CA1130280A - Cephalosporin compounds - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Cephalosporin antibiotics of general formula (I) (wherein R and Rb, which may be the same or different, each represent a Clue alkyl group or Ra and Rb together with the carbon atom to which they are attached form a C3-7 cycloalkylidene group;
and R1 represents a C1-4 alkyl group) exhibit broad spectrum antibiotic activity with unusually high activity against strains of Psendomonas organisms as well as high activity against various members of the Enterobacteriaceae. The invention also includes the non-toxic salts and non-toxic metabolically labile esters of compounds of formula (I). Also described are compositions containing the antibiotics of the invention and processes for the preparation of the antibiotics.

Description

1~3~2~3~

- This invention is concerned with cephalosporin compounds possessing valuable antibiotic propert;es.
The cephalosporin compounds in this specification are named with reference to "cepham" after J-~Amer_Chem.
Soc., 1962, 84, 3400, the term "cephem" referring to the basic cepham structure with one double bond.
Cephalosporin antibiotics are widely used in the treatment of diseases caused by pathogen:ic bacteria in human beings and animals, and are especially useful in the treatment of diseases caused by bacteria which are resistant to other antibiotics such as penicillin com-- pounds, and in the treatment of penicillin-sensitive patients. In many instances it is desirable to employ a cephalosporin antibiotic which exhibits activity against both gram-positive and gram-negative microorganisms, and a significant amount of research has been directed to the development of various types of broad spectrum cephalosporin antibiotics.
Thus, for example, in our British Patent Specifica-tion No. 1,399,086, we describe a novel class of cephalo-sporin antibioticscontain ~g a 7~-(a-etherified oxyimino)-acylamido group, the oxyimino group having the ~y~ config-uration. This class of antibiotic rompounds is character-ised by high antibacterial activlty against a range of '~

., ~ . .

~3~28~ 2 gram-positive and gram-negative organisms coupleA with particularly high stability to ~-lactamases produced by various gram-negative organisms.
The discovery of this class of compounds has stimulated further research in the same area in attempts to find compounds which have improved properties, for example against particular classes of organisms especially gram-negative organisms.
In our British Patent Specification No. 1,496,757, we describe cephalosporin antibiotics containing a 7~-acylamido group of the formula R.C.CO.NH-RA (A) 0~ H2)m C (CH2)nCOOH
R
(wherein R is a thienyl or furyl group; RA and R may vary widely and may, for example, be Cl 4 alkyl groups or together with the carbon atom to which they are attached form a C3 7 cycloalkylidene group, and m and n are each O
- 20 or 1 such that the sum of m and n is O or 1), the compounds being Q isomers or mixtures of ~y~ and anti isomers containing at least 90% of the ~y~ isomer. The 3-position of the cephalosporin molecule may be unsub-stituted or may contain one of a wide variety of possib]e substituents These compounds have been found to have particularly good activity against gram-negative organisms.
Other compounds of similar structure have been developed from these compounds in further attempts to find antibiotics having improved broad spectrum antibiotic

2~3~

activity and/or high activity against gram-negative organisms. Such develop-ments have involved variations in not ~nly the 7~-acylamido group of formula (A) but also the introduction of particular groups in the 3-position of the cephalo sporin molecule.
mus, for example, South African Patent Specification 78/1870 dis-closes cephalosporin antibiotics wherein the 7~-acylamido side chain is inter alia a 2-(2-aminothiazol-4-yl)-2-(optionally substituted alkoxyimuno)-acetamido group and the 3-position may be substituted, for example, by the group -CH2Y in which Y represents the residue of a nucleophile, the Specification c~ntaining numerous examples of such nucleophiles, including nitrogen nucleophiles. The Specification contains, among numerous other examples, references to ocmpounds in which the above-mentioned optionally substituted alkoxyimino group is a carboxyalkoxyimino or carboxycycloaLkoxyimino group. South African Patent Specification 78/2168 discloses in broad terms sulphoxide compounds correspond-iny to the sulphides described in the last-mentioned Specification.
FurthermDre, Belgian Patent Specification No. 836,813 discloses oe phalosporin compounds wherein the group R in formula (A) above may be replaced by, for example, 2-aminothiazol-4-yl, and the oxyimino g~oup is a hydroxyimino or blocked hydroxyimino group, eOg. a methoxyim m o group. In such oompounds, the 3-position of the oephalosporin mDlecule is substituted by a methyl group which may itself be optionally substituted by any of , ~ . ,, .

3~

a large number of residues of nucleophilic compounds therein described. In the above-mentioned Specification no antibiotic activity is ascribed to such compounds which are only mentioned as intermediates for the preparation of antibiotics described in that Specification~

~36~:81 We have now discove~ed that by an appropriate selection of a small number of particular groups at the 7~-position in combination with a 3-alkyl-1,2,3-tri-azolium-l-ylmethyl group at the 3-position, cephalosporin compounds having particularly advantageous activity (described in more detail below) against a wide range of commonly encountered pathogenic organisms may be obtained.
The present invention provides cephalosporin anti-biotics of the general formula:

H H
S N
.CO,NH , ~ S
N Ra ~ -- N ~ C~l2N ~ N -O.C.COOH
Ib COO (I) (wherein R and R , which may be the same or different, each represent a Cl 4 alkyl group (preferably a straight chain alkyl group, i.e. a methyl, ethyl9 n-propyl or n-butyl group and particularly a methyl or ethyl group) or Ra and R together with the carbon atom to which they are attached form a C3 7 cycloalkylidene group, preferably a C3 5 cycloalkylidene group; and Rl represents a Cl 4 all;yl group, e.g. a methyl group)and non-toxic salts and non-toxic metabolically labile esters thereof.
The compounds according to the invention are syn isomers. The syn isomeric form is defined by the configuration of the group ~,~

.

lL3~;~ 80 ~ 6 --a . .1 .
OoC~COOH
Ib with respect to the carboxamido groupO In thls Speci~i-cation the ~ configuration is denoted structurally as \ - ~ C.CO.NH
N Ra \ o.c.COOH
Rb It will be understood that since ~he compounds according to the invention are geometric isomers, some admixture with the corresponding anti isomer may occur.
The invention also includes within its scope the solvates (especially the hydrates~ of the compounds of formula (I). It also includes within its scope salts of esters of compounds of formula (I)G
The compounds according to the present invPntion may exist in tautomeric forms (for example in respect of the 2-aminothiazolyl group) and it will be understood that such tautomeric forms, e.g. the 2-iminothiazolinyl form, are included within the scope of the inventionc Moreover, the compounds of ormula ~I) depicted above may also exist in alternative zwitterionic forms, for example wherein the

4-carboxyl group is pxotonated and the carboxyl group in the 7-side chain is deprotonated. These alternative forms, as well as mixtures of zwitterionic forms, are ~: .

~9~3~2~3 included within the scope of the present inventlon~
It will also be appreciated that when Ra and Rb in the above formula represent different Cl 4 alkyl ; groups, the carbon atom to which they are attached will comprise a centre of asymmetry. Such compounds are diastereoisomeric and the present invention embraces individual diastereoisomers of these compounds as well as mixtures thereof.
The compounds according to the invention exhibit broad spectrum antibiotic activity. Against gram-nega tive organisms the activlty is unusually high. This ,high - activity extends to many ~-lactamase-producing gram-negative strains. The compounds also possess high stability to ~-lactamases produced by a range of gram-negative and gram-positive organisms.
Compaunds according to the invention have been found to exhibit unusually high activity against strains of Pseudomonas organisms, e.g. strains of Pseudomonas aeru inosa as well as high activity against various members of the Enterobacteriaceae (e.g. strains of Escherichia coli, Klebsiella_pneumoniae, Salmonella typhimurium, Shigella sonnei, Enterobacter cloacae, Serratia marcescens, Providence species, Proteus mirabilis, and especially .. ..._ _ .
indole-positive Proteus organisms such as Proteus vulgaris and Proteus mor~anii) and strains of Haemophilus influenzae.
The antibiotic properties of the compounds accord-ing to the invention compare very favourably with those of ~ ~ 3~ ~ ~0 ~ 8 -the aminoglycosides such as amikacin or gentamicin. In particular, this applies to their activity against strains of various Pseudomonas organisms which are not susceptible to the majority of existing commercially available anti-biotic compounds. Unlike the aminoglycosides, cephalo-sporin antibiotics normally exhibit low toxicity in man.
The use of aminoglycosides in human therapy tends to be limited or complicated by the relatively high toxicity of these antibiotics. The cephalosporin antibiotics of the present invention thus possess potentially great advantages over the aminoglycosides.
Non-toxic salt derivatives which may be ormed by reaction o either or both of the carboxyl groups present in the compounds of general formula (I) include inorganic base salts such as alkali met~l salts ~e.g. sodium and potassium salts) and alkaline earth metal salts (e.g.
calcium salts); amino acid salts (e,g. lysine and arginine salts); organic base salts (e.g. procaine, phenylethylbenzylamine, dibenzylethylenediamine, ethanol-amine, diethanolamine and N-methylglycosamine salts).
Other non-toxic salt derivatives include acid addition salts, e.g. formed with hydrochloric, hydrobromicS
sulphuric, nitric, phosphoric, formiG and trifluoroacetic acids. The salts may also be in the form o resinates formed with, for example, a polystyrene resin or cross-linked polystyrene divinylbenzene copolymer resin con-taining amino or quaternary amino groups or sulphonic acid groups, or with a resin containing carboxyl groups, e.g. a polyacrylic acid resin. Soluble base salts (e~g.

' ~ :
, ~3~

alkali metal salts such as the sodium salt~ of compounds of formula (I~ may be used in therapeutic applications because of the rapid distribution o~ such salts in the body upon administration. Where, however, insoluble salts of compounds (I~ are desired in a particular appli-cation, e.g. for use in depot preparations, such salts may be formed in conventional manner, for example with appropriate organic amines.
These and other salt derivatives such as the salts with toluene-p~sulphonic and methanesulphonic acids may be employed as intermediates in the preparation and/or purification of the present compounds of formula (I), for example in the processes described below.
Non-toxic metabolically labile ester derivatives which may be formed by esterification of either or both carboxyl groups in the parent compound of formula (I) include acyloxyalkyl esters e.g. lower alkanoyloxy-methyl or -ethyl esters such as acetoxy-methyl or -ethyl or pivaloyloxymethyl esters. In addition to the above ester derivatives, the present invention inclu~es within its scope compounds of formula (I) in the form of other physiologically acceptable equivalents, i.e. physiologic-ally acceptable compounds which, like the metabolically labile esters are converted _ vivo into the parent anti-biotic compound of formula (I).
Preferred compounds accoxding to the presentinvention include those compounds of formula (I) wherein R represents a methyl group. Preference is also expressed for those compounds wherein Ra and Rb both repre-sent methyl groups or together with the carbon atom to ~13~3Z~3~ 10-which they are attached form a cyclobutylidene group.
Particularly preferred compounds according to the lnvention include the following compounds of formula (I) and their non toxic salts and non-toxic metabolically labile esters:-(~R,7R~7~E(Z~2-(2-~minothiazol-4-yl)-2~(2-carboxyprop-2-oxyimino)acetamido]-3-(3-methyl-1,2,3-triazolium l-yl)-methyl-ceph-3-em-4-carboxyl~te; and (6R,7R)-7-~(Z)-2-(2-aminothiazol-4-yl)-2-(1-carboxycyclobut-1-oxyimino)acetamido~-: 3-(3-methyl-172~3-triazolium-l-yl)methyl-ceph-3-em-4-carboxylate~ .
Other compounds according to the present invention include those for example wherein the groups Ra, Rb and are as follows:-Ra Rb . ' 1 --15 a) Alkyl roups b) .' (Ra _ ~ _ Rb~
cyclopropylidene ~CH3 cyclopentylidene -CH3 cyclopropylidene C2H5 cyclobutylidene C2H5 cyclopentylidene -C2H5 . . . . .

. .

~3~3Z1~9 The compounds of formula (I) may be used fox treat-ing a variety of diseases caused by pathogenic bacteria in human beings and animals, such as respiratory tract - infections and urinary tract infections.
According to another embodiment of the invention we provide a process for the preparation of an antibiotic compound of general formula (I) as hereinbefore defined or a non-toxic salt or non-toxic metabolically labile ester thereof which comprises (A) acylating a compound of the : 10 formula H H

o ~L CH211~N - Rl COO~ (II) [wherein R is as defined above; B is ~ S or : ~S ~3 O (a- or ~-); and the dotted line bridging the 2-, 3- and 4-positions indicates that the compound is a ceph-2-em or ceph 3~em compound] or a salt, e.g. an acid addi-tion salt (formed with, for example, a mineral acid such as hydrochloric, hydrobromic, sulphuric, nitric or phos-phoric acid or an organic acid such as methanesulphonic or toluene-p-sulphonic acid) or an N-silyl derivative thereof, or a corresponding compound having a group of formula ~ COOR at the 4-position [where R is a hydrogen atom or a carboxyl blocking group, e.g. the residue of an estex-forming aliphatic or araliphatic alcohol or an ~ ester-forming phenol, silanol or stannanol (the said alcohol, phenol, silanol or stannanol preferably '": , .

~3~32~

containing l--20 carbon atoms)] and having an associated anion A~
such as a halide, e.g. chloride or bromide, or trifluoroacetate anion, with an acid of formula S
\ / C.COOH (III) \ ~ 3 O.C.COOR
Rb (wherein Ra and Rb are as hereinbefore defined; R3 represents a carboxyl blocking group, e.g. as described for R2; and R4 is an amino or protected amino group~ or with an acylating agent corresponding khereto, (B) reacting a compound o~ Eormula ~ H H
S N
/ C.CO.NH ~ I ,~ B ~

O.C CoOR5a ~ N ~ 5 CH2X (IV) R COOR

(wherein Ra, Rb, R4, B and the dotted line are as hereinbefore defined; R5 and R5a may independently represent hydrogen or a carboxyl blocklng group; and X is a replaceable residue of a nucleophile (leaving group), e.g. an acetoxy or dichloroacetoxy group or a halogen atom such as chlorine, bromine ~ 12~

2 ~

or iodine) or a salt thereof, with a compound of the formula ~N\
N N - R
~=~J (V).
: 5 (wherein R is as defined above);
or (C) alkylating a compound of the ormu1a I . . .
H H
S C.CO.NU -- I ~ B N
\ 1 5a ~ CH2N ~ N
O.C.COOR COOR
.,: I
Rb (VI) (wherein Ra, R~, ~4, B and the dotted line are as herein-before defined; and R5 and R5a both represent carbox~l blocking groups) with an alkylating agent serving to introduce the Rl su~stituent into the above triazole ring in formula (VI);
whereafter, if necessary and/or desired in each instance, any of the following reactions, in any appropriate sequence, are carried out:-i) conversion of a ~-isomer into the desired ~3-isomer, ii) reduction of a compound wherein B is ~S-~ O to ~.
. .

3~ Z ~ ~

form a compound whérein B ls ~S9 iii) conversion of a carboxyl group into a non-~oxic salt or non-toxic metabolically labile ester function, and iv) removal of any carboxyl blocking and/or N~
protecting groups.
In the above-described process ~A), the starting material of formula (II) i~ pref~rably a compound wherein the dotted line represents a ceph~3-em compound.
Acylating agents whLch may be employed in the preparation of compounds of formula (I) include acid halides, particularly acld chlorides or bromides. Such acylating agents may be prepared by reacting an acid (III) or a salt thereof with a halogenating a8ent e.g. phos-phorus pentachLoride, thionyl chloride or oxalyl chloride.
Acylations employing acid halides may be effected in aqueous and non-aqueous reaction media, conveniently at temperatures of from -50 to ~50C, preerably -20 to +30C, if desired in the presence of an acid binding agent. Suitable reaction media include aqueous keto~es such as aqueous acetone, esters such as ethyl acetate, halogenated hydrocarbons such as methylene chloride, amides such as dimethylacetamide, nitriles such as acetonitrile, or mixtures of two or more such solvents.
Suitable acid binding agents include tertiary amines (e.g.
triethylamine or dimethylaniline), inorganîc bases (e~g.
calcium carbonate or sodium bicarbonate)~ and oxiranes such as lower 1~2-alkylene oxides ~e.g. ethylene oxide or . ~
- . ~

~3~2~3 propylene oxide) which bind hydrogen halide liberated in the acyla~ion reaction.
Acids of formula (III) may themselves be used as acylating agents in the preparation of compounds of formula (I). Acylations employing acids (III) are desir-ably conducted in the presence of a condensing agent, for example a carbodiimide such as N,N~dicyclohexylcarbodi-imide or N-ethyl-N'-y-dimethylaminopropylcarbodiimide; a carbonyl compound such as carbonyldiimidazole; or an isoxazolium salt such as N-ethyl-5-phenylisoxazolium perchlorate.
Acylation may also be effected with other amide~
forming derivatives of acids of formula (III) such as, for example, an activated ester, a symmetrical anhydride or a mixed anhydrîde (e.g. formed with pivalic acid or with a haloformate, such as a lower alkylhalo~ormate). Mixed anhydrides may also be formed with phosphorus acids (for example phosphoric or phosphorous acids), sulphuric acid or aliphatic or aromatic sulphonic acids (for example toluene-~-sulphonic acid). An activated ester may con-veniently be formed in situ using, for example, l-hydroxy-- benzotriazole in the presence of a condensing agent as set out above. Alternatively, the activated ester may be preformed.
Acylation reactions involving the free acids or their above-mentioned amide-forming derivatives are desirably effected in an anhydrous reaction medium, e.g.`
methylene chloride, tetrahydrofuran, dimethylformamide or acetonitrile.

3~ 3~

.

If desired, the above acylation reactions may be carried out in the presence of a catalyst such as 4-di-methylaminopyridine The acids of formula (III) ~nd acylating agents corresponding thereto may9 if desired, be prepared and employed in the form of their acid addition salts. Thus, for example, acid chlorides may conveniently be employed as their hydrochloride salts, and acid bromides as their hydrobromide salts.
The compound of formula ~V) may act as a nucleophile to displace a wide variety of su~stituents X
from the cephalosporin of formula (IV). To some extent the facility of the displacement is related to the PKa of the acid HX from which the substituent is derived~
Thus atoms or groups X derived from strong acids tend9 in geheral, to be more easlly displaced than atoms or groups derived from weaker acids. The facllity of the dis-placement is also related, to some extent, to the precise identity of the alkyl group in the compound of formula (V~.
The displacement of X by the compound of formula (V) may conveniently be effected by maintaining the reactants in solution or suspension. The reaction is advantageously effected using from 1 to 20, preferably 1 to 4, moles of the compound ~V).
Nucleophilic displacement reactions may con~en-- iently be carried out on those compounds of formula (lV) wherein the substituent X is a halogen atom or an acyloxy group for example as discussed below.

. . ~ . -- 17 - ~ ~3~%~

Compounds of formula tIV) wherein X is an acetoxy group are convenient starting materials for use in the nucleophilic displacement reaction with the compound of formula (V~. Alternative starting materials in this class include compounds of formula (IV) in which X is the residue of a substituted acetic acid e.gO chloroacetic acid, dichloroacetic acid and trifluoroacetic acid.
Displacement reactions on compounds (IV) possessing X substituents of this class, particularly ln the case where X is an acetoxy group, may be facilitated by t~e presence in the reaction medium of iodide or thiocyanate ions.
The substituent X may also be derived from formic acid, a haloormic acid such as chloroformic acid, or a carbamic acid.
When using a compound of formula (IV) in which X
represents an.acetoxy or substituted acetoxy group, it is generally desirable that the group R5 in formula (IV) should be a hydrogen atom and that B should represent >S.
In this case, the reaction is advantageously effected in an aqueous medium, preferably at a pH of 5 to 8, particu-larly 5.5 to 7.
The above-described process employing compounds of formula (IV) in which X is the residue of a swbstituted acetic acid may be carried out as described in British Patent Specification No. 1,241,657.

Z~

When using compounds of formula (IV) in which X is an acetoxy group, the reaction is conveniently effected at a temperature of 30~ to llO~C, preferably 50- to 80C.
Halo~ens Compounds of formula (IV) in which X is a chlorine3 bromine or iodine atom can al50 be conveniently used as starting materials in the nucleophilic displacement reac-tion with the comp~nd offormula (V). When using compounds of formula (IV) in this class, B may represent~ S-~3 0 and R may represent a carboxyl blocking groupO The reaction is conveniently effected in a non-aqueous medium which preferably comprises one or more organic solvents, advantageously of a polar nature, such as ethers, e.g.
dioxan or tetrahydrofuran, esters, e.g. ethyl acetate, amides, e~g. formamide and N,N-dimethylformamide, and ketones, e.g. acetone. Other suitable organic solvents are described in more detail in British Patent Speciflcation No. 1,326,531. The reaction medium should be neither extremely acidic nor extremely basic. In the case of reactions carried out on compounds of ~ormula (IV) in which R5 and R5a are carboxyl blocking groups the 3- (3-alkyl-1,2,3-triazolium)-methyl product will be formed as the corresp~nding halide salt which may, if desired, be subjected to one or more ion exchange reactions to ob~ain a salt having the desired anion~
When using compounds of formula (IV) in which X is a halogen atom as described above, the reactlon is conveniently effected at a temperature of -10 to +50C, .~ .
~ .

' ~3~2~3~ 19 preferably ~10 to ~30C~
In pro~ess (C) above, the triaæolylmethyl compound of formula (VI) i5 advantageously reacted with a Cl 4 alkylating agent of the formula RlY wherein ~ is as defined above and Y is a leaving group such as a halogen atom (e.g. iodine, chlorine or bromine) or a hydrocarbyl~
sulphonate (e~g. mesylate or tosylate) group, or ~ Y
represents dimethyl sulphate. The alkylation reaction is preferably carried out at a temperature in the range of 0 to 60C, advantageously 20 to 30C. The reaction may be conveniently effected in an inert solvent such as an ether e.g. tetrahydrofuran, an amide, e.g. dimethylformamide, or a halogenated hydrocarbon, e.g. dichloromethane. Alter-natively, where the alkylating agent is liquid under the reaction conditions, this agent can itself serve as a solvent.
The compound of formula (VI) used as starting material in process (C) may be prepared for example by reaction of a compound of formula (IV) (as defined above) with a triazole of formula N NH (VII) in an analogous manner to the nucleophilic displacement reaction described with respect to process (B)~ This reaction is preferably carried out in the presence of an acid scavenging agent. The triazole itself may act as an acid scavenging agent.
rhe reaction product may be separated from the ~L~ 3~ 2 ~ 20 -reaction mixture, which may contain9 for example9 un-changed cephalosporin starting material and other sub-stances, by a variety of processes including recrystallisa-tion, ionophoresis, column chromatography and use of ion-exchangers (for example by chromatography on ion-exchange resins) or macroreticular resins.
L~-Cephalosporin ester derivatives obtained in accordance with the process of the invention may be con-verted into the corresponding L~3-derivative by, for example, treatment of the L~ -ester with a ba~e such as pyridine or triethylamine.
A ceph~2-em reaction product may also be oxidised to yield the corresponding ceph-3-em l~oxide, ~or example by reaction with a peracid, e.g. peracetic or m-chloro-perbenzoic acid; the resulting sulphoxide may, ifdesired, subsequently be reduced as described hereinafter to yield the corresponding ceph-3-em sulphide~
Where a compound is obtained in which B is ~S -~ O
th;s may be converted to the corresponding sulphide by, for example, reduction of the corresponding acyloxy-sulphonium or alkoxysulphonium salt prepared in situ by reaction with e.g. acetyl chloride in the case of an acetoxysulphonium salt, reduction being effected by, for example, sodium dithionite or by iodide ion as in a solution of potassium iodide in a water-miscible solvent e.g. acetic acid, acetone, tetrahydrofuran, dioxan, di-- methylformamide or dimethylacetamide. The reaction may i~ be effected at a temperature of from -20- to +50C.
Metabolically lab;le ester derivatives of the 1 ~ 3~ 2 ~ Q 21 ~

compounds of formula (I~ may be prepared by reacting a compound of formula (I) or a salt or protected derivative thereof with an appropriate ~sterifying agent such as an acyloxyalkyl halide (e.g. iodide) conveniently in an inert organic solvent such as dimethylformamide or acetone, followed, where ne~essary, by removal of any protecting groups.
Base salts of the compounds of formula (I) may be formed by reacting an acid of formula (I) with the appropriate base. Thus, for example, sodium or potassium salts may be prepared using the respective 2-ethyl-hexanoate or hydrogen carbonate salt. Acid addition salts may be prepared by reacting a compound of Eormula (I) or a metabolically labile ester derivative thereof with the appropriate acid.
Where a compound of formula (I) is obtained as a mixture of isomers, the ~y~ isomer may be obtained by, for example, conventional methods such as crystallisation or chromatography.
For use as starting materials for the preparation of compounds of general formula (I) according to the invention, compounds of general formula (III) and acid halides and anhydrides corresponding thereto in their svn isomeric form or in the orm of mixtures of the ~y~
isomers and the corresponding anti isomers containing at least 90% of the syn isomer are preferably used.
Acids of formula (III) (provided that Ra and Rb together with the carbon atom to which they are attached do not form a cyclopropylidene group) may be prepared by ,~ .

~L3~2 etherification of a compou~d of ormu1a S N
~ .COOR6 (VIII) N
OH
(wherein R4 is as hereinbefore defined and R6 represents a carboxyl blocking group), by reaction with a compound o general formula Ra T.C.COOR (IX) Ib (wherein Ra, Rb and R3 are as hereinbefore defined and T is halogen such as chloro, bromo or iodo; sulphate; or sulphonate such as tosylate), followed by removal of the carboxyl blocking group R6. Separation of isomers may be effected either before or after such etherification. The etherification reaction is generally carried out in the presence of a base, e.g. potassium carbonate or sodium hydride, and is preferably conducted in an organic solvent, Eor example dimethylsulphoxide, a cyclic ether such as tetrahydrofuran or dioxan, or an N,N-disubstituted amide such as dirnethylormamide. Under these conditions the configuration of the oxyimino group is substantially unchanged by the etherification reaction. The reaction should be effected in the presence of a base if an acid addition salt of a compound of formula (VIII) is used.

. . .

3~;2843 -The base should be used in sufflclerlt qu~ntity to neutral~
ise rapidly the ~cid in question.
Aclds of general formula (III) may also be prepared by reaction of a compound of ormula ,b S N
-- CO. COOE~6 (X) (wherein R4 and R are as hereinbefore defined) with a compound of formula ~a H2N.o.C.CooR3 (XI) Rb (wherein R~, Rb and R3 are as defined above), Eollowed by removal o the carboxyl blocking group R , and where necessary by the separation of sy_ and anti isomers.
The last-mentioned reaction is particularly applic-able to the preparation of acids of form~tla (III) wherein ; Ra and Rb together with the carbon atom to which they are attached form a cyclopropylidene group. In this case, the relevant compounds of formula (XI) may be prepared in conventional manner, e.g. by means of the synthesis described in Belgian PatentSpecification No. 866,422 for the preparation of t-butyl l-amino-oxyc~clopropane carboxylate.
The acids of form~tla (III) may be converted to the corresponding acid halides and anhydrides and acid addi-tion salts by conventional methods, for example as described hereinaboveO

- 2 4~

Where X is a halogen ~iOe~ chlorlne9 bromine or iodine) atom in formula ~IV), ceph-3~em starting compounds may be prepared in ~onventional mann~er, e.g. by halogena-tion of a 7~-protected amino-3-methylceph-3-em-4-carboxy~
acid ester l~-oxide, removal of the 7~-protecting group, acylation of the resulting 7~am1no compound to form the desired 7~-acylamido group, e.gO in an analogous manner to process (A) above, followed ~y reduction of the l~oxide group later in the sequence~ This is described in 10 British Patent No. 1,326,531. The corresponding ceph-2-em compounds may be prepared by the method of Dutch - published Patent Application No. 6,902,013 by reaction of a 3-methylceph-2-em compound with N-bromosuccinimide to yield the corresponding 3-bromomethylceph-2-em compound.
Where X ln formula (IV) is an aceto~y group, such starting materials may be prepared for example by acyla-tion o~ 7-aminocephalosporanic acid, e.g. in an analogous manner to process (A) above. Compounds of ~ormula (IV) in which X represents other acyloxy groups can be prepared by acylation of the corresponding 3~hydroxy-methyl compounds which may be prepared for example by hydrolysis of the appropriate 3-acetoxymethyl compounds, e.g. as described in British Patent Specifications Nos.
1,474,519 and 1,531,212.
The starting materials of formula (II) are new compounds. These compounds m~y be prepared in convent-ional manner9 for example, by nucleophilic displacement of the corresponding 3-acetoxymethyl compound with the appropriate nucleophile.
A further method for the preparation of the ~3~ Q

starting materials of formula ~II) comprises deprotecting a corresponding protected 7~-amino compound in conven tional manner e.g. using PC15~
It should be appreciat~d that in some of the above transformations it may be necessary to protect any sensitive groups in the molecule of the compound in question to avoid undesirable side reactions~ For example, during any of the reaction sequences referred to above it may be necessary to protect the NH2 group of the aminothiazolyl moiety, for example by tritylation, acylation (e.g. chloroacetylation), protonation or other conventional method. The protecting group may there-after be removed in any convenient way which does not cause breakdown of the desired compound, e.g. in the case of a trityl group by using an optionally halogenated carboxylic acid, e.g. acetic acid, ormic acid, chloro-acetic acid or tri1uoroacetic acid or using a mineral acid, e.g. hydrochloric acid or mixtures of such acids~
preferably in the presence of a protic solvent such as water or, in the case of a chloroacetyl group, by treat-- ment with thiourea.
Carboxyl blocking groups used in the preparation of compounds of formula (I) or in the preparatlon of necessary starting materials are desirably groups which may readily be split off at a suitable stage in the reaction sequence, conveniently at the last stage. It may, however, be convenient in some instances to employ non-toxic metabolically labile carboxyl blocking groups such as acyloxy-methyl or -ethyl groups (e.g. acetoxy-.

~L3~Z~O

methyl or -ethyl or pivaloyloxymethyl) and retain these in the final product to give an approprlate ester derivative o~ a compound of formula (I)~
Suitable carboxyl blocking groups are well kno~n in the art 3 a list of representative blocked carboxyl groups being included in British Patent No. 1,399,086.
Preferred blocked carboxyl groups include aryl lower alkoxycarbonyl groups such as p~methoxybenzyloxycarbonyl, ~-nitrobenzylo~ycarbonyl and diphenylmethoxycarbonyl;
lower alkoxycarbonyl groups such as t-butoxycarbonyl; and lower haloalkoxycarbonyl groups such as 2,2,2-trichloro-ethoxycarbonyl. Carboxyl blocking group(s) may subsequently be removed by any of the appropriate methods disclosed in the literature~ thus, ~or example, acid or base catalysed hydrolysis is applicable in many cases, as are enzymically-catalysecl hydrolyses.
The follow~ng Examples illustrate the invention.
All temperatures are in C. 'Petrol' means petroleum ether (b.p. 40-60).
T.l.c is thin-layer chromatography using pre-coated plates (Merck F254,0.25 mm thick coating) which were examined under ultra-violet light at 254 nm and were developed with iodine .
Proton magnetic resonance (p.mOr.) spectra are inserted where appropriate and were determined at 100 MHz.
The integrals are in agreement with the assignments, coupling constants, J, are in Hz, the signs not being determined; s = singlet 9 d = doublet, dd = dou~le doublet, m = multiplet and ABq = AB quartet. 0 Preparation 1 imino?acet _e To a stirred and ice-cooled solution of ethyl 3~

acetoacetate (292 g) in glacial acetic acid ~296 ml) was added a solution of sodium nitrite (180 g) in water (400 ml) at such a rate that the reaction temperature was malntained below 10C. Stirring ancl cooling were continued for about 30 min., when a solution of potassium chloride (160 g) in water (800 ml) was added. The resu~-ing mixture was stirred for one hour. The lower oily phase was separated and the aqueous phase was extracted with diethyl ether. The extract was combined with the oil, washed successively with water and saturated brine, dried, and evaporated. The residual oil, which solidif~d on standing, was washed with petrol and dried in vacuo over potassium hydroxide, giving ethyl (Z)-2-(hydroxy-imlno)-3-oxobutyrate (309 g).
A stirred and ice-cooled solution of ethyl (Z)-2-(hydroxyimino)-3-oxobutyrate (150 g) in dlchloromethane (400 ml) was treated dropwise wlth sulphuryl chloride (140 g). The resulting solution was kept at room temp-erature for 3 days~ then evaporated. The residue was dissolved in diethyl ether, washed with water until the washings were almost neutral, dried, and evaporated. The residual oil (177 g~ was dissolved in ethanol (500 ml) and dimethylaniline (77 ml~ and thiourea (42 g) was added with stirring. After two hours, the mixture was Eiltered and the residue washed with ethanol and dried to give the title compound (73 g); m.p. 188 (decornp.).
Preparation 2 Ethyl (Z)-2-hydroxyi no-2-(2-tritylaminothiazol-4-yl) acetate, hydrochloride Trityl chloride (16.75 g) was added portionwise over 2 hours to a stirred and cooled (-30) solution of , 3~

the product of Prep~ra~ion 1 (12.91 ~) and triethylamine (8.4 ml) in dimethylformamide (28 ml). The mixture was allowed to warm to 15~ over one hour9 stirred for a further 2 hours and then partltioned between water (500

5 ml) and ethyl acetate (500 ml)O The organic phase was separated, washed with water (2 x 500 ml) and then shaken with lN HCl (500 ml). The prec~pitate was collected, washed successively with water (100 ml), ethyl`
acetate (200 ml) and ether ~200 ml~ and dried in vacuo to provide the title com~_nd a3 a white solid ~16.4 g);
m.p. 184 to 186a (decomp.)O
Preparation 3 ~ -(2-.` tritylaminothiazol-4-yl~ace-tat-e Potassium carbonate (34~6 g) and t-butyl 2-bromo-2-methylpropionate (24.5 g) were added to a stirred solu-tion under nitrogen of the product of Preparation 2 (49.4 g) in dimethylsulphoxide (200 ml) and the mixture was stirred at room temperature for 6 hours. The mixture - 20 was poured into water (2 1)7 stirred for lO mins.~ and filtered. The solid was washed with water and dissolved in ethyl acetate (600 ml)~ The solution was washed successively with water, 2N hydrochloric acid, water, and saturated brine, dried9 and evaporated. The residue was recrystallised from petrol to give the title compound (34 g~ m.p. 123c5 to 125-.

3~

Preparati~n 4 (Z)-2-(2-t-Butoxycarbonylprop-2-oxyimino)~2-~2-trityl-The product of Preparation 3 ~2 g) was dissolved in methanol (20 ml~ and 2N sodium hydroxide (3.3 ml) was added. The mixture was refluxed for 1.5 hours and then concentrated. The residue was taken up in a mixture of water (50 ml), 2N hydrochloric acid (7 ml), and ethyl acetate (50 ml). The organic phase was separated, and the aqueous phase extracted with ethyl acetate. The organic solutions were combined, washed successively with water and saturated brine, dried and evaporated. The residue was recrystallised from a mixture of carbon tetrachloride and petrol to give the tLtle campound (1 g), m~p. 152 to 156 (decomp.).
Preparation 5 Ethyl (Z)-2-(2-trit~laminothiazol-4-yl)-2-(1-t-butoxy-carbonylcyclobu ~
The product of Preparation 2 (55.8 g) was stirred under nitrogen in dirnethylsulphoxide (400 ml) with potassium carbonate (finely ground, 31~2 g) at room temperature. After 30 minutes, t-butyl l-bromocyclo-butanecarboxylate (29.2 g) was added. After 8 hours further potassium carbonate (31.2 g) was added. More potassium carbonate (6 x 16 g portions) was added during the next three days and further t-butyl l-brornocyclo-butanecarboxylate (3045 g3 was added after 3 days. After 4 days in all, the mixture was poured into ice-water (caO
3 litres) and the solid was collected by filtration and 3~3~
_ 30 _ washed well with water and petrol. The solid was dissolved in ethyl acetate and the solution washed with' brine (twice), dried with magnesium sulphate and evapor-ated to a foam. This foam was dissolved in ethyl acetate-petrol (1:2) and filtered through s;lica gel (500 g).
Evaporation gave the title compound (60 g) as a yellow foam, ~ (CHBr3) 3400 (NH~ ar.~ 1730 cm (ester).
Preparation 6 (Z)-2-(1-t-But~ _ r _ lobut-l-oxy_mino)-2-(2-trityl-aminothiazol-4-yl) acetic acid A mixture of the product of Preparation 5 (3.2 g) and potassium carbonate (1.65 g) was refluxed in methanol (180 ml) and water (20 ml) for 9 hours and the mixture was cooled to room temperature. The mixture was concen-trated and the residue partitioned between eth~l acetateand water, to which was added 2N HCl (1202 ml). The organic phase''was separated and the aqueous phase extracted with ethyl acetate. The combined organic extracts were washed with saturated brine, dried and evaporated to give the title compound (2.3 g); AmaX
(ethanol) 265 nm (ElCvm243).

3l Example 1 a) Diphenylmethyl (lS.6R,7R)-3-Bromomethyl-7-r(Z~-2-(2-t-butoxycarbonyl-prop-2-oxyimino~-2~2-tritylaminothiaæol-4-yl)acetamidolceph-3-em-4-carboxylate2 l~Oxide A solution of the product of Preparatior-~ 4 (0.526g) in dry tetrahydrofuran ~6 ml) was treated successively with l-hydroxybenztriazole monohydrate (0.141 g) and N,N'-dicyclohexylcarbodiimide (0.198 g) in tetra-hydrofuran (4 ml). The developing suspension was stirred for 30 minutes at 23 and then filtered. A
solution of diphenylmethyl (lS,6R,7R)-7-amino-3-bromo-methylceph-3-em-4-carboxylate, l-oxide (0.427 g) in dichloromethane (260 ml) was treated at 23 with the ; above Eiltrate. The solution was stirred ~or 18 hours at 20 to 25, evaporated to dryness, then the residue was dissolvèd :Ln dichloromethane and washed successi.vely with saturated aqueous sodium bicarbonate, water and brine, then dried and evaporated in vacuo to a foam (l.Ol g).
This foam was purified by chromatography on preparative silica plates using toluene:ethyl acetate:
acetic acid = 190:50:2.5 as eluant. The purified product was isolated as a foam which was dissolved in ethyl acetate (5 ml) and precipitated from petrol (200 ml~ to give the title compo~md (0.69 g) as a ; maxl/EtOH) 268 nm (El/ 182) with a inflection at 242 nm (ElCm 230), vmax (Nujol) 3375 (NH), 1805 (~-lactam~, 1730(CO2R) and 1688 and 1515 cm (CONH).
~;'' : ' . .
' ~

3~

b~ L~ L~

cetami ~ 4-carboxylate, l-oxide romide salt A mixture of diphenylmethyl ~lS, 6R~ 7~-3-bromome~hyl-7-[(Z)-2-(2-t~butoxycarbonylprop-2 oxyimino)-2-(2-tri~ylaminothiazol--4-yl)acetamido~ceph-3-em-4-carboxylate, l-oxide (1~05 g) and 1-methyl-1,2,3-triazole (l.l9 g) in tetrahydrofuran (15 ml) was stirred at 22 to 30 Eor 4.7 days in the absence of light. The mixt~re was evaporated and the residue triturated with ether and ethyl acetate to ~ give the title com~ound (1 g) as a solid; ~inflec~ion l~ (CHC13) 267 nm (ElCm 155 E 17,300) and ~m x (Nujo ~ 3600 to 2500 (NH and water), 1798 (~-lactam, 1725 ~C02R) and 1678 15 and 1515 cm 1 (CONH).
c) DiphenylmethYl (6R,7R)-3-(3-methyl-1,2,3-triazolium-l-yl)methyl-7- ~Z)-2-(2-t-butoxycarbonylprop-2-oxyimino)-2-(2-tritylaminothiazol-4-yl)acetamid~lceph 3-em-4-carboxylateL
Bromide and Iodide salts The product of stage b) (0.8 g) in acetone ~5 ml) at -10 was treated with potassium iodide (0~427 g) and stirred for 10 minutes.
A further portion of potassium iodide (0.427 g) and æetyl chloride (0.11 ml) was added and the mixture was stirred vigorously at ~10 to 0 over 30 minutes. The mixture was added dropwise to a solution of sodium metabi-sulphite (0.35 g) in water (20 ml) to give a gummy solid.
The mixture was extracted with dichloromethane and brine and the organic phase wa~ washed with brine then dried and Pvaporated to a foam (t.l.c. indicated some unchanged starting material).
I ra~le nlal k .

The above reduction sequence using potassium iodide and acetyl chloride was repeated exactly as described above to give the title compound (0.6 g)g mainly as the iodide salt, t.l~c., Rf 007 (chloroform:met'hanol:acetic acid =
90:16:20), ~ (DMS0-d ) 1.08 and 1.15 t2s, triaæole 4 and 5-H), 3.22 (s, thiazol-5-yl proton), 4.03 (dd, J 9 and 5H
7-H)9 5.70 (s, NMe), and 8.60 ~broad s, CMe2 and t butyl).
d) (6R,7R)-7-r(Z~-2-(Aminothiazo 10 methylceph-3-Pm-4-carboxyla~e The product of stage c) (1.72 g) was suspended in a mixture of anisole (1.7 ml) and tri1uoroacetic acid (7 ml) at 22 for 1 minute. The mixture was evaporated in vacuo to an oil which was then azeotroped with toluene. The toluene was removed in ,vacuo and the resulting oil triturated with ether to give a solid (lo 3 g)~
A suspension oE the above s~lid in anisole (1.3 ml) and trifluoroacetic acid (15 ml) was stirred for 15 minutes.
The supernatant liquid was decanted off and the solid was washed with trifluoroacetic acid (10 ml). The combined trifluoroacetic acid solutions were concentrated in vacuo to an oil which,on trituration with ether gave a solid (0.9 g).
~, A portion (0.85 g) of this solid was stirred for 10 minutes with a mixture of trifluoroacetic acid (4 ml) and water (150 ml) and the mixture was successively extracted with ethyl acetate and et'her. The aqueous layer was freeze~
dried to give the title compound (0.75 g) as a solid associated with 1.3 moles of trifluoroacetic ac d [a~D -17,9 (c 0.56, DMS0), Ai (pH 6 phosphate~ 235 nm (ElCm24) with further inflections at 255 nm (El/a207) and 300 nm ~E182)~

~ 34 ~ ` . , a) (l-t-butoxycarbonylcvclobut-l-oxyimlno ~ r ~Yi~ 8_1g~
A stirred solution of the product of Preparation 6 (1.167 g) in tetrahydrofuran (15 ml) was treated successively with l-hydroxybenztriazole hydrate (0.337 g) and N,N'-dicyclohexylcarbodlimide ~0.495 g) for 30 minutes at 22.
Filtration afforded a solution of the activated es~er which was added to a solution of dlphenylmet~hyl (lS,6R,7R)-7-amino-3-bromomethylceph-3-em-4-carboxylate l-oxide (0.95 g~ in dichloromethane (550 ml). The solution was stirred for 16 hours then evaporated to dryness. A solution of the residue in dich.loromethane was wa~hed successlvely with aqueous sodium bicarbonate9 and brine, and then dried and evaporated to a foam (2.2 g) which was purified by preparative thin-layer chromato-graphy (using toluene:ethyl acetate:acetic acid - 40:10:1 for development) to give the title ~ (1.4 g) with (EtOH) 266 nm (El% 192) and an inflection at max ,~, lcm ( lcm 224), ~max (Nujol) 3360 (N~) 1805 (~-lactam), 1730 (CO2R) and 1689 and 1520 cm (CONH).
b) Diphenylmethyl (lS,6R17R)-3-(3-methyl-1,2~3-triazolium -l-yl) met~y~-7-r(Z)-2~ t_b~y~g3~g~l~ssy~L __ut-l-ox~imino1-2-(2-telcvlaminothiazol~4-yl)acetamido~ce~h-3-em-4-carboxylate, l-oxide? Bromide Salt A mixture of diphenylmethyl (lS,6R,7R)-3-bromomethyl-~L~3~121 7-[(Z)-2-(1-t-butoxycarbonylcyclobut-l~oxyimino)~2-(2-trityl3minothia~ol-4~yl)~ceta~ido~ceph~3~em-4~
carboxylate~ l-oxide (1.04 g) and 1-methyl-1,2,3 triazole (1.240 g) in tetrahydrofuran (8 ml) was stirred at ca 21 for 50 hours.
The solution was evaporated to an oil which~ on leaching several times with ether gave the title ~
(0.910 g) as an amorphoU~ solid [a]D5-2 (_ ~.9, DMS0), Ainfl(EtoH) 243 nm (ElCm207, ~23,270) with ~urther inflections at 265 nm (ElCml70, el9,110), and 310 nm (ElCm50~ e5,620) and AmaX390 nm (ElCm31, ~3,4853.
c~ ~1:~:~ '' l-yl) methyl-7-~(Z?-2-(l-t-butoxycarbony~cyclobut-l-oxyimin -2~(2~tritylarnlno~hlazol-4~ 2~eetami~o~ceph~3~em-4-carboxylate, Iodide _alt Potassiurn iodide (0.481 g) w~s added to a cooled (-10~ mixture of the product of stage b~ (0.816 g) and the mixture was stirred for 10 minutes at -10. A further portion of potassium iodide (0.481 g) was added, followed by acetyl chloride (0.12 ml) and the resulting suspension stirred for 30 minutes at -10 to 0. The mixtuxe was poured into a stirred solution of sodium metabisulphite (0.36 g) in water (20 ml~ and the gummy solid extracted with dichloromethane. The organic layer was washed with brine, dried and evaporated to a foam (t.l.c. indicated some starting material~.
The above produc~ was sub~ec~ed to a similar reduction sequence ~using potassium iodide and acetyl chloride as described above~ to give the title ~

' ' ~0.713 g) as a foam, t.l.c. RfO.45 (chloroform:methanol:
acetic acid - 90:16:20), and ~(D~SO-d ) 1.06 and 1.12 (2s, triazole 4 and 5-H), 3.22 (s, thiazol-5-yl proton), 4.05 (dd, J 9 and 5Hz, 7-H), 5.70 (s, NMe)~ 7.2 to 7.8 (m,cyclo-but-2-yl protons) and 708 to 8.4 (m, cyclobut-3-yl protons~.
d) The product of stage c) ~0.65 g) in anisole (0.6 ml) and trifluoroacetic acid (2.4 ml) was stirred at 20 for 1 minute and concentrated in vacuo to give an oil.
Trituration of this oil with ether gave a powder which was treated with anisole (0.6 ml) and trifluoroacetic acid (12 ml). After stirring for 15 minutes the solutlon was decanted to leave a black amorphous paste which was leached with trifluoroacetic acid.
The combined trifluoroacetic acid solutions were concentrated in vacuo to an oil which, on treatment with ether gave a colourless solid (0.35 g)O A portion (0.32 g) of this solid was treated with a mixture of anisole (0.6 ml), trifluoroacetic acid (10 ml) and water(10 drops) at 22 for 15 minutes.
The mixture was concentrated to ca 3 ml then poured into benzene (100 ml). Ethyl acetate and tetrahydrofuran were added to give a solution. This solution was concentrated in vacuo to an oil which was stirred with ether ~- to give a powder (0.31 g).
A portion (0.1 g) of this powder was stirred with water (50 ~I) and trifluoro~cetic acid (1 ml~ for 10 ,, ~
.

,, ~
:, ~L3~2~ 37_ minutes. The mixture was waahed wlth ethyl acetate and ether and the aqueous phase was freeæe-dried to give the title compound ~0.09 g) associated with 1.2 moles of tri-fluoroacetic acid; [a]p~13.2 (c 0 49, DMSO), AmaX (pH6 phosphate) 248.5 nm (El/m2217 E16,050) with in1ections at 243 nm (El/m221, E16,0003 and 296 mn (ElCmg8, ~6,860).
Example 3 a) Diphenylmethyl (lS_5,6R~-7-formamido-3~(3_ methyl-~,2j3-triazolium-1-~h~= I-h-3-em-4-carboxylate, l-Oxide, l~romide Salt A solution of diphenylmethyl (lS,6R,7R)-3--bromomethyl-7-formamidoceph-3-em-4-carboxylate, 1-oxide (1 g) in N,N-dimethylformamide (3 ml) was stirred for 19 hours at 22 with l-methyl-192,3-triazole (1.10 g).
The reactlon mixture was added dropwise to ether to give the title compound (1.13 g) as a solid; v (Nujol) 3390 (NH), 1795 (,~-lactam), 1726 (C02R) and 1684 cm (CONH) and ~(~ISO-d6) 1.07 and 1.22 (2s triazol-4H
and 5H respectively), 1.77 (s, HCONH), 3.82 (dd~ J 9 and 5Hz, 7-H), 4.84 (d, J 5Hz, 6-H), 5.73 (s, ~-Me) and 5.90 and 6.19 (AB~ J 18Hz, 2-H2).
b) Diphenylmethyl (lS,6R,7R)-7~amino~3-(3-methyl-1~2,3-triazolium-1-yl)metk~lceph~3~em-4 carboxylate, l-Oxide Hydrochloride and Bromide Salts A stirred suspension o the product of stage a) (1.00 g3 in dry methanol was treated with phosphoryl chloride (0.48 ml) at 0 to 5 for 2 hours. The resulting solution was added dropwise to ether (100 ml) to give a gum which was stirred with ethyl acetate 30 (50 ml) for 13~ hours.

'~
' .. ~

_38 _~ ~ 3~

The resulting powder was washed with ether to give the title compound (0.700 g3 a~ a ~olid~ ~max (EtOH~ 278 nm (E~ cm 107~ vmax (Nujol) 3700 to 2290 (~H3~, 1805 (~ lact~m) and 1729 cm (C02R).
c) ~

2-oxyimino2~2-(2~trityl ~inothiazol~ vl)~ce~ ~lc;-Phosphorus pentachloride (~ ll g) in dry dichloromethane (lO ml) at 0 was treated with theproduct of Preparation 4 (0.295 g) and the solution was stirred for 30 minutes at 0. Triethylamine (0.16 ml) was added and stirring was continued for 10 minutes at 0. The resulting solution was added drop-wise over 5 minutes to a vigorously stirred suspension of the product o stage b) (0.303 g) in dichloromethane (15 ml) at 0. The mixture was stirred at 0 to 15 for 14 hours and the resulting solution was stored at -20 for 15 hours. The solution was poured into ethyl acetate (100 ml) and water (100 ml). The organic phase was separated and washed successively with water and brine, then dried and evaporated in vacuo to a foam (0.4 g). This foam was stirred with ether (30 ml~ for 30 minutes to give a solid which was washed with ether to give the title co~ound (0.35 g) as a solid, [a]22 -16 (c 1.0, DMSO) J ~inf (CHC13) 267 nm ( lcm 169).
The title compound may then be converted into (6Rj7R~-7~[(Z)-2-(2-aminothiazol-4~yl~-2-(2-carboxy-prop-2-oxyimino)acetamido]~3-(3-methyl-1,2,3~triazolium~

~ ~ 3~3 _ 39 _ l-yl)methylceph-3-em-4-carboxylate as described in Example l.
Example 4 a) Diphenylmethyl ~lS~6R~7R)-3-(1 7 2~3-triazolium-1~ methyl-7 [(Z)-2~ t-butoxycar'bonylcyclobut-1-oxyimino)-2-(2- tritylaminoth-iazol-4~yl)acetamido~ceph-3-em-4-carboxylate~ l-oxide A solution of the product of Example 2a) (l g) in N,N-dimethylformarnide (3 ml) was treated with 1,2,3-triazole (0.113 g). The reaction mixture was stirredat ca. 20 for 24 hours and then more triazole (0.113 g) was added and the mixture was stirred for ca. 2 hours at ca 20 and then refrigerated for ca. 60 hours. The mixture was diluted with ethyl acetate (150 ml) and lS the organic solution was washed with 2N-hydrochloric acid (2 x 50 ml) and brine (50 ml) t'h~n dried over magnesium sulphate and evaporated in vacuo to a foam (0.88 g). Chromatography of this foam on preparative thin-layer plates using toluene:ethyl acetate:acetic acid =
20:40:1 as eluant gave the title compound ~O l g) as a solid with ~inf (EtOH) 260 nm (ElCm 199) and 300.5 nm (ElCm 61) and ~ (DMSO-d6), 2.03 and 2.26 (2s, triazolium protons~, 3.19 (s, thiazol 5-H)~ 3.8 to 4.1 (m, 7-H), 4.92 (d, J 5Hz, 6-H), 7.4 to 7.8 (m, cyclobut-2 and 4-yl protons), 7.8 to 8.2 (m, cyclobut-3-yl protons) and 8.62 (s, t butyl).
b) Diphenylmethyl (15~6R,7R~-3-(3-methyl-1,2,3-triazolium-l-yl)methyl-7-~(Z)-2-(1 t-butoxycarbonyl-cyclobut-l--oxyimino~~2-(2~tritylaminothiazol-4-yl)-acetamido]c_ph-3-em-4-carboxylate, _oxide, Iodide Salt A solution of the Product from stage a) (0.08 g) - 40 ~

in iodomethane ~ 2 ml) was stirred at 22 for 66 hours.
Excess iodomethane was evaporated in vacuo to give a solid. This product was triturated with ether and the solid collected by filtration and dried in vacuo over phosphorus pentoxide to give the title compound (0.067 g) as a solid; ~a~D -16~2 (c O.5, DMSO), ~i f (EtOH) 260 nm (ElCm 160) and 305 nm (ElCm 58).

Ex m~le 5 a) t~Butyl (6R,7R)-3-Acetoxymethyl-7-~(Z)-2-(2-t-butoxy-carbonylprop-2-oxyimino)-2-(2-tritYlaminothia~oL-4~yl) acetamido~ ce~h-3-em-4-carboxylate A stirred solution of the product of Preparation 4 (572 mg) and t-butyl ~6R,7R)-3-acetoxymethyl-7-aminoceph-3-em-4~carboxylate (328 mg~ in dimethylfonnamicle (10 ml) was cooled to 0, and l-hydroxybenzotriazole (150 mg) was added, followed by dicyclohexylcarbodiimide (225 mg). The mixture was warmed to room temperature, stirred for 5 hours, and allowed to stand overnight. The mixture was filtered, and the white solid washed with a little ether.
The filtrate and washings were diluted with water ~50 ml) and extracted with ethyl acetate. The organic extracts were combined, washed successively with water, 2N
hydrochloric acid, water, sodium bicarbonate soLution, and saturated brine, dried and evaporated. The residue was elu-ted through a silica column with ether. The product-containing eluate was collected and concentrated to give the title compound (533 mg). A portion was recrystallised from di-isopropyl ether, m.p. 103 to 113 (decomp.3;
[a~D + 8.5 (c, 1.0, DMSO).

3~

4-yl?_2-(2-carboxyE~roe~2-oxyimino)-acetami ~ ce~h 3-em-The product of Stage a) ~200 g) was dissolved in formic acid (800 ml) pre-cooled to ~10 and concentrated hydrochloric acid (60 ml) was added over 5 minutes to the stirred mixture. Stirring was continued at 20 to 22 for 14 hours before cooling to +10 and filtering. The bed was washed with formic acid (30 ml).
The combined filtrate and wash were concentrated by evaporation at 20 to a yellow foam which was triturated with ethyl acetate (800 ml). The solid which deposited was collected by filtration, washed with ethyl acetate (200 ml) and dried in vacuo at room temperature overnight to glve the title compound (124.6 g) AmaX
(ethanol) 234.5 nm (ElCm 311)-_ (6R,7R~7-[(Z)-2-(2-A inothiazol-4-yl)-2-(2-carboxyprop-2-oxyimino)acetamido~-3-(3-methy1-1,2,3-triazolium-l~yl)methyl-ceph-3-em-4-carboxylate~sodium Salt (6R77R)-3-Acetoxymethyl-7-[(Z)-2-(2-aminothiazol-4-yl)-2-(2-carboxyprop-2-oxyimino)acetamido~-ceph-3-em-4-carboxylic acid, hydroch]oride salt (0.564 g), sodium hydrogen carbonate (0.27 g !,sodium iodide (1.8 g ), water (0~30 ml) and 1-methyl-1,2,3-triazole (0.25 ml) were heated to 80 for 14 hours and the solu-tion was left to cool. The resulting solid was triturated with acetone (10 ml) and the product was filtered off, washed with acetone a~d ether and dried rapidly in-vacuo to give a ' .

' :
, - \
~ 3~2~

solid (0.66 g). This product was purified on a column of Amberlite XAD-2 resin (100 g) which was eluted successively with water then water:ethanol (4:1).
Appropriate fractions were combinPd, evaporated to ca. 150 ml then freeze-dried to give the title compound (0.203 g) as a foam with ~ma~(pH6 buffer) ` 238 nm (ElCm295) with in~lections at 256 nm (ElC%m270) and 295 nm (E lCml4i3 and ~(D20) 1.39 and 1.49 (2 broad s, triazole protons), 3.00 (broad s, thiazol 5-H), ; 10 5.69 (s, ~CH3), 6.29 and 6.62 (ABq, J ca. 18 Hz, 2-H2) and 8.52 (s, CMe~).

.'; ' ~
.

~ ' -~3~Z~

The antibiotic compounds of the invention may be formulated for administration in any convenient way, by analogy with other antibiotics and the invention therefore includes within its scope pharmaceutical compositions comprising an antibiotic compound in accordance with the invention adapted to use in human or veterinary medicineO
Such compositions may be presented for use in conventional manner with the aid of any necessary pharmaceutical carriers or excipients.
The antibiotic compounds according to the invention may be formulated for injection and may be presented in ~nit dose form in ampoules, or in multi-dose containers, if necessary with an added preservative. ~le compositions may also take such forms as suspensions, solutions, or i5 emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilising and/or dispersing agents. Alternatively the active ingredient may be in powder form for reconstitution with a suitable vehicle, e.g. sterile, pyrogen-free water, before use.
If desired, such powder formulations may contain an appropriate non-toxic base in order to improve the water-solubility of the active ingredient and/or to ensure that when the powder is reconstituted with water, .
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the pH of the resulting ~queous formulation ls physio-logically acceptable. Alte~natively, the base may be present in the water with which the powder is reconstit-uted. The base may be, for example, an inorganic base such as sodium carbonate, sodium bicarbonate or sodium acetate, or an organic base such as lysine or lysine acetate.
The antibiotic compounds may also be formulated as suppositories, e.g. containing conventional suppository bases such as cocoa butter or other glycerides.
For medication of the eyes or ears, the prepara-tions may be formulated as individual capsules~ an liquid or semi-solid form, or may be used as drops.
Compositions for veterinary medicine may, for example, be formulated ~s intramammary preparations in either long acting or quick-release bases.
The composltions may contain from 0.1% upwards, e.g. 0.1-99%, of the active material, depending on the method of administration. When the compositions comprise dosage units, each unit should preferably contain 50-lS00 mg of the active ingredient. The dosage as employed for adult human treatment will preferably range rom 500 to 6000 mg per day, depending on the route and frequency of administration. For example, in adult human treatment ; 25 1000 to 3000 mg per day administered intravenously or intramuscularly will normally suffice. In treating Pseudomonas infections higher daily doses may be required.
The antibiotic compounds according to the invention may be administered in combination with other therapeutic agents such as antibiotics, for example penicillins or ~ other cephalosporins.

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The following formulation illustrates how a compound according to the invention may be made up into a pharmaceutical composition Formulation - For Injection ....
5 Formula ~er vial (6R,7R)-7-~(Z)-2-(2-Aminothiazol 4-yl~-2-(1-carboxycyclobut-l-yloxyimino)acetamido]-3-(3-methyl-1,2,3-triazolium-1 yl)methylceph-- 3-em-4-carboxylate 500 mg 10 sodium carbonate, anhydrous 47 mg Method Blend the sterile cephalosporin antibiotic with sterile sodium carbonate under aseptic conditions. Fill aseptically into glass vials under a blanket of sterile nitrogen. Close the vials using rubber dlscs, or plugs, heLd in position by alumlnium overseals, thereby preventing gaseous exchange or ingress of microorganisms.
Reconstitute the product by dissolving in Water for Injections or other suitable sterile vehicle shortly be before administration.
(6R,7R)-7-[(Z)-2-(aminothiazol-4-yl)-2-(2-carboxyprop-2-oxyimino)-acetamido~-3-(3-methyl-1,2,3~triazolium-1-yl) methyl-ceph-3-em~4-carboxylate may be formulated in a similar manner.

Claims (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the preparation of cephalosporin anti-biotics of general formula (I) (wherein Ra and Rb, which may be the same or different, each represent a C1-4 alkyl group or Ra and Rb together with the carbon atom to which they are attached form a C3-7 cycloalkyli-dene group; and R1 represents a C1-4 alkyl group) and non-toxic salts and non-toxic metabolically labile esters thereof, which comprises (A) acylating a compound of formula (II) (wherein R1 is as defined above; B is >S or >S?O and the dotted line bridging the 2-, 3- and 4-positions indicates that the compound is a ceph-2-em or ceph-3-em compound), or a salt or N-silyl derivative thereof or a corresponding compound having a group of formula -COOR2 at the 4-position (where R2 is a hydrogen atom or a carboxyl blocking group) and having an associated anion A?, with an acid of formula (III) (wherein Ra and Rb are as defined above; R3 represents a carboxyl blocking group; and R4 is an amino or protected amino group) or with an acylating agent corresponding thereto; (B) react:ing a compound of formula (IV) (wherein Ra, Rb, R4, B and the dotted line are as hereinbefore defined; RS and R5a may independenkly represent hydrogen or a carboxyl blocking group; and X is a leaving group) or a salt thereof with an alkyltriazole of the formula (V) (wherein R1 is as defined above); or (C) alkylating a compound of formula (VI) (wherein Ra, Rb, R4, B and the dotted line are as hereinbefore defined; and R5 and R5a both represent carboxyl blocking groups) to introduce the R1 substituent into the triazole ring in formula (VI); whereafter if necessary and/or desired in each instance, any of the following reactions, in any appropriate sequence, are carried out:-i) conversion of a .DELTA.2-isomer into -the desired .DELTA.3-isomer, ii) reduction of a compound wherein B is >S?O to form a compound wherein B is >S, iii) conversion of a carboxyl group into a non-toxic salt or non-toxic metabolically labile ester function, and iv) removal of any carboxyl blocking and/or N-protecting groups.

2. A process as claimed in claim 1 for the preparation of compounds of formula (I) wherein at least one of Ra and Rb represents a methyl or ethyl group.

3. A process as claimed in claim 1 for the preparation of compounds of formula (I) wherein Ra and Rb together with the carbon atom to which they are attached form a C3-5 cycloalkylidene group.

4. A process as claimed in claim 1 for the preparation of compounds of formula (I) wherein R1 represents a methyl group.

5. A process as claimed in claim 1 wherein in the starting materials Ra, Rb and Rl all represent methyl groups.

6. A process for the preparation of (6R,7R)-7-[(Z)-2-(2-aminothiazol-4-yl)-2-(2-carboxyprop-2-oxyimino)-acetamido]-3-(3-methyl-1,2,3-triazolium-1-yl)methyl-ceph-3-em-4-carboxylate, which comprises reacting diphenylmethyl (lS, 6R, 7R)-3-bromomethyl-7-[(Z)-2-(2-t-butoxycarbonylprop-2-oxyimino)-2-(2-tritylaminothiazol-4-yl)acetamido]ceph-3-em-4-carboxylate, 1-oxide with l-methyl-1,2,3-triazole, reducing the 1-oxide function of the resulting product, and then splitting off the blocking or N-protecting diphenylmethyl, t-butoxycarbonyl and trityl groups.

7. A process as claimed in claim 1 wherein in the starting materials Ra and Rb together with the carbon atom to which they are attached form a cyclobutylidene group, and R1 is a methyl group.

8. A process for the preparation of (6R,7R)-7-[(Z)-2-(2-aminothiazol-4-yl)-2-(1 carboxycyclobut-1-oxyimino)-acetamido]-3-(3-methyl-1,2,3-triazolium-1-yl)methyl-ceph-3-em-4-carboxylate, which comprises reacting diphenylmethyl (lS,6R,7R)-3-bromomethyl-7-[(Z3-2-(1-t-butoxycarbonylcyclobut-1-oxyimino)-2-l2-tritylaminothiazol-4-yl)acetamido]ceph-3-em-4-carboxylate, l-oxide with l-methyl-1,2,3-triazole, reducing the l-oxide function of the resulting product, and then splitting off the blocking or N-protecting diphenylmethyl, t-butoxycarbonyl and trityl groups.

9. A process for the preparation of (6R,7R) 7-[(Z)-2-(2 aminothiazol-4-y1)-2-(2-carboxyprop-2-oxyimino)-acetamido]-3-(3-methyl-1,2,3-triazolium-1-yl)methyl-ceph-3-em-4-carboxylate, which comprises acylating diphenylmethyl (lS,6R,7R)-7-amino-3-(3-methyl-1,2,3-triazolium-1-yl)methylceph-3-em-4-carboxylate, l-oxide hydrochloride and bromide salts with(z)-2-(2-t-butoxycarbonylprop-2-oxyimino)-2-(2-tritylaminothiazol-4-yl)acetyl chloride reducing the l-oxide function of the resulting product, and then splitting off the blocking or N-protecting diphenylmethyl, t-butoxyearbonyl and trityl groups.

10. A cephalosporin antibiotic of formula (I) as defined in claim 1 or a non-toxic salt or non-toxic metabolically labile ester thereof, when prepared by the process of claim 1 or by an obvious chemical equivalent thereof.