GB1602725A - 7-(a-oxyiminoacetamido)-ceph-3-em-4-carboxylic acid derivatives - Google Patents

Description

(54) 7ss-(α-OXYIMINOACETAMIDO)CEPH-3-EM-4-CARBOXYLIC ACID DERIVATIVES (71) We, GLAXO OPERATIONS UK LIMITED. a British Company of Greenford, Middlesex. do herebv declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed. to be particularly described in and by S the following statement: This invention is concerned with improvements in or modifications of the invention described in our Specification No. 1496757 in which we have described and claimed 7ss-acylamidoceph-3-em-4-carhoxylic acids and non-toxic derivatives thereof which are characterised in that the said acylamido moiety has the formula

[wherein R is a thienvl or furvl group. R and Rb, which may be the same or different, are each selected from hydrogen. C1-4 alkyl. C24 alkenyl. CR7 cycloalkyl, phenyl. naphthyl.

thienyl. furvl. carboxy, C2-5 alkoxy-carbonyl and cyano. or R and Rb together with the carbon atom to which they are attached form a C3-7 cycloalkylidene or cvcloalkenvlidene group: and nl and n are each ()or 1 such that the sum of m and n is 0 or 1 l. the compounds being syn isomers or existing as mixtures of svn and anti isomers containing at least 9()Yc of the syn isomer. (The compounds are named with reference to "cepham" after J. Amer.

Chew. Soc 1C)67. 8J. 34()(). the term "cephem" referring to the basic cepham structure with one double bond: the syn and anti configurations are assigned on the basis of the work of Ahmad and Spencer as reported in Can. J. Chem. 1961. 39. 134()).

The present invention is concerned with compounds falling within the scope of the aforesaid specification but which are not specifically disclosed therein. Thus, the present invention provides antibiotic compounds of the general formula

or, where the group Y carries a positive charge, compounds of the general formula (I) having the group -COOe at the 4- position.

[wherein Y is selected from:a) a group of formula

(wherein Rl is hydrogen. or a carbamoyl, carboxy. carboxymethyl, sulpho or methyl group); b) a group of formula - SR' (wherein Rl represents a 5- or 6- membered heterocyclic group having one or more heteroatoms selected from O,N and S. which may be unsubstituted or substituted by. for example one or more lower alkyl (e.g. methyl) or phenyl groups. for example, a thiadiazolyl. e.g. 5-methyl-l, 3.4-thiadiazol-2-yl; diazolyl; triazolyl; tetrazolyl e.g. 1-methyl - tetrazol-5-yl: thiazolyl; thiatriazolyl; oxazolyl; oxadiazolyl; pyridyl; or pyrimidyl group; c) a group of formula - O. CO. R2 (wherein R2 is C, 7 alkyl). and d) a group of formula - O. CO. AR3 (wherein R3 is hydrogen or C,7 alkyl and A is > O. > S or > NH, provided that when A is > O or > S. R' is not hydrogenl and non-toxic derivatives thereof, the said compounds being svn isomers or existing as mixtures of syn and anti isomers containing at least 75cos of the syn Isomer.

These compounds are advantageously syn isomers or exist as mixtures of svn and anti isomers containing at least 90c4 of the syn isomer. We prefer the compounds to be syn isomers essentially free from the corresponding anti isomer.

These compounds of formula I exhibit broad spectrum antibiotic activity characterised by particularly high activity against gram negative microorganisms. including those which produce B-lactamases. and also possess very high stability to ss-lactamases produced by a range of gram negative organisms.

By "non-toxic derivatives" is meant those derivatives which are physiologically acceptable in the dosage at which they are administered. Such derivatives may include, for example. salts. biologically acceptable esters, I-oxides and solvates (especially hydrates).

Non-toxic salt derivatives which may be formed from the compounds of general formula I include inorganic base salts such as alkali metal salts (e.g. sodium and potassium salts) and alkaline earth metal salts (e.g. calcium salts); amino acid salts (e.g. lysine, and arginine); organic base salts (e.g. procaine. phenylethylbenzylamine, dibenzylethylenediamine, ethanolamine, diethanolamine, triethanolamine and N- methylglucosamine salts). The salts may also be in the form of resinates formed with, for example, a polystyrene resin or cross-linked polystyrene divinylbenzene copolymer resin containing amino or quaternary amino groups. Where appropriate, acid addition salts, e.g. with hydrochloric, hydrobromic, sulphuric, nitric, phosphoric, trifluoroacetic, toluene-p-sulphonic and methane sulphonic acids may also be formed. Use of highly soluble base salts (e.g. alkali metal salts such as the sodium salt) of compounds of formula I is generally advantageous in therapeutic applications because of the rapid distribution of such salts in the body upon administration.

Where, however, insoluble salts of compounds (I) are desired in a particular application, e.g. for use in depot preparations, such salts may be formed in conventional manner, for example with appropriate organic amines.

Biologically acceptable, ester derivatives which may be formed from compounds of formula I include metabolically labile esters. Where the carboxylate ester is metabolically labile, the parent acid will be generated in vivo. Examples of such esters include acyloxyalkyl esters. e.g. C,.6 alkanoyloxymethyl esters such as acetoxymethyl or pivaloyloxymethyl esters.

The compounds of formula (I) above where Y represents a carbamoyloxy, acetoxy, 1-pyridinium, 5-methyl-1.3 ,4-thiadiazol-2-yl-thio . or 1-methyltétrazol-5-yl-thio group are particularly preferred on account of their especially good broad spectrum antibiotic activity.

A characteristic feature of these compounds is their high in vitro activity against gram-negative organisms such as Enterobacter cloacae, Serratia marcescens and Klebsiella aerogenes. Such compounds have particularly high activity against strains of Escherichia coli, Haemophilus irzfluenzae and Proteus organisms, e.g. strains of Proteus organic and Proteus rnirabilis. The compounds also show unusually high activity against Pseudomonas organisms, for example strains of Pseudomonas aeruginosa.

The compounds of formula (I) may be used for treating a variety of diseases caused by pathogenic bacteria in human beings and animals. such as respiratory tract and urinary tract infections.

The compounds according to the invention may be prepared by any convenient method, for example by techniques analogous to those described in British Patent Specification No.

1399sus6.

Thus according to one 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 derivative thereof which comprises either (A) condensing a compound of the formula

[wherein B is > S or > S+O (a- or -): R4 represents hydrogen or a carboxyl blocking group, e.g. the residue of an ester-forming aliphatic or araliphatic alcohol or an ester-forming phenol. silanol or stannanol (the said alcohol. phenol, silanol or stannanol preferably containing l-9ü carbon atoms) or a symmetrical or mixed anhydride group derived from an appropriate acid; the dotted line bridging the 2-, 3- and 4- positions indicates that the compound is a ceph-2-em or ceph-3-em compound; and Y is as hereinbefore defined] or a salt. e.g. an acid addition salt such as a hydrochloride, hydrobromide. sulphate. nitrate. phosphate. methane sulphonate or tosylate, or an N-silylated derivative thereof, with an acid of formula

(wherein R5 is a carboxyl blocking group, e.g. a group as hereinbefore defined in connection with R4) or with an acylating agent corresponding thereto: or (B), reacting a compound of the formula

(wherein R and the dotted line are as hereinbefore defined; each R4 may independently represent hydrogen or a carboxyl blocking group; and Y' is a replaceable residue of a nucleophile, e.g. an acetoxy. dichloroacetoxy or hydroxy group or a halogen atom such as chlorine. bromine or iodine) with a nucleophile serving to introduce the group Y; whereafter, if necessary and/or desired in each instance, any of the following reactions (C) in any appropriate sequence, are carried out:i) conversion of a 2 isomer into the desired 3 isomer, ii) reduction of a compound wherein B is > S yO to form a compound wherein B is > S.

iii) deacylation of a 3-acyloxymethyl compound to form a 3-hydroxymethyl compound, iv) acylation of a 3-hydroxymethyl compound to form a 3-acyloxymethyl compound.

v) carbamovlation of a 3-hydroxymethyl compound to form an unsubstituted or substituted 3-carbamoyloxymethyl compound, vi) removal of carboxyl blocking groups; and vii) esterification of the 4-carboxyl group with a biologically acceptable ester group; and finally (D) recovering the desired compound of formula I or a non-toxic derivative thereof, if necessary after separation of isomers.

Non-toxic derivatives of the compounds of formula I may be formed in any convenient way. for example according to methods well known in the art. Thus, for example, base salts may be formed by reaction of the cephalosporin acid with sodium 2-ethylhexanoate or potassium 2-ethylhexanoate. Biologically acceptable ester derivatives may be formed using conventional esterifying agents. I-Oxides may be formed by treatment of the corresponding cephalosporin sulphide with an appropriate oxidising agent, for example with a peracid such as metaperiodic acid. peracetic acid. monoperphthalic acid or m-chloroperbenzoic acid. or with t-butyl hypochlorite, this last reagent conveniently being employed in the presence of a weak base such as pyridine.

Acvlating agents which may be employed in the preparation of compounds of formula I include acid halides, particularly acid chlorides or bromides. Such acylating agents may be prepared by reacting an acid (III) or a salt thereof with a halogenating agent e.g.

phosphorus pentachloride, thionyl chloride or oxalyl chloride. Treatment of the sodium, potassium or triethylammonium salt of the acid (III) with oxalyl chloride is advantageous in that under these conditions isomerisation is minimal.

Acylations employing acid halides may be effected in aqueous and non-aqueous reaction media. conveniently at temperatures of from -50 to +50"C, preferably -20 to +3() C. if desired in the presence of an acid binding agent. Suitable reaction media include aqueous ketones 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), inorganic bases (e.g. calcium carbonate or sodium bicarbonate), and oxiranes such as lower 1 .2-alkylene oxides (e.g. ethvlene oxide or propylene oxide) which bind hydrogen halide liberated in the acylation 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 desirably conducted in the presence of a condensation agent, for example a carbodiimide such as N.N'-diethvl-.

dipropyl- or diisopropylcarbodiimide. N,N'-dicyclohexylcarbodiimide or N-ethyl-N '-y- dimethylaminopropylcarbodiimide; a carbonyl compound such as carbonyldiimidazole; or an isoxazolinium salt such as N-ethyl-5-phenylisoxazolinium perchlorate. Acylation reactions of this type are desirably effected in an anhydrous reaction medium, e.g.

methylene chloride, dimethylformamide or acetonitrile.

Acylation may also be effected with other amide-forming derivatives of acids of formula (III) such as, for example, a symmetrical anhydride or a mixed anhydride (e.g. with pivalic acid or formed with a haloformate such as a lower alkylhaloformate) or activated esters.

Any transformations of substituents at the 3-position which may be necessary in the preparation of particular compounds of formula I may, for example, be effected by methods described in the literature. Compounds of formula I may thus be prepared for example by the reaction of a 3-acetoxymethyl cephalosporin compound with a pyridine nucleophile as described in British Patent Specification No. 912,541; a sulphur-linking nucleophile as described in British Patent Specification No. 1,012,943: a sulphur-linking nucleophile as described in British Patent Specifications Nos. 1,059,562; 1,101,423 and 1,206.305; or a nitrogen-linking nucleophile as described in British Patent Specifications Nos. 1,030,630; 1.082,943 and 1,082.962.

Compounds of formula IV possessing a 3-substituent -CH2Y wherein Y'is a hydroxy group may be prepared by the methods described in British Patent Specifications Nos. 1,121.308; 1,399,086 and 1,474,519. 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.

Carbamoylation of 3-hydroxymethyl compounds may be effected by conventional methods. Thus. for example. a 3-hydroxymethyl cephalosporin may be reacted with an isocvanate of formula R' .NCO (wherein RC represents a labile substituent group or an alkyl group) to give a compound containing a 3-position substituent having the formula -CH,O.CONHR' (wherein Re has the above defined meaning). Where RC is a labile substituent this substituent may if desired subsequently be cleaved, e.g. by hydrolysis, to form a 3-carbamoyloxymethyl group. Labile groups RC which are readily cleavable upon subsequent treatment include chlorosulphonyl and bromosulphonyl; halogenated lower alkanoyl groups such as dichloroacetyl and trichloroacetyl; and halogenated lower alkoxycarbonyl groups such as 2,2,2-trichloroethoxycarbonyl. These labile Re groups may generally be cleaved by acid or base catalysed hydrolysis (e.g. by base catalysed hydrolysis using sodium bicarbonate). Cephalosporin compounds of formula I in which Y is a group of formula - O.CO.R (wherein R- as defined above) may, for example, be prepared from a cephalosporin compound of formula (IV) having a -CH.Y' group (where Y' = OH or the residue of an acid H X which has a pKa of not more than 4.0, preferably not more than 3.5, as measured in water at 250C) at the 3-position. Y' may thus, for example represent chlorine. bromine. iodine. formyloxy. an acetoxy group having at least one electronwithdrawing substituent on the a-carbon atom. or a nuclear substituted benzoyloxy group (the nuclear substituent being of the electron withdrawing type as described in British Patent Specification No. 1.241657), and the nucleophilic displacement reaction to form the desired 3-position acyloxymethyl may be carried out as described in our aforesaid British Patent Specification No. 1.941,657. Alternatively, where Y' is hydroxy, a compound of formula I wherein Y is a group of formula -O.CO.R2 (wherein R2 is as defined above) may be obtained by acylation analogous with that described in British Patent Specification No.

1,141,293, i.e. by aralkylating the 4-carboxy group, acylating the 3-hydroxy-methyl group of the protected compound and subsequently removing the aralkyl group.

Where a compound of formula I is obtained as a mixture of isomers, the syn isomer may be obtained by. for example. conventional methods such as crystallisation or chromatography. Syn and anti isomers may be distinguished by appropriate techniques, e.g.

by thin layer chromatography or by their proton magnetic resonance spectra.

The carboxylic acids of formula (IIi) may be prepared for example in a manner illustrated in the preparations given hereinafter. Such acids may be converted to the corresponding acid halides and anhvdrides by conventional methods.

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 form of mixtures of the svn isomers and the corresponding anti isomers containing at least 90% of the syn isomer are preferably used.

Carboxyl blocking groups R4 and R5 used in the preparation of compounds of formula I or in the preparation of necessary starting materials are desirably groups which may readily be split off at a suitable stage in the reaction sequence, conveniently as the last stage. It may, however, be convenient in some instances, especially for the group R4, to employ biologically acceptable metabolically labile carboxyl blocking groups such as acyloxymethyl groups (e.g. acetoxymethyl, acetoxyethyl and pivaloyloxymethyl) and retain these in the final product to give a biologically acceptable ester derivative of a compound of formula I.

Suitable carboxyl blocking groups are well known in the art, a list of representative blocked carboxyl groups being included in British Patent Specification No. 1,399,086.

Preferred blocked carboxyl groups include aryl C,.6 alkoxycarbonyl groups such as p-methoxybenzyloxycarbonyl, p-nitrobenzyloxycarbonyl and diphenylmethoxycarbonyl; Ci.b alkoxycarbonyl groups such as t butoxycarbonyl; and C1.6 haloalkoxycarbonyl groups such as 2,2,2-trichloroethoxycarbonyl. The carboxyl blocking group or groups may subsequently be removed by any of the appropriate methods disclosed in the literature; thus. for example, acid or base catalysed hydrolysis is applicable in many cases. as are enzymically-catalysed hydrolyses.

The antibiotic compounds of the invention, e.g. compounds of formula I and non-toxic derivatives thereof, 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 for use in human or veterinary medicine. 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 unit dose form in ampoules, or in multi-dose containers with an added preservative. The compositions may take such forms as suspensions, solutions, or 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.

The antibiotic compounds may also be presented in a form suitable for absorption by the gastro-intestinal tract, e.g. as tablets or capsules. The antibiotic compounds may also be formulated as suppositories e.g. containing conventional suppository bases such as cocoa butter or other glycerine.

Compositions for veterinary medicine may. for example, be formulated as intramammary preparations in either long acting or quick-release bases.

The compositions may contain from O.1C/c upwards, e.g. 0.1-99C/c, preferably from 10-60C/e of the active material. depending on the method of administration. When the compositions comprise dosage units, each unit will preferably contain 50 - 1500 mg of the active ingredient. The dosage as employed for adult human treatment will preferably range from 50() to 5000 mg per day, depending on the route and frequency of administration, although in treating Psezidoin on as 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.

The following examples illustrate the present invention; all temperatures are in "C.

PREPARATION 1 t-Butvl 7-lo co7lo-3-fo) )7lV1OXVp) opioslate A solution of t-butyl acrylate (12.8 g.) in chloroform (50 ml.) and formic acid (11.3 ml.) was stirred in an ice-bath during the dropwise addition over 2 hr. of a solution of N,N-dibromobenzenesulphonamide (15.75 g.) in a mixture of chloroform (50 ml.) and formic acid (5.7 ml.). The mixture was stirred for a further 16 hr. at room temperature and then filtered. The filtrate was washed successively with water, pH 8 buffer (three times) and brine. The solution was dried, evaporated to an oil and distilled to give the title compound (20.47 g) b.p. 69-71V1.0 mm; T(CDC1R:6() MHz) 1.93 (s, formyl), and 8.48 (t-butyl protons).

PREPARATION 2 N-(l-t-Butvloxvearbonvl-2-formyloxyethoxv)phthalimide t-Butyl 2-bromo-3-formyloxypropionate (50.6 g.) was added to a solution of Nhydroxyphthalimide (32.6 g.) and triethylamine (60 ml.) in dry dimethylformamide (120 ml.) and the mixture was stirred for 18 hr. at room temperature. The mixture was poured into ice water (11.) and extracted with ethyl acetate (3 x 200 ml.). The combined organic extracts were washed with sodium bicarbonate solution, until the washings were colourless, then with water and brine. The ethyl acetate solution was dried and evaporated under reduced pressure to an oily solid (53.2 g.) that was crystallised from ethanol to give the title compound (20.85 g.) m.p. 64.5-67.5 ;T (DMSO-d 6: 60 MHz) 1.67 (s, formyl), 2.11 (s, phthalimide protons), 4.99 (t. J 4 he: O-CHCO2tBu), 5.46 (d, J 4 Hz: -CH2) and 8.54 (s, t-butyl).

PREPARATION 3 N(l-t-Butyloxycarbonyl-2-hydroxyethyloxy)phthalimide A solution of phosphorus oxychloride (2.46 ml.) in chloroform (35 ml.) was added to a stirred ice-cooled solution of N( 1-t-butyloxycarbonyl-2-formyloxyethoxy)-phthalimide (10.3 g.) in a mixture of chloroform (185 ml.) and methanol (235 ml.). The mixture was stirred for a further 1/2 hr. at room temperature and then treated with solid sodium bicarbonate (ca. 10 g.) before being evaporated to dryness. The residue was distributed between ether and water and the aqueous phase was extracted with more ether. The combined extracts were washed successively with sodium bicarbonate solution (twice), water and brine. Evaporation of the dried ether extracts gave a yellow gummy solid (7.01 g.) that was crystallised from ether to give the title compound (2.81 g.) m.p. 86.8 ; # (CDCl,:60 MHz) 2.14 (broad s. phthalimide protons), 5.42 (m, O-CH-), 6.01 (m. CH2) and 8.44 (t-butyl protons).

PREPARATION 4 N-(1-t-Butyloxycarbonyl-2-mesyloxyethoxy)ph phthalimide Methanesulphonyl chloride (1.35 ml.) was added to a solution of N-(l-tbutyloxycarbonyl-2-hydroxyethoxy)-phthalimide (2.65 g.) in pyridine (25 ml.) and the mixture was stirred for 18 hr. at room temperature. The solvent was removed under reduced pressure and the residue was dissolved in ethyl acetate and washed successively with water, dilute hydrochloric acid. sodium bicarbonate solution and water. Evaporation of the dried ethyl acetate solution gave a residue that was crystallised from ethanol to give the title compound (0.47 g.) m.p. 108.0-109.2 : t (DMSO-d6:6() MHz) 2.08 (s. phthalimide protons). 4.88 (m. O-CH CO2tBu) 5.34 (m, -CH2-), 6.70 (s, CH3) and 8.51 (s, t-butyl).

PREPARATION 5 N- (1 -t-Burvloxvcarbol2 vll isl vl) oxyphllzallmide A mixture of N-(l-t-butyloxycarbonyl-2-mesyloxyethoxy)-phthalimide (1.44 g.) and triethvlamine (().6() ml.) dissolved in ethyl acetate (20 ml.) was stirred for 24 hr. at room temperature. The mixture was washed successively with water, dilute hydrochloric acid and water. Evaporation of the dried ethyl acetate solution gave a solid (0.967 g.) that was crystallised from ethanol to give the title compound (0.491 g.) m.p. 115.4-116.2 ; T (DMSO-d6:60 MHz) 2.09 (s. phthalimide protons), 4.54 (q, J 4 Hz: =CH2) and 8.46 (s.

t-butyl).

PREPARATION 6 t-Butyi 3-Phthalimido-oxy-#'-pyrazoline-3-carboxylate A stirred solution of N'-(1-t-butyloxycarbonylvinyl)oxy phthalimide (8.0 g.) in ether (400 ml) was treated portionwise at Oo with ethereal diazomethane [from N-methvl-Nnitrosourea (12.0 g.)] until there was a permanent yellow colour. The mixture was stirred at room temperature overnight, then treated with additional ethereal diazomethane and stirred for a further 2 days. During this time some solvent was lost by evaporation and a white solid separated and was collected and washed with ether to give the pyrazoline (5.697 g). m.p. 123.1 : tm.lY (EtOH) 236.5 infl (E 10.900) and 294 nm (E 1,900).

PREPARATION 7 t-Butyl I-Phthalimido-oxycydopropanecarboxylate A solution of t-butyl 3-phthalimido-oxy-#-pyrazoline-3-carboxylate (17.0 g) in toluene (510 ml) was heated under reflux for 5 h, after which the solvent was evaporated off under reduced pressure. The residue in ethyl acetate was washed successively with 2Nhydrochloric acid, saturated aqueous sodium hydrogen carbonate, and water, dried and evaporated. The residual yellow solid (16.02 g) was chromatographed on Merck (registered trade mark) silica gel (400 g) eluting with ether, to give a gum which was crystallised from ether/petroleum ether to give the title compound (8.73 g), m.p. 78.6 ; Xm.ix (EtOH) 236.5 infl (E 10.600) and 293 mn (E 1,900).

PREPARATION 8 t-Butvl l-Amino-oxlcyclopropanecarboxylate t-Butyl 1-phthalimido-oxycyclopropanecarboxylate (3.4 g) in dry dichloromethane (55 ml) was stirred for 1 h. at room temperature with hydrazine hydrate (1.17 ml). The precipitate was filtered off and washed with dichloromethane, and the filtrate was washed successively with 5N-ammonium hydroxide, water, and brine, dried and evaporated to give the oxyamine as a yellow oil (1.832 g), t (CDCl3), 4.2 (2H, br s, NH2), 8.50 (9H, s, C(CH3)3), 8.75 (4H, m, -CH2CH2-).

PREPARATION 9 (1-t-Butyloxycarbonylcyclopropyl)oxyiminofur-2-ylacetic acid t-Butyl 1-amino-oxycvclopropanecarboxylat

EXAMPLE 2 a) (6R, 7R) -3-Acetoxymethyl-7-[(Z) - (I-carboxycyclopropyloxyimino) fur-2-ylacetamido]ceph-3-em-4-carboxylic acid Oxalyl chloride (1.05 ml) was added to a solution of (1-tbutyloxycarbonylcyclopropyl)oxyiminofur-2-ylacetic acid (2.95 g) in dichloromethane (70 ml) containing N,N-dimethylformamide (10 drops) and triethylamine (1.4 ml), stirred at 00.

The mixture was stirred for 1 hour without further cooling, then evaporated to dryness. The residue was treated with acetone (60 ml), and the mixture was filtered into a solution of (6R,7R)-3-acetoxymethyl-7-aminoceph-3-em-4-carboxylic acid (2.72 g) and sodium hydrogen carbonate (2.1 g) in water (70 ml) and acetone (15 ml). The mixture was stirred at room temperature overnight, after which the acetone was removed under reduced pressure.

The residue was diluted with water and extracted with ethyl acetate. The extracts were back-extracted with 59 aqueous sodium hydrogen carbonate and discarded. The combined aqueous solutions were acidified with 2N-hydrochloric acid while being stirred under ethyl acetate. The aqueous phase was extracted with ethyl acetate and the combined organic solutions were washed with water, dried and evaporated to give (6R, 7R)-3-acetoxymethyl7-[(Z)-(1-t-butyloxycarbonylcyclopropyloxyimino)fur-2-ylacetamido]-ceph-3-em-4- carboxylic acid as a light brown foam (5.08 g). This compound was treated with anisole (5.1 ml) and trifluoroacetic acid (13.3 ml) at room temperature for 20 min. The solvents were evaporated with the aid of toluene and the residual brown gum was triturated with ether.

The solution was evaporated to give the title compound as a light brown foam (4.48 g) vmox (Nujol) 3260-2200 (OH), 1788 (ss-lactam), 1720 (CO,H), 1680 and 1536 cm-' (CONH); # (DMSO-d6) 0.37 (1 H, d, J 8Hz, NH), 2.09 (1 H, s, 5'-H), 3.22(1 H, d, J 3 Hz, 3'-H), 3.33 (1 H, dd, J 2 and 3 Hz, 4'-H), 4.09 (1 H, dd, J 5 and 8 Hz 7-H), 4.75 (1 H, d J 5 Hz 6-H), 4.94 and 5.28 (' H. ABq. J 12 Hz, -CH2OAc). 6.38 (2 H, d, J 6 Hz, -S-CH2-), 7.93 (3 H. s, OCOCH3). 8.4-8.8 (4 H, m, cyclopropyl protons).

b) (6R, 7R) -3-A cetoxymeth 7-J(Z) -(1-carboxycyclopropyloxyimislo)Jitr-2-ylacetamido]- ceph-3-em-4-carboxvlic acid, disodiuni salt (6R,7R)-3-Acetoxymethyl-7-[(Z)-(1-carboxycyclopropyloxyimino)-fur-2- ylacetamido]ceph-3-em-4-carboxylic acid (984 mg) in acetone (15 ml) was treated portionwise with a solution of sodium octoate (700 mg) in acetone (10 ml). The mixture was stirred for 20 min. and the resulting precipitate was collected under nitrogen and washed with acetone. The damp filter cake was dried in vacuo. It was ground up and stirred with acetone (50 ml) for 30 min., then collected to give the title compound (758 mg), Bml.x (pH 6.0 phosphate buffer) 276 (E 19,300) and 233 nm (E10,600); vm.x (Nujol) 3190 (NH), 1765 (ss-lactam), 174() (acetate) and 1680 cm-' (carboxylate).

EXAMPLE 3 (6R,7R)-7-[Z-(1-carboxycyclopropyloxyimino)fur-2-ylacetamido]-3-(1-pyridirziummethyl) ceph-3-em-4-carboxykite, sodium salt A mixture of sodium iodide (13.0 g). water (3.9 ml) and pyridine (3.5 ml) was stirred at 80 and (6R, 7R)-3-acetoxymethyl-7-[Z-(1-carboxylcyclopropyloxyimino)fur-2- ylacetamidojceph-3-em-4-carboxvlic acid (3.3 g) was added. The mixture was stirred at 80 for 1 hr. and then cooled and diluted to about 100 ml with water. The pH of the solution was adjusted to 6.5 with dilute sodium hydroxide and the solution evaporated to small bulk under reduced pressure at < 4() . The residual solution was again diluted to about 100 ml, methyl isobutyl ketone (' drops) was added and the mixture stirred whilst being acidified to about pH 2 with dilute hydrochloric acid. The precipitated beige solid was filtered off and discarded and the filtrate extracted three times with ethyl acetate using a small aqueous backwash and the extracts discarded. The combined aqueous phases were re-adjusted to pH 6 with dilute sodium hydroxide solution and evaporated to small bulk and then diluted to 50 ml with water. The solution was applied to a column of XAD-2 resin (300 g) and eluted firstlv with water and subsequently with water containing 20% by volume of ethanol.

The fractions with the characteristic U.V. absorption of the required product were combined and evaporated to small volume. The solution was charcoaled, the pH re-adjusted to 6.5 and the solution freeze-dried to give the title compound (425 mg). #max (pH 6 phosphate buffer) 260 (e 16.700) and 280 nm (E 16.600); #(100 MHz:DO) 1.06. 1.43 and 1.94 (pyridinium protons). 2.34, 3.13 and 3.39 (fur-2-yl protons) 4.18 (d, J 4 Hz, 7 H) 4.73 (d. J 4Hz, 6 H). 4.49 and 4.63 (ABq. J 14 Hz, CH2No) 6.38 and 6.81 (ABq, J 18 Hz, 2-CH2) and 8.7(1 (broad d. -CH2CH2-).

EXAMPLE 4 (6R, 7R)-7-[(Z)-2-(1-carboxycycloprop-1-yloxyimino)-2-(fur-2-yl)acetamido]-3-[(5-methyl- 1 ,3,4-thiadiazol-2-vl) -thiomethyl]ceph-3-em-4-carboxylic acid To a solution of 2-(1-t-butoxycarbonylcycloprop-1-yloxyimino)-2-(fur-2-yl)acetic acid (298 mg) in dichloromethane (3.5 ml) at 0 was added triethylamine (0.14 ml) and then oxalyl chloride (0.09 ml) and then N,N-dimethylformamide (1 drop). The mixture was stirred at 0 to 5 for one hour and then evaporated to dryness. The residue was taken up in acetone (10 ml) and the filtered solution was added over 30 minutes to a stirred solution of (6R. 7R)-7-amino-3-[(5-methyl-1,3,4-thiadiazol-2-yl)thiomethyl]ceph-3-em-4-carboxylic acid (346 mg) and sodium hydrogen carbonate (210 mg) in water (20 ml) and acetone (10 ml) at 0 . The solution was stirred at 0 , rising to 100, for 15 minutes. It was then washed with ether and then covered with ether/ethyl acetate (1:1) (100 ml) and acidified with concentrated hydrochloric acid. and filtered. The organic layer was washed with brine, dried and evaporated to give (6R, 7R)-7-[(Z)-2-(1-t-butoxycarbonylcycloprop-1- yloxyimino)-2-(fur-2-yl)acetamido]-3-[(5-methyl-1,3,-3-[(5-methyl-1,3,4-thiadiazol-2-yl)thiomethyl]-ceph-3- esn-4-carboxvlic acid (574 mg) as a yellow foam. This compound (509 mg) was treated with anisole (0.1 ml) and trifluoroacetic acid (2 ml) at 24 for 5 minutes. The solvents were then evaporated with the aid of ethyl acetate, and the residue was partitioned between 3% sodium hydrogen carbonate solution and ethyl acetate. The aqueous phase was washed with ethyl acetate and then covered with ether/ethyl acetate (1:1) and acidified with concentrated hydrochloric acid. The organic phase was washed with brine and dried and evaporated to a pale brown foam (438 mg) which was triturated with ether/petrol (1:3) to give the title compound (354 mg) as an off-white solid, [aiD -1030(c 0.81. acetone); Xm.x (pH 6.0 phosphate buffer) 279 nm (E 25,200).

EXAMPLE 5 (6R, 7R)-7-[(Z)-2-(1-carboxvcycloprop-1-yloxyimino)-2-(fur-2-yl)acetamido[-3-(1- methyltetrazol-5-ylthiomethyl) -ceph-3-em-4-carboxyllc acid To a solution of 2-( l-t-butoxycarbonylcycloprop-1-yloxyimino)-2-(fur-2-yl)acetic acid (296 mg) in dichloromethane (3.5 ml) at 00 was added triethylamine (0.14 ml) and then oxalyl chloride (O.OY ml) and then N,N-dimethylformamide (1 drop). The mixture was stirred at 0 to 5 for one hour and then evaporated to dryness. The residue was taken up in acetone (10 ml) and the filtered solution was added over 30 minutes to a stirred solution of (6R. 7R)-7-amino-3-(1-methyltetrazol-5-ylthiomethyl)ceph-3-em-4-carboxylic acid (33U mg) and sodium hydrogen carbonate (210 mg) in water (20 ml) and acetone (10 ml) at () . The solution was stirred at 0 , rising to,O". for 15 min. and it was then concentrated to about half its volume by evaporation. The mixture was covered with ether/ethyl acetate (1:1) (100 ml) and acidified with concentrated hydrochloric acid (0.2 ml) and filtered. The organic layer was washed with brine. dried and evaporated to give (6R, 7R)-7-[(Z)-2-(1-t- butoxycarbonylcycloprop-1-yloxyimino)-2-(fur-2-yl)-acetam idoj-3- (I-methvltetrazol-5- ylthiomethyl)ceph-3-em-4-carboxylic acid (552 mg) as a pale yellow foam. This compound (453 mg) was treated with anisole (0.1 ml) and trifluoroacetic acid (2.0 ml) at 25 for 5 minutes. The solvents were then evaporated with the aid of ethyl acetate, and the residue was partitioned between 7czc aqueous sodium hydrogen carbonate and ethyl acetate. The aqueous phase was washed with ethvl acetate and then covered with ethyl acetate/ether (1:1) and acidified with concentrated hydrochloric acid. The organic phase was washed with brine and dried and evaporated to a paletbrown foam (417 mg) which was triturated with etherfpetrol (1:3) to give the title compound (315 mg) as an off-white solid, [&alpha;]D32 -72 (c 0.67, acetone): #max (pH 6.0 phosphate buffer) 278 nm (E 23,300).

EXAMPLE A This example illustrates the formulation of a pharmaceutical composition.

Dry pol1der for iiq'ecfl'on Sterile (6R, 7R)-3-acetoxymethyl-7-[(Z)-(1-carboxycyclopropyloxyimino)-fur-2- ylacetamido]ceph-3-cm-4-carboxylic acid. di-sodium salt is filled into glass vials, the claimed contents of each container being 500mg or 1.00g of the antibiotic as desired. Filling is carried out aseptically under a blanket of sterile nitrogen. The vials are closed using rubber discs or plugs held in position by aluminium sealing rings, thereby preventing gaseous exchange or ingress of micro-organisms. The product is intended for reconstitution with Water for Injections or other suitable sterile vehicle shortly before administration.

Claims (14)

WHAT WE CLAIM IS:

1. Compounds of the general formula

or. where the group Y carries a positive charge, compounds of the general formula (I) having the group - COO at the 4-position, [wherein Y is selected from: a) a group of formula

(wherein R' is hydrogen or a carbamoyl, carboxy, carboxy-methyl, sulpho or methyl group 1: b) a group of formula - SRi (wherein R' represents a 5- or 6-membered heterocyclic group having one or more heteroatoms selected from O, N and S): c) a group of formula - O.CO.R2 (wherein R2 is C,.7 alkyl): and d) a group of, formula - O.CO.AR' (wherein R' is hydrogen or Cl 7 alkyl and A is > O, > S or > NH, provided that when A is > O or > S. R' is not hvdrogenl and non-toxic derivatives thereof, the said compounds being syn isomers or existing as mixtures of syn and anti isomers containing at least 756Sc of the syn isomer.

'. A compound as claimed in claim l which is a syn isomer essentially free from the anti isomer.

3. Compounds as claimed in claim 1 wherein R' is a diazolyl, triazolyl, tetrazolyl, thiazolyl, thiadiazolvl. thiatriazolyl, oxazol I, oxadiazolyl, pyridyl or pyrimidyl group.

4. (6 R. 7R)-3-Carbamoyloxymethyl-7-(Z)-(1-carboxycyclopropyloxyimino)-fur-2-yl- acetamido]ceph-3-em-4-carboxylic acid and non-toxic derivatives thereof.

5. (6R, 7R)-3-Acetoxymethyl-7-[(Z)-(1-carboxycyclopropyloxyimino)-fur-2- ylacetamidojceph-3-em-4-carboxylic acid and non-toxic derivatives thereof.

6. (6R, 7R)-7-[(Z)-(1-Carboxycyclopropyloxyimino)-fur-2-ylacetamido]-3-( 1- pyridiniummethyl)ceph-3-em-4-carboxylate and non-toxic derivatives thereof.

7. (6R. 7R)-7-(Z)-2-(1-Carboxycycloprop-1-yloxyimino)-2-(fur-2-yl)acetamido]-3-[(5- methyl-1,3,4-thiadiazol-2-yl)thiomethyl] ceph-3-em-4-carboxylic acid and non-toxic derivatives thereof.

8. (6R. 7R)-7-[(Z )-2-( 1 -Carboxycycloprop-1-yloxyimino)-2-(fur-2-yl)acetamido]-3-(1 methyltetrazol-5-ylthiomethyl)ceph-3-em-4-carboxylic acid and non-toxic derivatives thereof.

9. A process for the preparation of a compound of formula I (as defined in claim 1) or a non-toxic derivative thereof, which comprises either (A) condensing a compound of the formula

[wherein B is > S or > SO (a- or ss-); R4 represents hydrogen or a carboxyl blocking group, the dotted line bridging the 2-. 3- and 4- positions indicates that the compound is a ceph-2-em or ceph-3-em compound; and Y is as defined in claim 1] or a salt or an N-silylated derivative thereof, with an acid of formula

(wherein RS is a carboxyl blocking group) or with an acylating agent corresponding thereto; or (B). reacting a compound of the formula

(wherein B and the dotted line are as hereinbefore defined; and Y' is a replaceable residue of a nucleophile) with a nucleophile seriving to introduce the group Y in formula I; whereafter, if necessary and/or desired in each instance, any of the following reactions (C) in any appropriate sequence, are carried out: i) conversion of a 2 isomer into the desired A isomer.

ii) reduction of a compound within B is > SO to form a compound wherein B is > S.

iii) deacylation of a 3-acyloxymethyl compound to form a 3-hydroxymethyl compound.

iv) acylation of a 3-hydroxymethyl compound to form a 3-acyloxymethyl compound, v) carbamoylation of a 3-hydroxymethyl compound to form an unsubstituted or substituted 3-cårbamovloxymethyl compound.

vi) removal of carboxyl blocking groups; vii) esterification of a 4-carboxyl group with a biologically acceptable ester group; and finallv (D) recovering the desired compound of formula I or a non-toxic derivative thereof, if necessary after separation of isomers.

10. A process as claimed in claim 9 wherein a compound (II) or an acid addition salt or N-silyl derivative thereof is condensed with an acid halide corresponding to the acid (111).

11. A process as claimed in claim 10 wherein the condensation is effected in the presence of an acid binding agent comprising a tertiary amine, an inorganic base or an oxirane.

12. A process as claimed in claim 9 wherein a compound (II) or an acid addition salt or N-silvl derivative thereof is condensed with an acid (III) in the presence of a carbodiimide.

carbonvldiimidazole or an isoxazolinium salt.

13. A pharmaceutical composition comprising an antibiotic compound as claimed in anv of claims 1 to 8. in a form adapted for use in human or veterinary medicine.

14. A composition as claimed in claim 13 in a form adapted for administration by injection.