, nitric, sulfuric, methanesulfonic, phosphoric, acetic or trifluoroacetic acid) and other acids which have been used in the penicillin and cephalosporin art. The physiologically hydrolyzable esters include the acyloxyalkyl esters, e.g.

(lower)alkanoyl(lower)alkyl esters such as acetoxymethyl, acetoxyethyl, pivaloyloxymethyl and the like. The base salts and the esters may be formed with either of the carboxyl groups of the compounds of Formula I.

The compounds of Formula I in which R' is hydrogen exhibit high antibacterial activity against various Gram positive and Gram negative bacteria, and are useful in the treatment of bacerial infections in animals, including man. The compounds of Formula I may be formulated for parenteral use in a conventional manner utilizing known pharmaceutical carriers and excipients, and may be presented in unit dosage form or in multi-disage containers. The compositions may be in the form of solutions, suspensions or emulsions in oily or aqueous vehicles, and may contain conventional dispersing, suspending or stabilizing agents. The compositions may also be in the form of a dry powder for reconstitution before use, e.g. with sterile, pyrogen-free water.

The compounds of Formula I may also be formulated as suppositories utilizing conventional suppository bases such as cocoa butter or other glycerides. The compounds of this invention may, if desired, be administered in combination with other antibiotics such as penicillins or other cephalosporins.

When provided in unit dosage forms the compositions will preferably contain from about 50 to about 1 500 mg of the active ingredient of Formulal. The dosage for adult human treatment will preferably be in the range of from about 500 to about 5000 mg per day, depending on the frequency and route of administration. When administered intramuscularly or intravenously to an adult human, a total dosage of from about 750 to about 3000 mg per day, in divided doses, normally will be sufficient, although higher daily doses of some of the compounds may be desirable in the case of Pseudomonas infections.

The preferred compounds of Formula I are those in which R' is hydrogen and R2 is methyl or ethyl or R3 and R4 each are independently hydrogen or methyl. In the most preferred compounds, R2 is methyl or R3 and R4 each are methyl. In the primary evaluation of the compounds of this invention, the Minimum Inhibitory Concentrations (MIC's) of the compounds and two reference compounds (cefotaxime and ceftazidime) were determined by the two-fold serial agar dilution method in Mueller-Hinton agar against 32 strains of test organisms in six groups.The geometric means of the MlC's determined in this test are shown in Tables 1 and 4.

(Cefotaxime; Comparison Compound)

(Ceftazidime; Comparison Compounds)

(Test Compounds) It may be seen that all of the test compounds were more active than cefotaxime against the (G - )-II and (G - )-lll groups of test organisms, with the most preferred Compound la being markedly more active. All of the test compounds were more active than ceftazidime against the (G + )-la and (G + )-lb groups of test organisms, with the most preferred Compound la being markedly more active than ceftazidime against all groups of test organisms except (G - )-lIl, which was somewhat more susceptible to ceftazidime.

The absorption of the most preferred Compound la and of reference compounds (cefotaxime and ceftazidime) were determined in mice following a single intramuscular injection of the test compound (dissolved in p.1 M phosphate buffer; pH 7) at a dosage of 20 mg/kg. Blood samples were collected from the orbital sinuses into heparinized capillary tubes and assayed in Mueller-Hinton medium using Morganella MorganiiA9695 as the test organism. The blood levels at various time intervals, the half-life values (t,/2) and the areas under the curve (AUC) are shown in Table 2.

Tests to identify organisms resistant to the preferred compound of Formula la, cefotaxime and ceftazidime were also conducted. The MIC's of these three compounds against 240 strains of Enterobacteriaceae were determined in Mueller-Hinton medium, and an MIC of equal to or greater than 8 for at least one of the test compounds was arbitrarily taken as indicating a resistant organism. Of the 240 strains, 27 were found to be resistant to at least one of the test compounds. The results, showing 3 organisms resistant to Compound la, 1 5 organisms resistant to ceftazidime and 1 8 organisms resistant to cefotaxime, are given in Table 3.

Table 1 Geometric Mean of MIC (mcg/mL)

(G+)-Ia (G+)-Ib (G-)-Ia (G-)-Ib (G-)-II (G-)-III Compound (5 strains) (5) (5) (6) (5) (6) Ia; R=methyl 1.2 3.1 0.025 0.13 0.33 2.8 Ib; R=ethyl 1.4 3.1 0.087 0.32 1.0 5.6 Ic; R=isopropyl 1.4 3.6 0.35 1.3 3.2 11 Id; R=allyl 1.8 3.6 0.53 1.1 2.4 13 Cefotaxime(a) 1.0 2.2 0.015 0.35 4.1 22 Ceftazidime(a). 5.1 12 0.070 1.7 2.6 1.8 (G+)-Ia : Penicillin-sensitive S. aureus (5 strains) (G+)-Ib : Penicillin-resistant S. aureus (5 strains) (G-)-Ia : Cephalothin-sensitive E. coli (2 strains), Kl. pneumoniae (1 strain) and pr. mirabilis (2 strains) (G-)-Ib : Cephalothin-resistant E. coli (3 strains) and Kl. pneumoniae (3 strains) (G-)-II : Pr. morganii (1 strain), Ent. cloacae (2 strains) and Ser. marcescens (2 strains) (G-)-III :Ps. aeruginosa (6 strains) (a) Mean of five experiments Table 2 Blood Levels After Intramuscular Administration to Mice (20 mg/kg)

Blood Levels (mcg/mL) t1/2 AUC Compound Minutes After Administration (minutes) (mcg.hour/ml) 10 20 30 45 60 90 Ia; R=methyl(a) 20.7 19.6 13.6 8.8 4 ~0.9 17 13.5 Cefotaxime(b) 27.8 29.3 13 9.1 4.6 1.2 15 14.9 Ceftazidime(c) 21.5 18.4 14.9 8.7 4.4 ~0.8 17 13.8 (a) average of 2 tests (b) 1 test (c) average of 3 tests Table 3 Resistance (MIC = 28 yg/ml) to One or More Test Compounds Among 240 Stains of Enterobacteriaceae in Mueller-Hinton Medium No. of Geometric Mean MIC (yg/ml) Organism Strains la Ceftazidime Cefotaxime Escherichia 1 0.25 32 8 coli Escherichia coli 1 4 0.5 8 Klebsiella pneumoniae 1 2 16 0.13 Enterobacter aerogenes 3 0.25 32 13 Enterobacter aerogenes 1 4 8 32 Enterobacter cloacae 1 0.13 4 8 Enterobacter cloacae 3 0.5 40 50 Enterobacter cloacae 3 1.6 > 63 > 63 Enterobacter cloacae 1 > 32 > 63 > 63 Citrobacter freundii 2 0.35 45 32 Citrobacter species 1 0.03 > 63 32 Proteus vulgaris 1 0.06 8 8 Morganella morganii 1 0.06 32 32 Serratia marcescens 1 1 1 1 6 Serratia marcescens 1 2 8 16 Serratia marcescens 2 2.8 2 11 Serratia marcescens 1 4 8 63 Serratia marcescens 1 8 16 8 Serratia marcescens 1 32 > 63 > 63 Total Number of Resistant Strains 27 3 15 18

(Test Compound) Table 4 Geometric Mean of MIC (mcg/mL) Compound Test Compound Organisms le Cefotaximesa) CeftazidimeX (G + )-la (5 strains) 14 1.0 5.1 (G + )-lb (5) 33 2.2 12 (G - )-la (5) 0.066 0.015 0.070 (G-)-lb(6) 0.79 0.35 1.7 (G-)-II(5) 1.2 4.1 2.6 (G - )-lll (6) 4.0 22 1.8 (G + )-la: Penicillin-sensitive S. aureus (5 strains) (G + )-lb: Penicillin-resistant S. aureus (5 strains) (G - )-la: Cephalothin-sensitive E. coli (2 strains), KI. pneumoniae (1 strain) and Pr. mirabilis (2 strains) (G - )-lb: Cephalothin-resistant E. coli (3 strains) and KI. pneumoniae (3 strains) (G - )-Il: Pr. morgani (1 strain), Ent. cloacae (2 strains) and Ser.Mercescens (2 strains) (G - )-III: Ps. aeruginosa (6 strains) (a) Mean of five experiments It may be seen that compound le was more active than cefotaxime against the (G - )-II group of test organisms and markely more active than cefotaxime against the (G - )-lll group of test organisms (Ps. aeruginosa). It was more active than ceftazidime against all groups of Gramnegative test organisms except (G - )-lll (Ps. aeuginosa), which was somewhat more susceptible to ceftazidime.

In another aspect, this invention relates to processes for the preparation of the compounds of Formula I. There are two basic procedures for converting a readily available starting cephalosporin to another cephalosporin having different substituents on the 7- and 3-positions. One may first remove the 7-substituent and replace it with the desired 7-substituent, and then insert the desired 3-substituent. Alternatively, one may first insert the desired 3-substituent and subsequently exchange the 7-substituent. The compounds of Formula I may be prepared by either procedure and both are included within the scope of this invention, but it is preferred to insert the desired 7-substituent first and then insert the desired 3-substituent. The preferred procedure is shown below in Reaction Scheme 1 while the alternative procedure is shown in Reaction Scheme 2. The abbreveiation "Tr" represents the trityl (triphenylmethyl) group, which is a preferred amino-protecting group. The abbreviation "Ph" represents the phenyl group. Thus, the -CH(Ph)2 moiety is the benzhydryl group, which is a preferred carboxyl-protecting group.

Reaction Schemes 3 and 4 show the preparation of Compound (le) in which R1 is hydrogen and R3 and R4 are each methyl.

Reaction Scheme 1

Reaction Scheme 2

Reaction Scheme 3

Although the above Reaction Schemes show preferred multi-step procedures for the preparation of the compounds of Formula I, it will be appreciated that other starting materials and procedures may be utilized to prepare the intermediates used in the key step of each Reaction Scheme. Thus, the key step in Reaction Scheme 1 is the reaction of Compound VII with Nmethylpyrrolidine. Compound VII may itself be prepared by other procedures. Similarly, the key step in Reaction Scheme 2 is the acylation of Compound XII with Compound IV. Both compounds XII and IV may be prepared by other procedures.

The key step in Reaction Scheme 3 is the reaction of Compound Vla with N-methylpyrrolidine. Compound Vla may itself be prepared by other procedures. Similarly, the key step in reaction Scheme 4 is the acylation of Compound XII with Compound Illa'. Both Compounds XII and Illa' may be prepared by other procedures.

The present invention provides a process for the preparation of compounds of the formula

wherein R2 is a straight or branched chain alkyl group containing from 1 to 4 carbon atoms, allyl, 2-butenyl or 3-butenyl, or is a group

wherein R3 and R4 each are independently hydrogen, methyl or ethyl, or R3 and R4, taken together with the carbon atom to which they are attached, may be a cycloalkylidene ring containing from 3 to 5 carbon atoms, and nontoxic pharmaceutically acceptable salts, physiologically hydrolyzable esters and solvates thereof which process comprises reacting a compound of the formula

in which R2 is as defined above, B' is a conventional carboxyl-protecting group and B2 is a conventional amino-protecting group, with N-methylpyrrolidine to produce a compound of the formula

and subsequently removing all protecting groups by conventional means or which comprises reacting a compound of the formula

in which R3 and R4 are as defined above, B' and B3 are conventional carboxyl-protecting groups and B2 is a conventional amino-protecting group, with N-methylpyrrolidine to produce a compound of the formula

and subsequently removing all protecting groups by conventional means.

The reaction is carried out in a non-aqueous organic solvent such a methylene chloride, chloroform, ethyl ether, hexane ethyl acetate, tetrahydrofuran, acetonitrile and the like, or mixtures of such solvents. The reaction is conveniently carried out at a temperature of from about -- 10"C to about + 50"C; we normally prefer to conduct the reaction at room temperature. At least one mole of N-methylpyrrolidine should be used per mole of Compound XIV or XlVa; we normally prefer to utilize from about 50% to 100% excess of N-methylpyrrolidine.

Carboxyl-protecting groups suitable for use as B' and B3 in the above reaction are well-known to those skilled in the art and include aralkyl groups such as benzyl, p-methoxybenzyl, pnitrobenzyl and dipehnylmethyl (benezhydryl); alkyl groups such as t-butyl; haloalkyl groups such as 2,2,2-trichloroethyl, and other carboxyl-protecting groups described in the literature, e.g. in U.K. Patent 1,399,086. We prefer to utilize carboxyl-protecting groups which are readily removed by treatment with acid. Particularly preferred carboxyl-protecting groups are the benzhydryl and t-butyl moities.

Amino-protecting groups suitable for use as B2 are also well-known in the art, and include the trityl group and acyl groups such as chloroacetyl. Amino-protecting groups which are readily removed by treatment with acid, e.g. the trityl group, are preferred.

The present invention also provides a process for the preparation of compounds of the formula

wherein R3 and R4 each are independently hydrogen, methyl or ethyl, or R3 and R4, taken together with the carbon atom to which they are attached, may be a cycloalkylidene ring containing from 3 to 5 carbon atoms, and nontoxic pharmaceutically acceptable salts, physiologically hydrolyzable esters and solvates thereof, which process comprises acylating a compound of the formula

or an N-silyl derivative thereof, in which B' is hydrogen or a conventional carboxyl-protecting group, with an acylating derivative of an acid of the formula

wherein B2 is a conventional amino-protecting group and R2 is as defined above, to produce a compound of the formula

and subsequently removing all protecting groups or acylating compound XVI or an N-Silyl derivative thereof with an acylating derivative of an acid of the formula

wherein B2 is a conventional amino-protecting group, B3 is a conventional carboxyl-protecting group and R3 and R4 each are independently hydrogen, methyl or ethyl, or R3 and R4, taken together with the carbon atom to which they are attached, may be a cycloalkenylidene ring containing from 3 to 5 carbon atoms, to produce a compound of the formula

and subsequently removing all protecting groups.

The acylating derivatives of the acid of Formula XVII or XVlla include the acid halides (and particularly the acid chloride), mixed acid anhdyrides (such as the acid anhydrides formed with pivalic acid or a haloformate such as ethyl chloroformate), and activated esters (such as may be formed with N-hydroxybenztriazole in the presence of a condensing agent such as dicyclohexylcarbodiimide). The acylation may also be effected by use of the free acid of Formula XVII or XVlla in the presence of a condensing agent such as dicyclohexylcarbodiimide, carbonyldiimidazole or an isoxazolium salt. As used herein, the term "acylating derivative" of the acid of Formula XVII or XVlla includes the free acid itself in the presence of a condensing agent such as described above.The preferred acylating derivative of the acid of Formula XVII or XVlla is the acid chloride, preferably used in the presence of an acid binding agent (and particularly a tertiary amine acid binding agent such as triethylamine, dimethylaniline or pyridine).

When the acylation is conducted with an acid halide it is possible to utilize an aqueus reaction medium, but a non-aqueous medium is preferred. When acid anhydrides, activated esters, or the free acid in the presence of a condensing agent, are used for the acylation, the reaction medium should be non-aqueous. Particularly preferred solvents for the acylation reaction are halogenated hydrocarbons such as methylene chloride and chloroform, but tertiary amides such as dimethylacetamide or dimethylformamide may be utilized, as well as other conventional solvents such as tetrahydrofuran, acetonitrile and the like.

The acylation reaction may be conducted at a temperature of from about - 50"C to about + 50"C. However, it is preferably conducted at or below room temperature and most preferably from about - 30"C to about 0 C. It is usually preferred to acylate the compound of Formula XVI with about a stoichiometric amount of the acylating agent of Formula XVII or XVlla, although a small excess (e.g. 5-25%) of the acylating agent may be utilized.

It is preferable that the compound of Formula XVI by acylated in the form of its N-silyl derivative (when utilizing a non-aqueous reaction medium). This is conveniently done in situ by simply adding a suitable silylating agent (e.g. N,O-bistrimethylsilylacetamide) to the solution of compound XVI prior to the addition of the acylating agent of Formula XVII or XVlla. We prefer to utilize about 3 moles of silylating agent per mole of Compound XVI although this is not critical. The silyl compound is readily removed after acylation by the addition of water.

The acylating acids of Formula XVII or XVlla including carboxyl- and amino protected derivatives thereof, are kown in the art or amy be prepared by known procedures. This, (Z)-2-(2t-butoxycarbonylprop-2-oxyimino)-2-(2-tritylamino-thiazol-4-yl)acetic acid (IIIa) was prepared by the general procedure described in U.S. Patent 4.258.041 and United Kingdom Patent Application No. 2,025,398.The melting point reported therein was 152-156 C (decomp.) but, in our hands this compound melted at 174-1 75 C decomp.) Preparation No. 1

Ethyl (Z)-2-Methoxyimino-2-(2-tritylaminothiazol-4-yl)acetate (IIIa) A mixture of ethyl (Z)-2-hydroxyimino-2-(2-tritylamino-thiazo-4-yl) acetate (II) 5.00 g, 10.9 mmoles), CH3I (2.04 mL, 32.8 mmoles) and K2CO3 (4.54 g, 32.8 mmoles)) in dry dimethylsulfoxide (DMSO) (100 mL) was stirred at room temperature overnight and then poured into water (250 mL). The precipitate which formed was collected by filtration, washed with water and dried to give the title compound (5.15 g, quantitative yield). Mp. 1 1 5 C (dec.) NMR: dCDCI3 ppm 1.32 (3H, t), 3.98 (3H, s), 4.30 (2H, q), 6.42 (1H, s), 7.2 (1H, m), 7.25 (15H, s).

Compounds Illb, Illc and Iliad were prepared by the general procedure set forth above, but replacing the methyl iodide with the appropriate iodide.

Literature (1) Compound R2 Yield (%) Mp ("C) Mp ("C) Illa methyl 100 115 (dec.) ca. 120 (dec.) Illb ethyl 67 97-98" Illc isopropyl 26 51-55" lIld allyl * The ester was hydrolyzed without isolation ')Tetrahedrom, 34, 2233 (1978) Preparation No. 2

(Z)-2-Methoxyimino-2-(2-tritylaminothiazol-4-yl)acetic acid (I Va) The ethyl ester Illa prepared in Preparation No. 1 (6.00 g, 1 2.7 mmoles) in ethanol (120 mL) was treated with 2N NaOH (12.7 mL) at room temperature overnight.The reaction mixture was adjusted to pH 8 by the addition of powdered dry ice and the solvent was evaporated under reduced pressure. The residue was dissolved in water (100 mL) and the solution was acidified with 1 N HCI to pH 2 and then extracted with ethyl acetate (3 X 50 mL). The combined extracts were washed with a saturated aqueous NaCI solution, dried and evaporated. The residue was crystallized from ethyl acetate-hexane to afford 5.56 g (yield 98%) of the title product. Mp.

138-143"C (dec.).

NMR: dCDcl3 ppm 3.89 (3H, s), 6.52 (1H, s), 7.2 (15H, s).

Compounds IVb, IVc and IVd were prepared by the general procedure set forth above.

Literature (') Compound R2 Yield (%) Mp ( C, dec.) Mp ( C dec.) IVa methyl 98 138-143 ca. 140 IVb ethyl 85 140-145 not reported IVc isopropyl 85 166-169 ca. 170 IId allyl 66 170-178 ca. 170 ')Tetrahedrom, 34, 2233 (1 978) Preparation No. 3 Benzhydryl 3-Hydroxymethyl- 7-phenylacetamido-3-cephem-4-carboxylate (VIII) To a stirred suspension of phosphate buffer (pH 7, 162.5 mL) and wheat bran (20 g, dry) at room temperature was added 7-phenylacetamidocephalosporanic acid sodium salt (5 gm, 1 2.1 mmoles) in one portion. The progress of the reaction was monitored by HPLC until the hydrolysis was complete (5 hours). The suspension was filtered to remove the wheat bran and the filtrate was cooled to 5-10 C for extractive esterification.To the cooled solution was added methylene chloride (32 mL) followed by a 0.5M solution of diphenyldiazomethane in methylene chloride (24 mL). The pH was then adjusted to 3.0 with 28% phosphoric acid. After 1 hour the reaction mixture was allowed to rise to 20 C. Heptane (56 mL) was slowly added and the resulting crystalline title product was recovered by filtration. Yield of the title product was 3.0 gm (50%).

Preparation No. 4 Benzhydryl 7-Amino-3-chloromethyl-3-cephem-4-carboxylate (V) To a slurry of PCl5 (8.3 g, 40 mmoles) in CH2CI2 (100 mL) was added pyridine (3.2 g, 40 mmoles) and the mixture was-stirred for 20 minutes at 20 C. To the mixture was added benzhydryl 3-hydroxymethyl-7-phenylaceta m ido-3-cephem-4-carboxylate prepared in Preparation No. 3 (5.1 g, 10 mmoles) with stirring at - 40"C, in one portion. The mixture was stirred at - 0 C for 15 minutes and allowed to stand at - 1 0'C to - - 15 C for 7 hours. To the cooled solution (-20 C) was added propane-1,3-diol (10 mL) and the mixture was allowed to stand at 20 C for 16 hours and then at room temperature for 20 minutes with stirring.The resulting solution was washed with ice-water (2 X 20 mL) and saturated aqueous NaCI (10 mL), dried over MgSO4 and concentrated in vacuo. The gummy residue (12 g) was dissolved in a mixture of CHCI3 and n-hexane (2:1), and subjected to chromatography using a silica gel column (200 g) and the same solvent as eluant. Fractions containing the title compound were evaporated in vacuo and the residue triturated with n-hexane to give the title product (2.1 g, 51%), melting at > 11 0 C (dec.).

IR : v KBr 3400, 2800, 1785, 1725 cm-1 UV : #EtOH 265 nm (E1% 160).

max 1cm NMR : DppMmSOd6 + CDCl3 3.69 (2H, s), 4.43 (2H, s), 5.09 (1H, d, J = 4.5Hz), 5.24 ( 1 H, d, J = 4.5'Hz), 6.87 (1H, s), 7.3 (10, m).

Example 1 7-[(Z)-2-Methoxyimino-2-(2-aminothiazol-4-yl)acetamido]-3-[(1-methyl-1-pyrrolidinium)methyl]-3cephem-4-carboxylate (Ia) A. Benzhydryl 3-Chlorometh yl- 7j(Z)-2-meThoxyimino-2-(2-rntylaminothiazol-4-yl)acetamidoj-3-ce- phem-4-carboxylate (Vla') Benzhydryl 7-amino-3-chloromethyl-3-cephem-4-carboxylate prepared in Preparation No. 4 (2.52 mmoles) in CH3CN (57 mL) was treated with bis(trimethylsilyl)acetamide (BSA, 4.09 mL, 1 6.6 mmoles) at room temperature for 50 minutes to give a clear solution. To the solution was added an acid chloride solution, which was prepared from (Z)-2-methoxyimino-2-(2-tritylaminothiazol-4-yl)acetic acid (IVa) (2.04 g, 4.60 mmoles) and PCI5 (1.15 g, 5.52 mmoles) in methylene chloride (20 mL). The mixture was stirred at room temperature for 30 minutes, poured into cold water (200 mL) and extracted with ethyl acetate (3 X 100 mL). The combined extracts were washed with aqueous NaCI, dried and evaporated. The residual syrup (4 g) was chromatographed on a silica gel (150 g) column by eluting with 10:1 and 3:1 mixtures of toluene and ethyl acetate successively. The fractions containing the desired compound were combined and evaporated to afford 2.61 g (68%) of Vla' as an amorphous powder.

NMR: SCDC6 3.50 (2H, s), 4.02 (3H, s), 4.33 (2H, s), 4.98 (1 H, d), 5.87 (1 H, q), 6.65 (1 H, s), 6.90 (1H, s), 7.3 (25H, m).

B. Benzhydryl 3-lodomethyl- 7-[(Z)-2-methoxyimino-2-(2-tritylaminothiazol-4-yl)acetamido]-3-ce- phem-4-carboxylate (Vlla') A mixture of the 3-chloromethyl derivative (Vla') (1.50 g, 1.79 mmoles) and Nal (1.34 g, 8.93 mmoles) in methyl ethyl ketone (30 mL) was stirred at room temperature for 1 hour. After evaporation of the solvent the residue was dissolved in ethyl acetate (100 mL) and washed with water, aqueous Na2S2O3 and aqueous NaCI, dried and evaporated to give the title compound Vlla' (1.47 g, 89%) as an amorphous powder.

NMR: aCDC13 ppm 3.55 (2H, ABq), 4.00 (3H, s), 4.25 (2H, s), 4.97 (1H, d), 5.80 (1H, q), 6.65 (1 H, s), 6.90 (1H, s), 7.3 (25H, m).

C. 7-[(Z)-2-Methxoxyimino-2-(2-aminothiazol-4-yl)acetamido]-3-[(1-methyl-1-pyrrolidinium)methyl] 3-cephem-4-carboxylate (la) A mixture of Vlla' (4.5 g, 4.83 mmoles) and N-methylpyrrolidine (0.65 mL, 6.28 mmoles) in CH2CI2 (45 mL) was stirred at room temperature for 20 minutes. Ether (300 mL) was added to the mixture to separate the quaternary salt of the blocked cephalosporin, which was collected by filtration and treated with 90% trifluoroacetic acid (TFA) (40 mL) at room temperature for 1 hour. The mixture was then evaporated under reduced pressure below 20"C. The residue was triturated with ether to give the TFA salt of la (2.40 g), which was dissolved in methanol (5 mL) and treated with 1 M solution of sodium-2-ethylhexoate (SEH) in ethyl acetate (8 mL) at room temperature for 30 minutes.After the addition of ethyl acetate (100 mL), the precipitate (1.94 g) formed was collected by filtration. HPLC analysis showed that the crude product was 7% pure with a 1:8 ratio of the A3 isomer to the A2 isomer. Purification of the product by HPLC was repeated three times (Lichrosorb RP-18, 8 X 300mm, eluted with 5% aqueous CH3OH or 0.01 M ammonium phosphate buffer (pH 7.2) containing 5% CH3OH to give 35 mg (1.5%) of the title product as a colorless powder. Estimated purity (by HPLC) 90%. Mp. 1 50 C (dec.).

IR: gave cam 1770, 1660, 1620.

UV: h,,aphate buffer,pH7 nm(e) 235(16200), 258(15400).

NMR: ssD2O ppm 2.31 (4H, m), 3.08 (3H, s), 3.63 (4H, m), 4.09 (3H, s), 5.43 (1H, d, J = 4.8 Hz), 5.93 (1H, d), 7.08 (1H, s).

Example 2 7-[(Z)-2-Methoxyimino-2-(2-aminothiazol-4-yl)acetamido]-3-[(1-methyl-1-pyrrolidinium)methyl]-3cephem-4-carboxylate (Ia) To a stirred solution of 20.4 g (21.9 mmoles) of Vlla' in 150 mL of dry methylene chloride was added 2.42 (28.5 mmoles) of 1-methylpyrrolidine in one portion at room temperature. The mixture was stirred for 5 minutes and poured into 1000 mL of ether with vigorous stirring to form a precipitate, which was filtered, washed with ether (5 X 30 mL) and dried in vacuo to give 19.3 g of the blocked product as a pale yellow powder.

IR: pmKB:a cm-1 3400, 1780 (s), 1740, 1675, 1530.

TLC: solvent ethanol-CHCI3 (1:3), Rf = 0.30 (Rf = 0.95 for Vlla').

The solid was dissolved in 185 mL of trifluroacetic acid-water (99:1), stirred for 1 hour at room temperature and concentrated to ca. 30 mL below 1 0 C. The concentrate was poured into 1000 mL of ether with vigorous stirring to form a precipitate, which was filtered, washed with ether (5 x 40 mL) and dried under vacuum to yield 10.6 g of pale yellow powder. The powder was dissolved in 20 mL of methanol and the solution was filtered. To the filtrate was added 45 mL of 0.8M SEH in ethyl acetate. The resultant suspension was poured to 400 mL of ethyl acetate and filtered to give 8.08 g of a solid which was a mixture of the title compound and the corresponding A2 isomer (A3/A2 = 1:8) as shown by HPLC analysis (LichrosorbRP-18, 10-15% methanol in 0.01 M phosphate buffer, pH 7).A second run from 28.9 g (31.0 mmoles) of Vlla' gave 16.0 g of the crude product (A3/A2 = 1:8). Isolation of the desired A3 isomer from the combined crude product (24.08 g) by using preparative HPLC (System 500, Waters Associates, PrepPAK 500/C18, 5-10% CH30H) afforded 769 mg of Compound la.

Example 3 7-[(Z)-2-Methoxyimino-2-(2-(2-aminothiazol-4-yl)acetamido]-3-[(1-methyl-1-pyrrolidinium)methyl]3-cephem-4-carboxylate (la) A series of experiments were conducted to determine the effect of solvent, amount of solvent and reaction time on the yield of Compound la and the 1\3/1X2 ratio in the reaction product. The general procedure was as follows: To a suspension of the 3-iodomethyl derivative Vlla' (45 mg, 0.048 mmole) in the indicated amount of the indicated solvent was added a solution of N-methylpyrrolidine (0.01 mL, 0.097 mmole) in ether (0.1 mL) and the mixture was stirred at room temperature for the indicated period. The reaction mixture was diluted with ether (5 mL) and the resulting precipitate was collected by filtration and mixed with 90% TFA.The mixture was stirred for one hour and evaporated to dryness under reduced pressure below 20 C to give the product. The ratio of A3/A2 in the product was determined by HPLC (Lichrosorb RP-18; mobile phase, 0.01 M ammonium phosphate buffer (pH 7.2) containing 15% CH30H; retention time, A3 6.60 minutes, 2 5.56 minutes). Yield of the product and the ratio of A3/A2 isomers for each experiment are given below.

Ratio of Vlla' (in gms.) to Reaction Experi- Solvent Time Yield Ratio ment No. Solvent (in mL) (Min.) (%) \3/iS2 1 CH2Cl2 1:20 15 73 1/8 2 CH2Cl2-Ether (1/10) 1:100 15 25 4/1 3 Ethyl acetate Ether(1/10) 1:100 15 27 4/1 4 Ethyl acetate-Ether (1/10) 1:100 60 64 2/1 5 Ether 1:100 15 31 6/1 6 Ether 1:100 60 62 3/1 7 Ether 1:60 15 55 3.5/1 8 Ether 1:60 60 82 1/1 Example 4 7j(Z)-2-Ethoxyimino-2-(2-aminothiazol-4-yl)acetamidoj-3j( 1-methyl-i -pyrrolidinium)methyl]-3-ce- phem-4-carboxylate (Ib) A.Benzhydryl 3-Chloromethyl- 7-[(Z)-2-ethoxyimino-2-(2-tritylaminothiazol-4-yl)acetamido]-3-ce- phem-4-carboxylate (Vlb) To a solution of (Z)-2-ethoxyimino-2-(2-tritylaminothiazol-4-yl) acetic acid (IVb) (1.095 g, 2.4 mmoles) in dichloromethane (20 mL) was added phosphorus pentachloride (500 mg). After stirring for 1 hour at room temperature, the mixture was added in one portion to an ice-cooled solution of Compound V (1.083 g, 2.4 mmoles) and BSA (1 mL) in dichloromethane (20 mL).

After stirring for 0.5 hour the reaction mixture was poured into 10% aqueous NaHC03 (200 mL) and extracted with CHCI3 (100 mL). The extract was washed with water, dried over MgSO4, and evaporated under reduced pressure.

The residue was chromatographed on a silica gel column. Elution with CHCI3 gave Vlb as an amorphouse powder, 1.76 g (86%).

NMR: #CDCl3 ppm 1.40 (3H, t, CH2CH3), 3.53 (2H, ABq, 2-CH2), 4.37 (2H, s, -CH2CI), 4.60 (2H, q, -CH2CH3), 4.90 (1 H, d, 6-H), 5.89 (1 H, d, 7-H), 6.88 (1 H, s), thiazole-H), 6.91 (1H, s, benzhydryl-CH.) B. Diphenylmenthyl 7-[(Z)-2-Ethoxyimino-2-(2-tritylaminothiazol-4-yl) acetamidcj-34odomeThyl-3- cephem-4-carboxylate (Vllb) A mixture of Vlb (1.07 g, 1.25 mmoles) and Nal (562 mg, 2.75 mmoles) in acetone (20 mL) was stirred for 1 hour. The mixture was filtered and the filtrate was poured into water and extracted with ethyl acetate. The organic layer was washed successivly with 5% aqueous Na2S2O3, water and saturated aqueous NaCI, dried over MgSO4 and evaporated to give 1.04 g (89%) of Compound Vllb.

NMR: sCDC13 ppm 3.55 (2H, q, 2-CH2), 4.27 (2H, s, CH2-l), 5.02 (1 H, d, 6-H), 5.87 (1 H, d, 7 H), 6.68 (1 H, s, thiazole ring H), 6.93 (1 H, s, benzhydryl-CH).

C. 7-[(Z)-2-Ethoxyimino-2-(2-aminothiazol-4-yl)acetamido]-3-[( 1 -methyl- 1 -pyrrolidinium)methyl]-3- cephem-4-carboxylate (Ib) A mixture Vllb (333 mg, 0.35 mmole) and N-methylpyrrolidine (60 mg, 0.7 mmole in CH2CI2 (5 mL) was stirred for 0.5 hour at room temperature and then evaporated in vacua The residue was washed with ether and dissolved in 90% aqueous TFA. After standing for 0.5 hour at room temperature the mixture was concentrated under reduced pressure. Ether was added to the concentrate to separate the quaternized product, which was collected by filtration and dissolved in a small amount of methanol. The solution was chromatographed on an HP-2column (40 mL).Elution with 30% aqueous CH3OH followed by lyophilizaton afforded 0.062 g of a mixture of the A2 and A3 isomer (A2:53 = 5:1). The mixture was purified by HPLC (Lichrosorb RP-18, 8 X 300 mm, 15% methanol) and the desired A3 isomer (Ib) was isolated as pale yellow powder, 4.9 mg (2.7%).

UV: Phosphate buffer, Ph 7 nm(e) 235 (15000), 258(14000).

NMR #D2O ppm 1.43 (3H, t), 2.33 (4H, m), 3.10 (3H, s, 3.64 (4H, m), 4.36 (2H, q), 5.44 (1H, d), 5.95 (1 H, d), 7.08 (1 H, s).

Example 5 7-[(Z)-2-(2-Propoxyimino)-2-(2-aminothiazol-4-yl)acetamido]-3-[(1-methyl-1-pyrrolidinium)methyl]3-cephem-4-carboxylate (Ic) A. Diphenylmethyl 3-Chloromethyl- 7-[(Z)-2-(2-propoxyimino-2-(2-tritylaminithiazol-1-yl)acetami- do]-3-cephem-4-carboxylate (VIc) A mixture of (Z)-2-(2-propoxyimino)-2-(2-tritylamino-thiazol-4-yl) acetic acid (IVc) (707) mg, 1.5 mmoles) and phosphorus pentachloride (344 mg, 1.65 mmoles) in dichloromethane (14 mL) was stirred at room temperature for 1 hour and poured into a solution of Compound V (677 mg, 1.5 mmoles) and BSA (1.1 mL, 4.5 mmoles) in dichloromethane (15 mL). The reaction mixture was stirred at room temperature for 30 minutes, diluted with ethyl acetate (200 mL), and water (3 X 100 mL), dried over sodium sulfate and evaporated to give 1.4 g (100%) of Compound Vlc.

IR: v Kbr max cm-1 3360, 3020, 3060, 2960, 1785, 1725, 1680, 1520, 1500, 1450, 1375, 1300, 1250, 1160, 1090, 1060, 1010, 990, 840, 740, 700.

UV: #EtOH nm(e) 240 (24600), 260 (20700).

NMR: #CDCl3 ppm 1.35 (6H, d, J = 6Hz), 3.50 (2H, s), 4.35 2H, s), 4.58 (1 H, m, J = 6Hz), 5.00 (1 H, d, J = 4.5Hz), 5.91 H, d-d, J = 4.5 8 9Hz; d by D20, J = 4.5Hz), 6.68 (1 H, s), 6.88 (1 H, s), 7.25 (25H, s).

B. Diphenylmethyl 3-lodomethyl-7-[(Z)-2-(2-propoxyimino)-2-(2-tritylaminothiazol-4-ylacetamido]3-cephem-4-carboxylate (Vllc) A mixture of Compound Vlc (500 mg, 0.55 mmole) and sodium iodide (248 mg, 1.66 mmoles) in acetone (10 mL) was stirrred at room temperature for 50 minutes. After evaporation, the residue was dissolvedin ethyl acetate (15 mL), washed successively with 10% aqueous sodium thiosulfate (10 mL), water (10 mL) and aqueous NaCI (10 mL), dried over sodium sulfate and evaporated to yield 494 mg (90%) of the title compound (Vllc).

IR: vKbr max cm-1 3360, 3040, 3020, 2960, 1785, 1720, 1680, 1600, 1520, 1500, 1450, 1370, 1300, 1230, 1150, 1115, 1080, 990, 900, 840, 750, 700.

UV: AmEtaOaH nm (#) 240 (24900), 260 (19400).

NMR: 6cDc13 ppm 1.30 (6H, d, J = 6Hz), 3.37 # 3.70 (1H each, d, J = 16Hz), 4.22 (2H, s), 4.55 (1H, m, J = 6Hz), 4.95 (1H, d, J = 4.5Hz), 5.83 (1H, d-d, J = 4.5 8 9Hz; d by D2O), 6.66 (1H, s), 6.87 (1H, s), 7.25 (25H, s).

C. 7j(Z)-2-(2-Prnpoxyimino)-2-(2-aminothiazol-4-y)acetamidoj-3-U 1-methyl-i pyrrolidinium)me- thyl]-3-cephem-4-carboxylate (Ic) A mixture of the Compound Vllc (545 mg, 0.55 mmole) and 1-methylpyrrolidine (70 mg, 0,82 mmole) in dichloromethane (10 mL) was stirred at room temperature for 30 minutes and diluted with ether (100 mL). The resulting precipitate was collected by filtration. A solution of the precipitate in 90% TFA (4.5 mL) was stirred at room temperature for 30 minutes and evaporated in vacua The residue was triturated with ether to give 317 mg of the crude product, which was chromatographed on an HP-20 column (50 mL), eluted with water (500 mL) and 30% CH3OH (500 mL).The 30% CH3OH eluate was concentrated and lyophilized to yield 109 mg of a mixture of the A2 and A3 isomers (Q2/A3 = 6/1), 100 mg of which was purified by HPLC (Lichrosorb RP-18, 15% MeOH) to give 5 mg (3%) of the desired title Compound Ic.

UV: A7bUffer nm(e) 236 (15100), 252 (14600).

NMR: AD2 ppm 1.42 (6H, d, J = 6Hz), 2.33 (4H, s), 3.10 (3H, s), 3.65 (4H, s), 3.83 # 4.23 (1 H each, d, J = 17Hz), 5.45 (1 H, d, J = 4.5Hz), 5.95 (1 H, d, J = 4.5Hz), 7.05 (1 H, s).

Example 6 7-[(Z)-2-Allyloxyimino-2-(2-aminothiazol-4-yl)acetamido]-3-[1-methyl-1-pyrrolidinium)methyl]-3cephem-4-carboxylate (Id) A. Benzhydryl 7-[(Z)-2-Allyloxyimino-2-(2-tritylaminothiazol-4-yl) acetamido]-3-chlorometh yl-3ce- phem-4-carboxylate (Vld) To a suspension of Compound V (1.35 g, 3 mmoles) in methylene chloride (20 mL) was added BSA (1.1 mL, 4.5 mmoles), and the mixture was stirred for 30 minutes at room temperature to become a clear solution. A mixture of (Z)-2-allyloxyimino-2-(2-tritylaminothiazol-4yl)acetic acid (IVd) (1.40 g, 3.0 mmoles) and phosphorus pentachloride (690 mg, 3.3 mmoles) in methylene chloride (20 mL) was stirred for 15 minutes at room temperature and poured in one portion into the solution of the trimethylsilyated Compound V.The mixture was stirred for 20 minutes at room temperature and diluted with ethyl acetate (200 mL), washed with aqueous sodium bicarbonate and water, dried and evaporated under reduced pressure. The oily residue was purified by silica gel column chromatography (Wako-gel, C-200, 30 g). The column was eluted with chloroform and the fractions containing the desired product were combined.

Evaporation under reduced pressure afforded the title compound (Vld) as an amorphous powder, yield 2.32 g (89%). Mp. 100-115"C (dec.).

IR: vm83rCm ' 3990, 1790, 1730, 1680, 1530, 1250, 1160, 1020.

NMR: dCDC13 ppm 3.50 (2H, 2-H), 4.32 (2H, s, 3-CH2), 4.6-6.1 (7H, m, CH2CH = CH2 and 6,7 H), 6.70 (1H, s, thiazole-H), 6.90 (1H, s, Ph2CH). 7.1-7.6 (30H, m, phenyl protons).

Anal. Calc'd. for C48H40N5O5S2Cl.1 /3CHCl3: C, 64.05; H, 4.45; N, 7.73; S, 7.08 Cl, 782.

Found: C, 64.13, 63.99; H, 4.61, 4.64; N, 7.50, 7.30; S, 6.85, 6.85; Cl, 7.55, 7.46.

B. Benzhydryl 7-[(Z)-2-Allyloxyimino-2-(tritylaminothiazolJ-4-yl) acetamidoj-3-iodomethyl-3-ce- phem-4-carboxylate (Vlld) A mixture of Compound Vld (2.30 g, 2.65 mmoles) and sodium iodide (2 g, 1 3.3 mmoles) in acetone (15 mL) was stirred for 1 hour at room temperature and then evaporated under reduced pressure. A solution of the oily residue in ethyl acetate (200 mL) was washed with 10% sodium thiosulfate and water, evaporated under reduced pressure to afford Compound VIId as an amorphous powder, which was used in the next step without further purification. Yield 2.52 g (99%).

C. 7-[(Z)-Allyloxyimino-2-(2-aminothiazol-4-yl)acetamido]-3-[(1-methyl-1-pyrrolidinium)methyl] 3-cephem-4-carboxylate (Id) A mixture of Compound VIId (478 mg, 0.5 mmole) and N-methyl-pyrrolidine (0.05 mL, 0.5 mmole) in methylene chloride (5 mL) was stirred for 20 minutes at room temperature and diluted with ether (50 mL) to precipitate the quaternized product (yield 500 mg). A mixture of the quaternized product and TFA (2 mL) was allowed to stand at room temperature for 1.5 hours and diluted with ether to precipitate the crude TFA salt of the product (yield 265 mg), which was chromatographed on a column of HP-20 (1.8 X 18 cm). The column was eluted with water and 30% aqueous methanol. The methanolic eluate was evaporated under reduced pressure and the residue was freeze-dried to give an amorphous powder (yield 124 mg), which contained the desired product (17%) and the corresponding # isomer (83%). The mixture was purified by HPLC (Lichrosorb RP-18; 0.01 NH4H2PO4 (pH 7): CH30H = 85:15). The eluate was acidified to pH 3 with dilute HCI and chromatographed on a column of HP-20 (1.8 X 10 cm). The column was eluted with water and then with 30% aqueous methanol. The methanolic eluate was evaporated under reduced pressure and the residue was freeze-dried to afford the title compound (Id) as an amorphous powder (yield 13 mg, 5.1%). Mp. 155 C (dec).

IR: vKBr max cm-1 3600-2800, 1770, 1670, 1610, 1530, 1200.

UV: #max ph 7 buffer nm(#) 235 (16600), 253 (15600).

NMR ssD20 ppm 2.1-2.5 (4H, m, pyrrolidine-H), 3.10 (3H, s, NCH3), 3.4-3.8 (4H, m, pyrrolidine-H), 5.95 (1H, d, 4Hz, --H), 7.10 (1H, s, thiazole-H).

Example 7 7-[2-(2-Aminothiazol-4-yl)-(Z)-2-(2-carboxyprop-2-oxyimino)-acetamido]-3-[(1-methyl-1-pyrrolidinium)methyl]-3-cephem-4-carboxylate (le) A. Benzhydryl 3-Chlorometh yl- 7-[(Z)-2-(2-butoxycarbonylprop-2-oxyimino-2-(2-tritylaminothiazol- 4-yl)acetamido]-3-cephem-4-carboxylate (Va) Procedure 1 A mixture of (Z)-2-(2-t-butoxycarbonylprop-2-oxyimino)-2-(2-tritylam inoth iazol-4-yl)acetic acid (Illa') (1.94 g, 3.6 mmoles) DDC (742 mg, 3.6 mmoles) and N-hydroxybenztriazole (486 mg, 3.6 mmoles) in tetrahydrofuran (THF) (45 mL) was stirred at room temperature for 45 minutes, during which dicyclohexylurea separated. The dicyclohexylurea was removed by filtration and the filtrate was mixed with V (1.5 g, 3.6 mmoles).The mixture was stirred overnight at room temperature and then evaporated in vacua The residual oil was dissolved in CHCl3 (20 mL), washed with saturated aqueous NaHCO3 and saturated aqueous NaCI, dried over MgSO4 and evaporated to dryness. The residue (3.9 g) was dissolved in n-hexane : CHCl3 (1:2) and passed through a silica gel column (40 g) using the same solvent system. Fractions containing the title compound were evaporated in vacuoto give 1.3 g (39%) of Va melting at > 100 C (dec.).

IR: vKBr max cm-1 3990, 1790, 1715, 1690.

UV: #max EtOH nm 240 (E1cm 1% 280), 265 (E1cm 1% 190).

NMR: #CDCl2 ppm 1.45 (9H, s), 1.63 ## 81.66 (6H, each s), 3.49 (2H, broad s), 4.34 (2H, s), 4.96 (1H, d, J = 4.5Hz), 5.90 (1 H, d-d, J = 4.5 & 7.5), 6.66 (1H, s), 6.86 (1 H, s), 7.0-7.5 (25H, m), 8.23 (1 H, d, J = 7.5Hz).

Procedure 2 A solution of V (1.86 g, 4.49 mmoles) in CH3CN (46.5 mL) was treated with BSA (3.33 mL, 1 3.5 mmoles) at room temperature for 50 minutes to give a clear solution.To the solution was added an acid chloride solution which had been prepared from Illa' (2.56 g, 4.49 mmoles) and PCl5 (1.12 g, 5.38 mmoles) in methylene chloride (26 mL). The mixture was stirred at room temperature for 30 minutes, poured into cold water (100 mL) and extracted with ethyl acetate (3 X 50 mL). The combined extracts were washed with aqueous NaCI, dried and evaporated.

The residual syrup (5 g) was chromatographed on a silica gel (100 g) column by eluting with 10:1 mixture of toluene and ethyl acetate. The fractions containing the desired compound were combined and evaporated to afford 2.84 g (65%) of Va.

B. Benzhydryl 7-[(Z)-2-(2-t-Butoxycarbonylprop- 1 yimino)-2-(2-tritylaminothiazol-4-yl)acetamido]-3-iodomethyl-3-cephem-4-carboxylate (VIa) A mixture of Va (500 mg, 0.53 mmole) and Nal (240 mg, 1.6 mmoles) in acetone (3 mL) was stirred for 2 hours at room temperature and then evaporated in vacua To the residue were added CH2CI2 (20 mL) and water (10 mL). The organic layer was washed with 10% s/v sodium thiosulfate (5 mL) and aqueous NaCI (5 mL), dried over MgSO4 and evaporated to dryness to give 540 mg (90%) of Vla as an amorphous powder melting at 106 C (dec.).

IR: vKBr max cm-1 3350, 1790, 1690.

UV: #EtOH max nm 240 (E1cm 1% 270), 265 (E1cm 1% 190).

NMR: #CDCl3 ppm 1.44 (9H,s), 1.65 (6H,s), 3.54 (1H, 4.28(2H, s), 4.98(1 H, d, J =4.5Hz), 5.85(1 H, d-d, J = 4.5 8 7.5Hz), 6.70(1 H, s), 6.90(1 H, s), 7.1 -7.5(25H,m).

C. 7-[2-(2-Aminothiazol-4-yl)-(2)-2-(2-carboxyprop-2-oxyimino)-aceedamido]-3-[(1-methyl-1-pyrrolidinium)methyl]-3-cephem-4-carboxylate (le) A mixture of the iodomethyl derivative Vla (538 mg, 0.51 mmole) and N-methylpyrrolidine (0.079 mL, 0.076 mmole) in CH2CI2 (10.8 mL) was allowed to stand at room temperature for 30 minutes and then diluted with ether (80 mL). The precipitate which formed was collected by filtration and washed with ether to give 420 mg of the quaternized product, which was deblocked with 90-% trifluoroacetic acid (TFA) (4.2 mL) at room temperature for 1 hour. The reaction mixture was then evaporated to dryness. To the residue was added either to give crude TFA salt of la (245 mg, quantitative), which was a 1:4 mixture of the A3 and A2 isomers.The crude was subjected to HPLC purification [Lichrosorb RP-18, 4 X 300 mm, eluted with 0.01 M ammonium phosphate buffer (pH 7.0) containing 10% CH3OH]. The fraction containing the desired product was collected and evaporated to a small volume. The concentrate was adjusted to pH ca. 2 by adding 1 M HCI and passed through an HP-20 column (2 X 15 cm) to remove the inorganic salt. The column was washed with H20 (1000 mL) and eluted with 30% CH3OH.

The eluant was evaporated and lyophilized to afford 21 mg (10%) of the title product (le) as a colorless powder. Mp. 160"C (dec.).

IR: pmKBaTx cm 1 3400, 1775, 1610.

UV: o:Phata buffer. pH-7/nm(8) 237 (15700), 257 (155500).

NMR: SD2o ppm 1.65 (6H, s), 2.3 (4H, m), 3.09 (3H, s) 3.6 (4H, m), 4.0 (2H, m), 5.44 (1 H, d, J = 4.8Hz), 5.94 (1H, d), 7.15 (1H, s).

Example 8 The general procedure of Example 7 is followed except that the (Z)-2-(2-t-butoxycarbonylprop2-oxyimino)-2-(2-tritylaminothiazol-4-yl) acetic acid is replaced by an equimolar amount of (Z)-2-(t-butoxycarbonylmethoxyi mino)-2-(2-trityla minothiazol-4-yl)acetic acid, (Z)-2-( 1 -t-butoxycarbonylethoxyi mino)-2-(2-tritylaminothiazol-4-yl) acetic acid, (Z)-2-(2-t-butoxycarbonylbut-2-oxyim ino)-2-(2-tritylaminothiazol-4-yl-acetic acid, (Z)-2-(3-t-butoxycarbonylpent-3-oxyimino) 1 -(2-tritylam inoth iazol-4-yl) acetic acid, (Z)-2-( 1 -t-butoxycarbonylcycloprop- 1 -oxyimino)-2-(2-trityla minothiazol-4-yl)acetic acid, (Z)-2-( 1 -t-butoxyearbonylcyclobut- 1 -oxyi mino)-2-(2-tritylaminothiazol-4-yl)acetic acid and (Z)-2-( 1 -t-butoxycarbonylcyclopent- 1 -oxyimi no)-2-(2-tritylam i nothiazol-4-yl)acetic acid, respectively, and there is thereby produced 7-[2-(2-aminothiazol-4-yl)-(Z)-2-(carboxymethylimino)acetamido]-3-[(1-methyl-1-pyrrolidinium) methylj-3-cephem-4-carboxylate, 7-[2-(2-aminothiazol-4-yl)-(Z)-2-(1 -carboxyethoxyi mino)acetamido]-3-[(1 methyl 1 -pyrrolidinium)methyl]-3-cephem-4-carboxylate, 7-[2-(2-aminothiazol-4-yl)-(Z)-2-(2-carboxybut-2-oxyimino)-acetamido]-3-[(1-methyl-1-pyrrolidinium)methyl]-3-cephem-4-carboxylate, 7-[2-(2-aminothiazol-4-yl)-(Z)-2-(3-carboxypent-3-oxyimino)-acetamido]-3-[(1-methyl-1-pyrrolidinium)methyl]-3-cephem-4-carboxylate, 7-[2-(2-aminothiazol-4-yl)-(Z)-2-(1-carboxycycloprop-1-oxyimino)-acetamido]-3-[(1-methyl-1-pyrrolidinium)methyl]-3-cephem-4-carboxylate, 7-(2-(2-a minoth iazol-4-yl)-(Z)-2-( 1 -carboxycyclobut- 1 -oxyi mino)acetamido]--3-[1 -methyl- 1 -pyrroli- diniu m)methyl]-3-cephem-4-carboxylate and 7-[2-(2-am inothiazol-4-yl)-(Z)-2-(1 -carboxycyclopent- 1 -oxyi m ino) acetamido]-3-[(1 -methyl- 1 -pyrro- lidinium)methyl]-3-cephem-4-carboxylate, respectively.

Claims

1. A compound of the formula

wherein R1 is hydrogen or a conventional amino-protecting group, and R2 is a straight or branched chain alkyl group containing from 1 to 4 carbon atoms, allyl, 2-butenyl or 3-butenyl or is a group

wherein R3 and R4 each are independently hydrogen, methyl or ethyl, or R3 and R4, taken together with the carbon atom to which they are attached, may be a cycloalkylidene ring containing from 3 to 5 carbon atoms, or a nontoxic pharmaceutically acceptable salt, physiologically hydrolyzable esters or solvate thereof.

2. The compound of Claim 1 which is 7-[(Z)-2-methoxyimino-2-(2-aminothiazol-4-yl)acetami- do]-3-[(1-methyl-1-pyrrolidinium)-methyl]-3-cephem-4-carboxylate, or a nontoxic pharmaceutically acceptable salt or solvate thereof.

3. The compound of Claim 1 which is 7-[(Z)-2-ethoxyimino-2.(2-aminothiazol-4-yl)acetami do]-3-(1-methyl-1-pyrrolidinium)-methyl]-3-cephem-4-carboxylate, or a nontoxic pharmaceutically acceptable salt or solvate thereof.

4. The compound of Claim 1 which is 7-[(Z)-2-(2-propoxyimino)-2-(2-aminothiazol-4-ylace- tamido]-3-(1 methyl 1 -methyl-1 -pyrrolidinium)methylj-3-cephem-4-carboxylate, or a nontoxic pharmaceuti- cally acceptable salt or solvate thereof.

5. The compound of Claim 1 which is 7-[(Z)-2-Allyloxyimino-2-(2-aminothiazol-4-yl)acetami- do]-3-(1-methyl-1-pyrrolidinium)methyl]-3-carphem-4-carboxylate, or a nontoxic pharmaceutically acceptable salt or solvate thereof.

6. A method of combatting bacterial infection in a warm-blooded mammal in need of such treatment comprising administering to said warm-blooded mammal an anti bacterially effective amount of at least one compound of Claim 1.

7. The method of Claim 6 wherein the compound of Claim 1 is7-[(Z)-2-methoxyimino-2-(2aminothiazol-4-ylacetamido]-3-[(1-methyl-1-pyrrolidinium)-methyl]-3-cephem-4-carboxylate or a nontoxic pharmaceutically acceptable salt or solvate thereof.

8. An antibacterial composition comprising an antibacterially effective amount of at least one compound of Claim 1 and an inert pharmaceutical carrier.

9. The composition of Claim 8 wherein the compound of Claim 1 is 7-[(Z)-2-methoxyimino2-(2-aminothiazol-4-yl)-acetamido]-3-[(1-methyl-1-pyrrolidinium)-3-cephem-4-carboxylate or a nontoxic pharmaceutically acceptable salt or solvate thereof.

10. An antibacterial composition in unit dosage form comprising from about 50 mg to about 1500 mg of at least one compound of Claim 1 and an inert pharmaceutical carrier.

11. The composition of Claim 10 wherein the compound of Claim 1 is 7-[(Z)-2-methoxyim ino-2-(2-am inothiazol-4-yl)-acetamido]-3-[(1 methyl 1 -pyrrolid i niu m)methyl-3-cephem-4-carboxylate or a nontoxic pharmaceutically acceptable salt or solvate thereof.

12. The compound of Claim 1 which is 7-[2-(2-aminothiazol-4-yl)-(Z)-2-(2-carboxyprop-2oxyimino)acetamido]-3-[(1-methyl-1-pyrrolidinium)-methyl]-3-cephem-4-carboxylate or a nontoxic pharmaceutically acceptable salt, physicologically hydrolyzable ester or solvate thereof.

13. A method of combatting Gram-negative bacterial infection in a warm-blooded mammal in need of such treatment comprising administering to said warm-blooded mammal an anti bacterially effective amount of at least one compound of Claim 1, wherein R1 is as defined in claim 1 and R3 and R4 each are independently hydrogen, methyl or ethyl, or R3 and R4, taken together with the carbon atom to which they are attached may be a cycloalkylidene ring containing from 3 to 5 carbon atoms or a nontoxic pharmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof.

14. The method of Claim 13 wherein the compound of Claim 1 is 7-[2-(2-aminothiazol-4-yl) (Z)-2-(2-carboxyprop-2-oxyi m ino)-acetamido]-3-[( methyl 1 -pyrrolid in iu m)methyl]-3-cephem-4carboxylate or a nontoxic pharmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof.

15. An antibacterial composition active against Gram-negative bacteria comprising an antibacterially effective amount of at least one compound of Claim 1 wherein R1 is as defined in claim 1 and R3 and R4 each are independently hydrogen, methyl or ethyl, or R3 and R4, taken together with the carbon atom to which they are attached may be a cycloalkylidene ring containing from 3 to 5 carbon atoms or a nontoxic pharmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof and an inert pharmaceutical carrier.

16. The composition of Claim 15 wherein the compound of Claim 1 is 7-[2-(2-aminothiazol 4-yl)-(Z)-2-(2-carboxyprop-2-oxyimino)acetamido]-3-[(1 -methyl-3-[(1 1-methyl- 1 -pyrrolidinium)me- thyl]-3-cephem-4-carboxylate or a nontoxic pharmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof.

17. An antibacterial composition active against Gram-negative bacteria in unit dosage form comprising from about 50 mg to about 1500 mg of at least one compound of Claim 1 wherein R' is as defined in claim 1 and R3 and R4 each are independently hydrogen, methyl or ethyl, or R3 and R4, taken together with the carbon atom to which they are attached may be a cycloalkylidene ring containing from 3 to 5 carbon atoms or a nontoxic pharmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof and an inert pharmaceutical carrier.

18. The composition of Claim 1 7 wherein the compound of Claim 1 is 7-[2-(2-aminothiazol 4-yl)-(Z)-2-(2-(2-carboxyprop-2-oxyim i no)acetamido-3-(( methyl 1 -pyrrol idiniu m)methyl]-3-ce- phem-4-carboxylate or a nontoxic phrmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof.

19. A process for the preparation of compounds of the formula

wherein R1 is hydrogen or a conventional amino-protecting group, and R2 is a straight or branched chain alkyl group containing from 1 to 4 carbon atoms, allyl, 2-butenyl or 3- butenyl, or is a group

wherein R3 and R4 each are independently hydrogen, methyl or ethyl, or R3 and R4, taken together with the carbon atom to which they are attached, may be a cycloalkylidene ring containing from 3 to 5 carbon atoms, or a nontoxic pharmaceutically acceptable salt, physiologically hydrolyzable esters or solvate thereof, which comprises acylating a compound of the formula

or an N-silyl derivative thereof, in which B' is hydrogen or a conventional-protecting group, with an acylating derivative of an acid of the formulae

wherein B2 is a conventional amino-protecting group, B3 is a conventional carboxyl-protecting group and R3 and R4 are as defined above, to produce a compound of the formulae

or

and subsequently removing all protecting group.

20. A process for the preparation of compounds of the formula

wherein R3 and R4 each are independently hydrogen, methyl or ethyl, or R3 and R4, taken together with the carbon atom to which they are attached, may be a cycoalkylidene ring containing from 3 to 5 carbon atoms, and nontoxic pharmaceutically acceptable salts, physiologically hydrolyzable esters and solvates thereof, which process comprises reacting a compound of the formulae

wherein R2, R3 and R4 are as defined above, B' and B3 are conventional carboxyl-protecting groups, B2 is a conventional amino-protecting group, with N-methylpyrrolidine to produce a compound of the formulae

and subsequently removing all protecting groups by conventional means.

21 The process of claim 19 or 20, for the preparation of 7-[2-(2-aminothiazol-4-yl)-(Z)-2-(2- carboxyprop-2-oxyimino)-acetamido]-3-[(1 methyl 1 -pyrrolid in ium)methyl]-3-cephem-4-carboxyl- ate (le) or a nontoxic pharmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof, which comprises reacting a mixture of benzhydryl 7-amino-3-chloromethyl-3cephem-4-caboxylate, (Z)-2-(2-t-butoxycabonylprop-2-oxyi m ino)-2(2-tritylam i noth iazol-4-yl) acetic acid, DCC, N-hydroxybenztriazole in an organic solvent to give benzhydryl 3-chloromethyl-7-[(Z) 2-(2-t-butoxycarbonylprop-2-oxyimino)-2-(2-tritylaminothiazol-4-yl)acetamido]-3-cephem-4-carboxylate (If) or alternatively reacting a mixture of benzhydryl 7-amino-3-chloromethyl-3-cephem4-carboxylate and bis(trimethylsilyl) acetamide with an acid chloride of (Z)-2-(2-t-butoxycarbonyl- prop-2-oxyimino)-2-(2-tritylaminothiazol-4-yl)acetic acid to give (If), then reacting (If) with iodide salt to give benzhydryl 7-[(Z)-2-(2-t-butoxycarbonyl prop-2-oxyim i no)-2-(2-trityla minothiazol-4-yl) acetamidoj-3-iodomethyl-3-cephem-4-carboxylate (Ig), then further reacting (lg) with N-methylpyrrolidine in an organic solvent to give (Ih), and finally deblocking (Ih) to give the title compound (le), melting at 160"C (dec) and/or if desired optionally converting (le) to its nontoxic pharmaceutically aceptable salts, physiologically hydrolyzable esters and solvates thereof.

22. The process of claim 19 of 20, for the preparation of compounds of the formula

wherein R' is hydrogen and R2 is methyl, ethyl, isopropyl, or allyl, or a nontoxic pharmaceutically acceptable salt or solvate thereof, which comprises reacting a mixture of benzhydryl 7 amino-3-chloromethyl-3-cephem.4-carboxylate and bis(trimethylsilyl) acetamide with an acid chloride of (Z)-2-methoxyimino-2-(2-tritylaminothiazol-4-yl) acetic acid or (Z)-2-ethoxyimino-2-(2tritylamino-thiazol-4-yl) acetic acid or (Z)-2-(2-propoxyimino)-2-(2-tritylamino-thiazol-4-yl)acetic acid or (Z)-2-allyloxyimino-2-(2-tritylaminothiazol-4-yl) acetic acid to give the corresponding condensed derivative containing 2-methoxyimino or 2-ethoxyimino or 2-propyoxyimino or 2nllyloxyimino group, then reacting said condensed derivative with iodide salt to give the v;;orresponding 3-iodomethyl derivative, then further reacting said 3-iodomethyl derivative with N-methyl-pyrrolidine in an organic solvent or a mixture of organic solvents to give the corresponding pyrrolidinium derivative and finally deblocking said pyrrolidinium derivative to give 7-[(Z)-2-methoxyimino-2-(2-aminothiazol-4-yl)acetamido]-3-[(1-methyl-1-pyrrolidinium)-methyl]-3-cephem-4-carboxylate, or 7-[(Z)-2-ethoxyimino-2-(2-aminothiazol-4-yl)acetamido]-3-[(1methyl-1-pyrrolidinium)-methyl]-3-cephem-4-carboxylate, or 7-[(2-propoxyimino)-2-(2-aminothiazol-4-yl)aceamido]-3-[(1-methyl-1-pyrrolidinium)methyl]-3-cephem-4-carboxylate, or 7-[(Z)-2-allyloxyimino-2-(2-aminothiazol-4-yl) acetamido]-3-[( 1 methyl1 -pyrrnlidinium)methyl]-3-cephem-4 carboxylate, and/or if desired converting said deblocked derivatives to nontoxic pharmaceuti- cally acceptable salt or solvate thereof.

23. A process as in claim 1 9 or 20, substantially as described in any of the foregoing Examples 1 to 8.

24. A compound according to claim 1, prepared by a process as in any of claims 19 to 23.