GB1569254A - Preparation of a-(2 -acetonyloxy-4-oxo-azetidin-1-yl) glycolic acids and derivatives thereof and their use in preparing oxacephalosporins - Google Patents

Description

(54) PREPARATION OF a-(2- ACETONYLOXY4-OXO-AZETIDIN 1-YL) GLYCOLIC ACIDS AND DERIVATIVES THEREOF, AND THEIR USE IN PREPARING OXACEPHALOSPORINS wherein A and B are each independently hydrogen or an amino-protecting group or together form an amino-protecting group; X is hydroxy or a carboxy-protecting group; and Y is hydrogen or methoxy; provided that when A is hydrogen B cannot be hydrogen or phenylglycyl, which process comprises reducing a compound of the formula:

wherein A, B, X and Y are as defined above The amino-protecting group in the formula (12) can be acyl, silyl, sulfenyl or hydrocarbyl group or other aminoprotecting group containing up to 20 carbon atoms (including the corresponding groups in the side chains of natural or synthetic penicillins and cephalosporins).

The acyl groups which may be represented by A and/or B in the formula (12) include inorganic acyls such as carbonic acyl (e.g. alkoxycarbonyl, aralkoxycarbonyl or aryloxycarbonyl), sulfuric acyl, phosphoric acyl (e.g.

dialkoxyphosphinyl, dialkoxythiophosphonyl or alkoxyaminophosphoryl); and organic acyls such as alkanoyl, cycloalkanoyl, (71) We, SHIONOGI ss CO. LTD., a Japanese Body Corporate, of 12-3 Chome, Dbshi-Machi, Higashi-ku, Osaka, Japan, do hereby 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 the following statement:- The present invention relates to a process for the preparation of certain cr- (2fi- acetonyloxt - 4 - oxo - azetidin - 1 - yl) glycolic acids and derivatives thereof, and to the use of such compounds in the preparation of oxacephalosporins or mtermediates therefor.

So-called oxacephalosporins and oxapenicillins have been described by Christensen et at (Journal of the American Chemical Society, Volume 96, 7582 (1975)), and by Wolfe et al (Canadian Journal of Cliemistry, Volume 52, 3396 (1974)) and in published patent applications filed by these scientists.

According to the present invention there is provided a process for the preparation of a compound of the formula:

aralkanoyl, aroyl, alkylsulfonyl, arylsulfonyl or alkylphosphonyl. These groups can, where possible, be interrupted by a hetero atom in their skeleton or can be unsaturated or substituted by, for example, halogen (e.g.

fluorine, chlorine or bromine), a nitrogen function (e.g. amino, hydrazino, azido, alkylamino, arylamino, acylamino, alkylideneamino, acylimino, imino or nitro), or oxygen function (e.g. hydroxy, alkoxy, aralkoxy, aryloxy, acyloxy or oxo), a sulfur function (e.g. mercapto, alkylthio, aralkylthio, arylthio, acylthio, thioxo, sulfo, sulfonyl, sulfinyl, alkoxysulfonyl, or aryloxysulfinyl), a carbon function (e.g.

alkyl, alkenyl, aralkyl, aryl, carboxy, carbalkoxy, carbamoyl, alkanoyl, aroyl, aminoalkyl, aralkanoyl or cyano), or a phosphorus function (e.g. phospho or phosphoroyl). A and B can also be considered together as forming a diacyl group of dibasic acid (e.g. phthalyl, pyridine - 2,3 - dicarbonyl, maleoyl or succinoyl).

The hydrocarbon groups which may be represented by A and/or B can be easily removable aliphatic hydrocarbon groups containing from 1 to 20 carbon atoms (e.g.

alkyl, alkenyl, aralkyl or other aliphatic hydrocarbon groups) or easily removable mono-cyclic aromatic hydrocarbon groups (e.g. phenyl or pyrimidyl). These groups can, where possible be interrupted by a hetero atom in the skeleton thereof or can be unsaturated or substituted by a substituent (e.g. halogen or by nitrogen, oxygen, sulfur, carbon or phosphorus functions). A and B can also be considered together as forming a divalent hydrocarbon group (e.g. alkylene, aralkylene, alkylidene, aralkylidene, cr- halo- or alkoxy aralkylidene, diarylmethylidene or cycloalkylidene), which can, where possible, be interrupted by a hetero atom in the skeleton thereof or can be substituted by a substituent as cited above or can be unsaturated.

When group A is acyl and group B is a hydrocarbon group they can be combined together with the nitrogen atom bound to position 7 of the cephem ring to form a cyclic group (e.g. a 4- oxo- 3imidazolidinyl ring).

The silyl (e.g. trialkylsilyl) and sulfenyl (e.g. phenylsulfenyl or o nitrophenylsulfenyl) groups which may be represented by A and/or B are conventional amino protecting groups.

Representative acyl groups for A in the above formula (I) include, when B is a hydrogen, the following groups: 1) alkanoyl containing from 1 to 5 carbon atoms; 2) haloalkanoyl containing from 2 to 5 carbon atoms; 3) azidoacetyl; 4) cyanoacetyl; 5) acyl groups of the formula: Ar-CQQ'-CO- in which Q and Q' are each hydrogen or methyl; and Ar is phenyl, dihydrophenyl or a monocyclic heterocyclic aromatic group containing from I to 4 hetero atoms selected from nitrogen, oxygen and/or sulfur atoms, and may optionally be substituted by an alkyl or alkoxy group containing from 1 to 3 carbon atoms, chlorine, bromine, iodine, fluorine, trifluoromethyl, hydroxy, aminomethyl, cyano or nitro; 6) acyl groups of the formula: Ar-G-CQQ'-CO- in which G is oxygen or sulfur; and Ar, Q and Q' are as defined above; 7) acyl groups of the formula: Ar-CHT-CO- in which Ar is as defined above; and T is i) amino, ammonio, amino substituted by such conventional amino-protecting groups as benzyloxycarbonyl, alkoxycarbonyl containing from 1 to 4 carbon atoms, cyclopentyloxycarbonyl, cyclohexyloxycarbonyl, benzhydryloxycarbonyl, cyclopropylmethoxycarbonyl, methanesulfonylethoxycarbonyl, triphenylmethyl, 2,2,2, - trichloroethoxycarbonyl, guanidylcarbamoyl, optionally substituted ureido carbonyl, alkanoyl containing from 1 to 5 carbon atoms, pyrone - carbonyl, thiopyridonecarbonyl, pyridonecarbonyl, homo- or hetero-cyclic monocyclicaromatic acyl optionally substituted by hydroxy, lower alkanoyloxy containing from 1 to 3 carbon atoms, halogen, trifluoromethyl, or alkyl containing from 1 to 3 carbon atoms, amino-alkyl containing from 1 to 3 carbon atoms, or hydroxyalkyl containing from 1 to 3 carbon atoms, or amino protected in the forms of phthalimido or enamino derived from acetoacetates, acetylacetone, or acetonitrile, ii) hydroxy or acyloxy containing from 1 to 7 carbon atoms, iii) carboxy or alkoxycarbonyl containing from 2 to 7 carbon atoms, indanyloxycarbonyl, phenoxycarbonyl, or iv) azido, cyano, carbamoyl, alkoxysulfonyl, sulfo, aminosulfonyl or alkoxysulfonyl or HT combined represent hydroxyimino or alkoxyimino; 8)2 - sydnon - 3 - alkanoyl containing from 3 to 5 carbon atoms; 9) (2- or 4 - pyridon - 1 - yl)acetyl; 10) 5- aminoadipoyl, 5- aminoadipoyl protected at the amino group by alkanoyl containing from 1 to 10 carbon atoms, chloroalkanoyl containing from I to 5 carbon atoms or alkoxycarbonyl containing from 2 to 10 carbon atoms; or 5 aminoadipoyl protected at the carboxy group by benzhydryl, 2,2,2 - trichloroethyl, trialkylsilyl alkyl containing from I to 6 carbon atoms, nitrobenzyl or methoxybenzyl; and I 1) acyl groups of the formula: LO-CO- in which L is an easily removable optionally substituted hydrocarbon group containing from 1 to 8 carbon atoms (e.g. 2,2,2 trichloroethyl, isobornyl, tertiary butyl, 1 methylcyclohexyl, 2 - alkoxy-tertiary butyl, benzyl, p-nitrobenzyl or p-methoxybenzyl).

Alternatively, A and B considered together can represent a diacyl group derived from a polybasic carboxylic acid containing from 4 to 12 carbon atoms, alkylidene containing from 1 to 6 carbon atoms or arylmethylidene containing from 7 to 9 carbon atoms.

In the above, examples of Ar groups are furyl, thienyl, pyrryl, oxazolyl, isoxazolyl, oxadiazolyl, oxatriazolyl, thiazolyl, isothiazolyl, thiadiazolyl, thiatriazolyl, pyrazolyl, imidazolyl, triazolyl, tetrazolyl, phenyl, pyridyl, pyrimidyl, pyrazinyl, pyridazinyl, triazinyl and dihydrophenyl, each being optionally substituted by halogen, alkyl containing from 1 to 3 carbon atoms, hydroxy, aminomethyl or alkoxy containing from 1 to 3 carbon atoms.

The carboxy-protecting group which may be represented by X may contain up to 20 carbon atoms and can be an oxygen function such as, for example, alkoxy containing from 1 to 8 carbon atoms (e.g.

methoxy, methoxy or tertiary butoxy), aralkoxy containing from 7 to 20 carbon åsoms (e.g. benzyloxy, methoxybenzyloxy, nitrobenzyloxy, diphenylmethoxy or trityloxy, mono- or bi-cyclic aryloxy (e.g.

phenoxy or naphthyloxy), or organometaloxy (e.g. trimethylstannyloxy or trimethylsilyloxy), organic or inorganic acyloxy containing from 1 to 8 carbon atoms or metal-oxy groups I, II or III in the periodical table (e.g. sodiooxy, potassiooxy or magnesiodioxy); or X may be selected from sulfur functions such as those forming thiol ester or thiocarboxy groups; nitrogen functions such as those forming amides, hydrazides or azide groups; or, indeed, X may be selected from other carboxyprotecting groups. These groups can, where possible, be interrupted by a hetero atom in their skeleton, or can be unsaturated or substituted by a substituent such as those referred to above (e.g the nitrogen, oxygen, sulfur, carbon or phosphorus functions referred to above or halogen). Among carboxy-protecting groups X are those forming haloalkyl esters containing from 1 to 5 carbon atoms, acylalkyl esters containing from 2 to 10 carbon atoms, alkoxyalkyl- or amino-alkyl esters containing from 2 to 8 carbon atoms, acyloxyalkyl esters containing from 2 to 8 carbon atoms, carbalkoxyalkyl esters containing from 3 to 8 carbon atoms, the phenyl ester, aralkyl esters containing from 7 to 20 carbon atoms, esters with an oxime containing from 2 to 10 carbon atoms, N-alkoxyamide containing from 1 to 5 carbon atoms, imide with saccharin, imide with phthalimide, N,N' diisobutylhydrazide, metal salts, alkylamine salts containing from 1 to 6 carbon atoms, dicyclohexylamine salts or analogues thereof containing from 2 to 15 carbon atoms, or groups equivalent in effect to these groups (in the above, specified numbers of carbon atoms are for groups X).

Antibacterially preferred carboxyprotecting groups X include those which form acyloxymethyl esters, phenacyl esters, the benzaldoxime ester, the N,N dimethyl - aminoethyl ester, alkali metal salts, alkaline earth metal salts, acylated alkaline earth metal salts, and other groups equivalent in effect to these groups.

Preferred carboxy-protecting groups X include benzyhydryloxy, p-nitrobenzyloxy, p-methoxybenzyloxy, 2,2,2 trichloroethoxy and alkali metal-oxy.

In the accompanying drawing there is illustrated a reaction scheme showing the preparation of compounds of the formula (12) and the preparation therefrom of oxacephalosporins (15) and (16).

Among the reactions, the introduction of a propargyloxy group at position 2 of the azetidine ring to form compound (8) gives predominantly the 2,3-cis isomer (in the ratio of up to about 2:1 or more) in contrast to the cases where the 3-amino group is acylated where the reaction gives exclusively, or as the major product, the isomer having the 2,3-trans configuration leading to an ineffective final product (16) having, a 6p-hydrogen. In the present process, introduction of the propargyloxy group precedes acylation of the amino group (when the acylation step is included).

Furthermore, among procedures for the introduction of a propargyloxy group at position 2 of the azetidine ring to form a compound (8), that using zinc chloride is superior to that using silver tetrafluoroborate from the viewpoint of higher yields, or improved ratio of the desired isomer and expensive production.

The preparation of compounds (10) from compounds (9), which in turn are prepared from compounds (8) is somewhat analogous to the method of Neyler et al. (Journal of Chemical Society, 1973, 57) of the Beecham Group: and the preparation of compounds (15) from compounds (12) is somewhat analogous to the method of Neyler et al.

(Journal of Chemical Society, 1972, 229) of the Beecham Group; the above-listed references relating to l-thia instead of l-oxa cephalosporins. The preparation of compounds (16) from compounds (15) is a procedure which is conventional in the art.

A substantial number of the oxacephalosporins (15) are believed to be novel compounds. These may be designated by the formula:

wherein A and B are each independently hydrogen or an amino-protecting group or together form an amino-protecting group; X is hydroxy. or a carboxy-protecting group; and Y is hydrogen or methoxy; provided that when one of A and B is hydrogen the other is not hydrogen or acyl, and that A and B together do not form a substituted or unsubstituted aralkylidene group. It will be appreciated that the compounds of formulae (I) and (16) are also compounds of formula (15).

The compounds of formula (15) have been found to be very effective as antibacterial compounds against many bacteria and are superior to the corresponding l-thia or normal cephalosporins. The compounds can be used as bactericides for combatting bacterial infections in humans or other animals, or the decay of perishables: For human use, the compounds can be administered at a daily dosage rate of about 0.1 to about 5 g per man. Administration may be orally or by injection and may be in the form of any of the conventional pharmaceutical formulation types, and may be in admixture with suitable carriers if required.

The present invention includes a pharmaceutical or veterinary formulation which comprises a compound of formula (15) formulated for pharmaceutical or veterinary use and preferably in unit dosage form (e.g. tablets, capsules, pills, a suspension or solution or a powder).

The invention further provides a pharmaceutical or veterinary composition which comprises a compound of formula (15) and a pharmaceutically or veterinarily acceptable, respectively, diluent, carrier or excipient. Such compositions may be in unit dosage form.

The present invention also includes a method for preventing or inhibiting the growth of bacteria in an environment which comprises administering to the environment an effective amount of a compound of formula (15) or of a formulation or composition in accordance with the invention. The method may be used for the treatment of prevention of infection in an animal, for the prevention of decay in a perishable material or for the disinfection of a substance, an article or a building structure.

Examples are given by way of illustration of the present invention. Example 1 illustrates a process in accordance with the present invention and the remaining Examples illustrate the use of the compound prepared in Example 1 in the preparation of oxacephalosporins and intermediates therefor. In the NMR data the Hz values in parentheses are coupling constants.

Celite is a registered Trade Mark.

Example 1 Diphenylmethyl a - (2 - acetonyloxy 3ss - phenylacetamido - 4 - oxo - azetidin - 1 - yl)glycolate (12) To a solution of diphenylmethyl a - (2ss - acetonyloxy - 3ss - phenylacetamido - 4 - oxoazetidin - 1 - yl)glyoxalate (11) (2.312 g) in a mixture of methylene chloride (10 ml) and glacial acetic acid (10 ml) is added activated zinc powder (2.50 g) with stirring, and the mixture is stirred for 3 hours at room temperature. The reaction mixture is filtered through a layer of Celite which is washed with methylene chloride. the filtrate is washed with water, dried over sodium sulfate, and evaporated under reduced pressure to give the product (12) as a pale yellow foam (2.136 g) in the form of a mixture of epimers at position a. IR: sCHcl3 3425, 1675, 1505, 3350, 1785, 1740 cm-1.

Diphenylmethyl cr - (2ss - acetonyloxy - - phenylacetamido - 4 - oxoazetidin - 1 - yl glyoxalate (11), used above, may be prepared as follows: Into a solution of diphenylmethyl a - (2p acetonyloxy - 3ss - phenylacetamido 4 - oxoazetidin - 1 - yl) - a - isopropylideneacetate (10) (2,342 g; 4.33 mmole) in methylene chloride (40 ml) is introduced ozonized oxygen for 25 minutes at -78"C. Excess ozone is purged with nitrogen gas, and the mixture is mixed with dimethyl sulfide (3 ml), and stirred at -78"C for 30 minutes, and at room temperature for 30 minutes. The reaction mixture is mixed with three drops of acetic acid, washed with water, dried over sodium sulfate, and evaporated under reduced pressure to give the product (11) as a pale yellow foam (2.312 g).

IR: smHaCl3 3420, 1680, 1507, 1822, 1733, 1707 cm-1.

NMR: aCDC13 1 .87s3H, 3.55s2H, 5.30-5.57m2H, 6.85d(8Hz)lH, 4.22s2H, 6.93slH, 7.22+7.30m15H.

Diphenylmethyl a - (2ss - acetonyloxy 3/3 - phenylacetamido - 4 - oxoazetidin - 1 - yl) - a - isopropylideneacetate (10), as used above, may be prepared as follows: To a solution of diphenylmethyl a - [2ss (2 - propynyloxy) - 3ss - phenylacetamido 4 - oxoazetidin - 1 - yl] - a [isopropylideneacetate (9) (2.236 g; 4.28 mmole) in methanol (20 ml) is added water (2 ml.). To this solution is added saturated solution of mercuric sulfate in 10% sulfuric acid (0.8 ml), and the mixture is refluxed for 30 minutes. The reaction mixture is cooled, diluted with ethyl acetate, and washed with water. The ethyl acetate layer is dried over sodium sulfate, and concentrated under reduced pressure. Purification of the residue by chromatography over silica gel containing 10% water (100 g) using a mixture of benzene and ethyl acetate (2:1) as eluting solvent give the product (10) as a pale yellow foam (1.547 g; 66.9%).

IR: VmCHsCIx3 3425, 1676, 1510, 1774, 1735(shoulder), 1720 cm-'.

NMR: aCDb3 1.83s3H, 1.97s3H, 2.23s3H, 3.60s2H, 3.60+3.97q(8Hz)2H, 5.03d(4Hz)lH, 5.27dd(4;8Hz)lH, 6.50d(8Hz)lH, 6.93slH, 7.30+7.33m15H.

Diphenylmethyl a - [2,B - (2 propynyloxy) - 3,B - phenylacetamido - 4 oxoazetidin - 1 - yl) - a isopropyldideneacetate (9), as used above, may be prepared as follows: To a solution of diphenylmethyl a - [2p propynyloxy)- 3p - amino - 4 oxazetidin 1 1 - ylJa - isopropylideneacetate (8) (2.039 g; 5.04 mmole) in methylene chloride (15 mlj are added phenylacetyl chloride (1.00 ml 7.56 mmole) and pyridine (0.61 ml; 7.56 mmole) at 0 C with stirring. The mixture is stirred at 0 C for 30 minutes, mixed with ice water, and extracted with methylene chloride. The methylene chloride layer is washed with water, dried over sodium sulfate, and evaporated under reduced pressure. Purification of the residue by chromatography over silica gel containing 10% water (100 g) using a mixture of benzene and ethyl acetate (3:1) as eluting solvent gives the product (9) as a pale yellow foam (2.242 g; 85.1%).

IR: #maxCHCl3 3425, 1680, 1510, 3310, 2115, 1773, 1720 cm~'.

NMR:âCDC'3 1.98s3H, 2.25s3H, 2.23t(2.5Hz)lH, 3.58s2H, 3.95d.

Diphenylmethyl a - [2p - (2 propynyloxy) - 3ss - amino - 4 oxazetidin - 1 - yl] - a isopropylideneacetate (8), as used above, may be prepared as follows: 1) To a solution of crude diphenylmethyl a - [2p and 2a - chloro - 3ss - amino - 4 oxoazetidin - 1 - yl] - a - isopropylideneacetate (7) (0.95g) in a mixture of propargyl alcohol (3 ml) and tetrahydrofuran (2 ml) is added silver tetrafluroborate (0.79 g; 4 mmole), and the mixture is stirred at room temperature for 3 hours. The reaction mixture is diluted with benzene (50 ml), cooled to OOC, and stirred with a mixture of a 5% aqueous solution of sodium bicarbonate (10 ml) and saturated saline (5 ml). The mixture is filtered through a layer of Celite and the filtrate is separated.

The benzene layer is dried over sodium sulfate, concentrated under reduced pressure to give brown heavy oil, and purified by chromatography over silica gel containing 10 /,, water (50 g) to give the 2a propynyloxy derivative (134 mg) and the 2ss - propynyloxy derivative (134 mg) from factions eluted with a mixture of benzene and ethyl acetate (1:1).

2a - propynyloxy isomer: IR: smHCX13 3400, 3320, 2115, 1767, 1723 cm-'.

NMR:CDc'3 l.83br-s2H, l.98s3H, 2.22s3H, 2.33t(2.5Hz)lH, 4.07d(2.5Hz)2H, ca. 4.07dlH, 4.93d(1.0Hz)1H, 6.90s1H, 7.32sl0H.

2p - propynvloxy isomer: IR: PmHCxl3 3410, 3320, 2115, 1767, 1720 cm~'. NMR:aCDc'3 1.77br-s2H, 2.00s3H, 2.23s3H, 2.27t(2.5Hz)lH, 4.1 2d (2.5Hz)2H, 4.23d(4.0Hz)lH, 5.27d(4HZ) 1 H, 6.90slH, 7.32s10H.

2) To a cold solution of crude diphenylmethyl a - [2,B and 2a - chloro 3ss - amino - 4 - oxoazetidin - 1 - ylj - a - isopropylideneacetate (7) (0.95 g) in propargyl alcohol (5 ml) is added fused zinc chloride (818 mg; 6 mmole), and the mixture is stirred for 2 hours at room temperature.

The reaction mixture is diluted with benzene (50 ml), cooled to OOC, shaken with 5% aqueous sodium bicarbonate (30 ml), and stirred vigorously. The mixture is filtered through a layer of Celite to remove separated solid and the filtrate is separated.

The benzene layer is dried over sodium sulfate, and evaporated under reduced pressure to leave a brown heavy oil.

Purification of the residue by chromatography over silica gel containing 10% water (50 g) gives the starting material (107 mg), the 2a - propynyloxy isomer (106 mg) and the 2p - propynyloxy isomer (213 mg) from the fraction eluted with a mixture of benzene and ethyl acetate (1:1).

3) The reactions described in (1) and (2) above can be carried out using sodium iodide, stannous chloride and silver perchlorate in place of zinc chloride or silver tetrafluoroborate.

Crude diphenylmethyl a - [2,B and 2a chloro - 3/3 - amino - 4 - oxazetidin - I - yli - a - isopropylideneacetate, as used above, may be prepared as follows: To a solution of crude diphenylmethyl a (2/3 - methylthio - 3/3 - amino - 4oxoazetidin - 1 - yl) - a - isopropylidene acetate toluene - p - sulfonate salt (5)(13.48 g; 20 mmole) in methylene chloride (100 ml) is added a solution of chlorine in carbon tetrachloride (1.34 Mole/liter; 19.4 ml; 36 mmole) at-78 C. The mixture is stirred at -78 C for 20 minutes and at 0 C for 20 minutes, and evaporated under reduced pressure. The residue is triturated thrice in a mixture of ether and petroleum ether, and evaporated to give crude diphenylmethyl a - [2p and 2a - chloro - 3ss - amino - 4 oxoazetidin- I - yl] - - isoproylideneacetate toluene - p - sulfonate salt (6) as a yellow foam (13.43 g).

The product is treated with an aqueous solution of sodium bicarbonate and extracted with dichloromethane to give crude diphenylmethyl α - [2A and 2a - chloro - 3/3 - amino - 4 - oxoazetidin - I - yl]α - isopropylideneacetate (7) as a yellow brown heavy syrup (9.50 g) (from its NMR spectrum, the ratio of 2,B and 2a - chloro isomers was estimated to be about 4:1).

Separation of a part of the crude product (2.50 g) by chromatography over silica gel containing 10% water (100 g) gives, from the fraction eluted with a mixture of benzene and ethyl acetate (3:1), a (1:1) mixture of 2a and 2 - chloro isomers (120 mg), and pure 2,B - chloro isomer (480 mg).

2a - chloro isomer: NMR: aCDC13 1.98s3H, 2.25s3H, 2.83 br-s2H, 4.33d(1.2Hz)lH, 5.47d(1.2Hz)lH, 6.90slH, 7.30s10H (Estimated from NMR of mixture).

2ss - chloro isomer: IR: amHCx3 3425, 3370, 1787, 1730 cam-1.

NMR:8CDc'3 1.98s3H, 2.25s3H, 2.80br-s2H, 4.50d(4.0Hz)lH, 5.87d (4.0Hz)lH, 6.90slH, 7.30s10H.

EXAMPLE 2 Diphenylmethyl α - (2ss - acetonyloxy 3p - phenylacetamido - 4 - oxo - azetidin 1 - yl) - a - chloroacetate (13) To a solution of diphenylmethyl a - (2,B acetonyloxy - 3,B - phenylacetamido - 4 oxoazetidine - 1 - yl)glycolate (12) (2.136 g) anhydrous methylene chloride (20 ml) are added thionyl chloride (0.90 ml) and pyridine (0.33 ml) with stirring at OOC. After stirring for 1 hour at OOC, the mixture is poured into ice water, and extracted with ethyl acetate. The organic layer is washed with water, dried over sodium sulfate, and evaporated under reduced pressure to give the crude product (13) (2.251 g) as a brown foam in the form of a mixture of epimers at position a.

IR: VmCHaCxI3 3430, 1680, 1510, 1795, 1752, 1740(shoulder) cm-1.

EXAMPLE 3 Diphenylmethyl a - (2/3 - acetonyloxy - 3ss - phenylacetamido - 4 - oxo - azetidin 1 - yl) - a - triphenylphosphoranylidenenacetate (14) To a solution of crude diphenylmethyl a (2ss - acetonyloxy - 3/3 - phenylacetamido 4 - oxoazetidin - 1 - yl) - a - chloroacetate (13) (2.251 g) in anhydrous methylenechloride (20 ml) is added triphenylphosphino (1.50 g), and the mixture is refluxed for 4 hours under a nitrogen atmosphere. The reaction mixture is poured into ice water mixed with a 5% aqueous solution of sodium bicarbonate (20 ml), and extracted with methylene chloride. The organic layer is washed with water, dried over sodium sulfate, and evaporated under reduced pressure.

Purification of the residue by chromatography over silica gel containing 10% water (100 g) using a mixture of benzene and ethyl acetate (1:2) as eluting solvent gives the product (14) (2.328 g) as a yellow foam.

IR: #maxCHCl3 3430, 1675, 1507, 1770, 1735, 1628 cm-1.

EXAMPLE 4 Diphenylmethyl 1 - oxadethia - 3 methyl - 7- phenylacetamido - 3 cephem - 4 - carboxylate (15) A solution of diphenylmethyl a - (2ss - acetonyloxy - 3/3 - phenylacetamido 4 - oxoazetidin - 1 - yl) - a triphenylphosphoranylidene - acetate (14) (2.328 g) in anhydrous dioxane (30 ml) is refluxed for 64 hours under a nitrogen atmosphere, and evaporated under reduced pressure to remove dioxane. The residue is purified by chromatography over silica gel containing 10% water (150 g) using a mixture of benzene and ethyl acetate (1:1) as developing solvent to give the product (15) (1.103 g; 74.7%). Crystallization of the product from ether gives pure colorless crystals of compound (15). m.p. 106 107 C.

IR: #maxCHCl3 3428, 1679, 1510, 1792, 1721 cm-'. NMR: #CDC13 1.93s3H, 3.63s2H, 4.03s2H, 4.95d(4Hz)lH, 5.68dd (4.9Hz)lH, 6.67d(9Hz)lH, 6.92slH, 7.33+7.38ml5H.

[ai

EXAMPLE 5 1 - Oxadethia - 3 - methyl - 7 phenylacetamido - 3- cephem - 4carboxylic acid (16) To a solution of diphenylmethyl 1 - oxadethia - 3 - methyl - 7 phenylacetamido - 3 - cephem - 4carboxylate (15) (66 mg) in methylene chloride (3 ml) are added anisole (0.2 ml) and trifluoroacetic acid (0.2 ml) with stirring at OOC, and the mixture is stirred at 0 C for 2 hours. The reaction mixture is concentrated under reduced pressure to dryness, and the residue is dissolved in aqueous 5% sodium bicarbonate solution, and washed with ether. The aqueous layer is acidified with 2N - hydrochloric acid, and is extracted with ethyl acetate. The organic layer is washed with water, dried over sodium sulfate, and evaporated under reduced pressure. Crystallization of the residue from a mixture of methylene chloride and petroleum ether gives the product (16) (30 mg) as colorless crystals.

m.p. 180-182 C (with decomposition).

IR: vK8t 3404, 1778, 1650, 1536 cm-' EXAMPLE 6 Diphenylmethyl 1 - oxadethia - 7amino - 3 - methyl - 3 - cephem - 4 carboxylate (17) To a solution of diphenylmethyl 1 - oxadethia - 7 - phenyl - acetamido - 3 methyl - 3 - cephem - 4 - carboxylate (15) (600 mg; 1.243 mmole) in methylene chloride (15 ml) are added phosphorus pentachloride (518 mg; 2.486 mmole) and pyridine (0.181 ml; 2.486 mmole) at -200C.

and the mixture is stirred for 30 minutes at -200C and at room temperature for 45 minutes. To this solution is added methanol (10 ml) and the mixture is stirred for 30 minutes and then water is added to the mixture, and the mixture is stirred for 30 minutes at room temperature. The reaction mixture is concentrated under reduced pressure, neutralized with 5% sodium caitionate solution in the presence of ice, and extracted with ethyl acetate. The ethyl acetate layer is washed with water, dried over sodium sulfate, and evaporated under reduced pressure to give a pale yellow foam.

Purification of the foam by chromatography over silica gel containing 10% water (50 g) using a mixture of ethyl acetate and benzene (2: 1) as eluting solvent gives the product (17) as a colorless foam (367 mg).

IR: v ,t,HCx'3 3420, 3350, 1787, 1720 cm-'.

NMR: SCC'3 l.75s2H, 2.02s3H, 4.33s2H, 4.48d(4Hz)lH, 5.00d(4Hz)lH, 6.97slH, 7.40ml0H.

EXAMPLE 7 Diphenylmethyl 1 - oxadethia - 7 - N tertiary butoxycarbonyl - D - a - phenylglyinamido - 3 - methyl - 3 cephem - 4 - carboxylate (18) To a solution of diphenylmethyl I oxadethia - 7 - amino - 3 - methyl - 3 cephem - 4- carboxylate (17) (150 mg; 0.412 mmole) in a mixture of tetrahydrofuran (8 ml) and acetone (4 ml) are added N - tertiary butoxycarbonyl D - a - phenylglycine (155 mg; 1.5x0.412 mmole) and N - ethoxycarbonyl- 2 ethoxy - 1,2 - dihydroquinoline (152 mg; 1.5x0.412 mmole), and the mixture is stirred at room temperature for 14 hours. The reaction mixture is diluted with ethyl acetate, washed with water, hydrochloric acid, an aqueous solution of sodium bicarbonate and water, dried over sodium sulfate, and evaporated to give a pale yellow foam. Purification of the foam by chromatography over silica gel containing 10% water (30 g) using a mixture of benzene and ethyl acetate (2:1) gives the product (18) (248 mg).

IR: pmHCx3 3430, 1695, 1510, 1800, 1720 cm-'.

NMR: SCDCI3 l.43s9H, 1.98s3H, 4.18s2H, 5.00d(4Hz)lH, H, 5.27d(7Hz)lH, 5.65q(4;8Hz)lH, 5.67d(7Hz)lH, 6.77d(8Hz)lH, +7.4 aromatic H.

EXAMPLE 8 1 - Oxadethia - 7 - D - cr - phenylglycinamido- 3- methyl - 3cephem - 4 - carboxylic acid trifluoroacetate (19) To a solution of diphenylmethyl 1 - oxadethia - 7 - N - tertiary butoxycarbonyl - D - a phenylglycinamideo - 3 - methyl - 3 cephem - 4 - carboxylate (18) (246 mg) in methylene chloride (1.5 ml) are added anisole (0.7 ml) and trifluoroacetic acid (1.5 ml) and the mixture is stirred at 0 C for 80 minutes1 and at room temperature for 40 minutes, and concentrated under reduced pressure. The residue is treated with a mixture of ether and petroleum ether to give a powder of the product (19) as a pale yellow powder (180 mg). m.p.

decomposition takes place from 135"C.

IR: VmKaaxr 3410, 1775, 1675, 1527 cm~'.

NMR: aD2-Dcl l.97s3H, 4.33s2H, 5.10d(3.8Hz)lH, 32slH, 7.53s5H.

UV: AHsaXo 255 nm (:7080).

EXAMPLE 9 Diphenylmethyl 1 - oxadethia - 7 - D mandelamido - 3 - methyl - 3 - cephem 4 - carboxylate (20) To a solution of diphenylmethyl 1 - oxadethia - 7 - amino - 3 - methyl - 3 cephem - 4 - carboxylate (17) (71.6 mg; 0.196 mmole) in ethyl acetate (8 ml) is added successively a solution of sodium bisulfite in water (100 mg in 4 ml) and mandelic acid o - carboxyanhydride (52.5 mg; 1.5x0.196 mmole) with vigorous stirring at OOC. After stirring for 1 hour at room temperature, the mixture is diluted with ethyl acetate, washed with water, dried over sodium sulfate, and concentrated under reduced pressure. The thus-obtained pale yellow powder is purified by chromatography over silica gel containing 10% water (20 g) using a mixture of benzene and ethyl acetate (1:1) to give the product (20) (80.4 mg) IR: pmCHaCxI3 3425, 1695, 1510, 1797, 1727 cm1.

NMR: aCDC13 l.97s3H, 3.92br-slH, 4.20s2H, 5.00d(4Hz)lH,5.13slH, 5.63q(4.9Hz)lH, 6.98slH,+7.4 aromatic H.

EXAMPLE 10 1 - Oxadethia - 7 - D - mandelamido - 3 methyl - 3 - cephem - 4 - carboxylic acid (21) To a solution of diphenylmethyl 1oxadethia - 7 - D - mandelamido - 3methyl - 3 - cephem - 4 - carboxylate (20) (78.4 mg) in methylene chloride (2 ml) are added anisole (0.3 ml) and trifluroroacetic acid (0.3 ml) at OOC, and the mixture is stirred at 0 C for 30 minutes, and is evaporated under reduced pressure. The residue is dissolved in an aqueous solution to sodium bicarbonate, and washed with ether. The aqueous layer is acidified with hydrochloric acid, and extracted with ethyl acetate. The extract solution is washed with water, dried over sodium sulfate, and evaporated under reduced pressure to dryness. The residue is triturated in a mixture of ether and petroleum ether to give a pale yellow powder of the product (21) (25 mg). m.p. about 120"C to about 135 C.

IR: vmKxr 3400, 1781, 1712, 1673, 1524 cm- Compounds (17) and (19) (see above) In a manner similar to that described above for conversion of compound (8) to compound (16), the above compounds may be prepared with suitable protection in the form of, for example, N- tertiary butoxycarbonyl and O-formyl groups at the acyl groups.

EXAMPLE 11 7 - [D - 2 - (3 - Methylsulfonyl- 2oxoimidazolidin - 1 - yl - carbonamido) - phenylacetamidol - 3- methyl - 1 - oxadethia - 3 - cepham - 4 - carboxylic acid (22) To a solution of 7 - (D - 2 phenylglycinamido) - 3 - methyl - 1 - oxadethia - 3 - cephem - 4 - carboxylic acid trifluoroacetate (19) (63.5 mg) in a mixture of tetrahydrofuran (0.8 ml) and water (0.2 ml) is added triethylamine (40 l). To the stirred mixture at 0 C are added 3 - methylsulfonyl - 2 - oxoimidazolidine (83 mg) and triethylamine (40 y1). After stirring at room temperature for 15 minutes, the mixture is acidified with 2N hydrochloric acid, and mixed with water and ethyl acetate. The ethyl acetate layer is washed with water, and extracted with aqueous sodium bicarbonate. The aqueous layer is acidified with 2N - hydrochloric acid, and extracted with ethyl acetate. The ethyl acetate layer is washed with water, dried over sodium sulfate, and evaporated to remove ethyl acetate. Trituration of the residue in ether gives the title compound (22:23 mg) as a pale yellow powder. m.p.

about 150 1700C.

IR: sNUJo'3325, 1787, 1730, 1678, 1527, 1168 cm-'.

EXAMPLE 12 Diphenylmethyl 7 - (2 thienylacetamido)- 3 - methyl - 1 - oxadethia - 3 - cephem - 4 - carboxylate (23) To a solution of diphenylmethyl 7amino - 3 - methyl - 1 - oxadethia - 3 cephem - 4 - carboxylate (17)(85.5 mg; 0.235 mmole) in methylene chloride (3 ml) at 0 C are added 2 - thienylacetyl chloride (56.5 mg; 0.353 mmole) and pyridine (19 y1 0.353 mmole), and the mixture is stirred at 0 C for 1.5 hours. The reaction mixture is diluted with ethyl acetate, washed with water, dried over sodium sulfate, and evaporated under reduced pressure to remove ethyl acetate. Purification of the residue by chromatography over silica gel containing 10% water (20 g) using a mixture of benzene and ethyl acetate (2:1) as eluting solvent gives the title compound (23:111.9 mg) as a pale yellow foam.

IR: PmHcxl3 3420, 1792, 1722, 1680, 1505 cm-1.

NMR: CDC13 1.95s3H, 3.83s2H, 4.13s2H, 4.97d(4Hz)1H, 5.67dd(4;9Hz)1H, 6.62d(9Hz)lH, 6.98slH, 6.9-7.3m13H.

EXAMPLE 13 7 - (2 - Thienylacetamido) - 3 - methyl 1 - oxadethia - 3 - cephem -4 - carboxylic acid (24) To a solution of diphenylmethyl 7 - (2 thienylacetamido) - 3 - methyl - 1 oxadethia - 3 - cephem - 4 - carboxylate (23)(110 mg) in methylene chloride (3 ml) at 0 C are added anisole (0.3 ml) and trifluoroacetic acid (0.3 ml), and the mixture is stirred at 0 C for 30 minutes. The reaction mixture is evaporated under reduced pressure to dryness and triturated in a mixture of methylene chloride, ether and petroleum ether to give the title compound (24:51.5 mg) as a pale yellow powder. m.p.

180-185 C (with decomposition).

IR: sNaJ ' 3320, 1775, 1720, 1655, 1550 cm-5 EXAMPLE 14 Diphenylmethyl 7p - (a diphenylmethoxycarbonyl - a - phenylacetamido)- 3- methyl - 1 - oxadethia - 3 - cephem - 4 - carboxylate (25) To a solution of diphenylmethyl 7 amino - 3 - methyl - I - oxadethia - 3 cephem - 4 - carboxylate (85.6 mg; 0.235 mmole) in a mixture of tetrahydrofuran (6 ml) and acetone (3 ml) are added a - phenylmalonic acid monobenzyhydryl ester (245 mg; 0.705 mmole) and N ethoxycarbonyl - 2 - ethoxy - 1,2 dihydroquinoline (174 mg; 0.705 mmole), and the mixture is stirred at room temperature for 4 hours. The reaction mixture is diluted with ethyl acetate, washed with water, dilute hydrochloric acid, an aqueous solution of sodium bicarbonate and water, dried over sodium sulfate, and concentrated to give a heavy syrup (241 mg). Purification of the syrup by chromatography over silica gel containing 10% water (30 g) using a mixture of ethyl acetate and benzene (1:4) for elution, and trituration in a mixture of ether and petroleum ether gives the title compound (25) as a colorless foam (102.6 mg; 63%).

IR: ac13 3420, 3350, 1797, 1725, 1680, 1516 cm-1.

NMR: CDC'3 1.93s3H, 4.l0s2H, 4.68s2H, 4.90d(4Hz)lH, 5.60q(4; l0Hz)lH, 6.85s2H, ca. 7.25m.

EXAMPLE 15 78 - (a - Phenylmalonoamido)- 3 methyl - 1 - oxadethia - 3 - cephem - 4 carboxylic acid (26) To a solution of diphenylmethyl - 7p (a - diphenylmethoxy - carbonyl - a- phenylacetamido)- 3- methyl - 1 - oxadethia - 3 - cephem - 4 - carboxylate (25) (100 mg) in methylene chloride (3 ml) are added anisole (0.2 ml) and trifluoroacetic acid (0.2 ml) at OOC, and the mixture is stirred at OOC for 2 hours. The reaction mixture is concentrated under reduced pressure to leave a residue which is treated in a mixture of ether and petroleum ether to give the title compound (26) as an almost colorless powder 46 mg (89%). m.p.

115--1200C.

IR: pNujoj 3400-2300, 1770, 1720, 1630, 1525 cm~'.

EXAMPLE 16 Sodium 74 - (a - phenylmalonamido) - 3 - methyl - 1 - oxadethia - 3 - cephem - 4 carboxylate The product of Example 15 is dissolved in an aqueous solution of sodium bicarbonate (0.001 N) and diluted with water to give solutions for antibacterial assay for in vitro activity on Mueller Hinton agar plates. The result shows strong antibacterial activity for the product even against Gram negative bacteria including Pseudomonas resistant to usually available penicillins and cephalosporins.

Insofar as the present invention relates to a method for preventing or inhibiting the growth of bacteria in an environment, we make no claim herein to such a method for the prevention or treatment of disease in a human being.

Subject to the foregoing disclaimer: WHAT WE CLAIM IS: 1. A process for the preparation of a compound of the formula:

wherein A and B are each independently hydrogen or an amino-protecting group or together form an amino-protecting group; X is hydroxy or a carboxy-protecting group; and Y is hydrogen or methoxy: provided that when A is hydrogen B cannot be hydrogen or phenylglycyl, which process comprises reducing a compound of the formula:

wherein A, B, X and Y are as defined above.

2. A process as claimed in claim 1, wherein activated zinc powder is used as a reducing agent.

3. A process as claimed in claim 1 or claim 2, wherein the compound of formula (11) has been prepared by oxidative fission of a compound of the formula:

wherein A, B, X and Y are as defined in

Claims (1)

1. claim 1.

   4. A process as claimed in claim 3, wherein the compound formula (10) has been prepared by hydrating a compound of formula:

   wherein A, B, X and Y are as defined in claim 1.

   5. A process as claimed in claim 4, wherein the compound of formula (9) in which A and/or B are acyl groups has been prepared by acylation of a compound of formula:

   wherein X and Y are as defined in claim 1.

   6. A process as claimed in claim 5, wherein the compound of formula (8) has been prepared by reacting a compound of the formula:

   wherein X and Y are as defined claim 1 and Hal is a halogen atom, with a compound of the formula: HOCH2C=-CH in the presence of a halide ion trapping reagent.

   7. A process as claimed in any one of claims 1 to 4, wherein the amino-protecting group is any one of those specifically referred to hereinbefore.

   8. A process as claimed in any one of claims I to 7, wherein the carboxyprotecting group is any one of those specifically referred to hereinbefore.

   9. A process as claimed in claim 1 substantially as hereinbefore described in Example 1.

   10. A compound of the formula (12) as defined in claim 1 which has been prepared by a process as claimed in any one of the preceding claims.

   11. A process for the preparation of a compound of the formula:

   wherein A, B, X and Y are as claimed in claim 1 and Hal is a halogen atom, which process comprises halogenating a compound as claimed in claim 10.

   12. A process as claimed in claim 11 substantially as hereinbefore described in Example 2.

   13. A compound of the formula (13) which has been prepared by a process as claimed in claim 11 or claim 12.

   14. A process for the preparation of a compound of the formula:

   wherein A, B, X and Y are as defined in claim 1 which process comprises subjecting a compound as claimed in claim 13 to an ylide formation reaction.

   15. A process as claimed in claim 14 substantially as herein described in Example 3.

   16. A compound of the formula (14) which has been prepared by a process as claimed in claim 14 or claim 15.

   17. A process for the preparation of a compound of the formula:

   wherein A, B, X and Y are as defined in claim 1, which process comprises subjecting a compound as claimed in claim 16 to a Wittig reaction.

   18. A process as claimed in claim 17 substantially as hereinbefore described in Example 4.

   19. A compound of the formula (.15) which has been prepared by a process as claimed in claim 17 or claim 18.

   20. A process for the preparation of a compound of the formula:

   wherein A, B and Y are as defined in claim 1, which process comprises deprotecting the carboxy-protecting group in a compound of the formula (15) claimed in claim 19 wherein X is a carboxy-protecting group.

   21. A process as claimed in claim 20 substantially as hereinbefore described in Example 5.

   22. A compound of the formula (16) which has been prepared by a process as claimed in claim 20 or claim 21.

   23. A process for converting a compound as claimed in claim 19 into another cephem compound, wherein the conversion is effected in a manner substantially as herein before described in any one of Examples 6 to 16.

   24. A compound which has been prepared by a process as claimed in claim 23.

   25. A pharmaceutical or veterinary formulation which comprises a compound as claimed in any one of claims 19, 22 and 24 formulated for pharmaceutical or veterinary use, respectively.

   26. A formulation as claimed in claim 25 and in unit dosage form.

   27. A pharmaceutical or veterinary composition which comprises a compound as claimed in any one of claims 19, 22, and 24 and a pharmaceutically or veterinarily acceptable, respectively, diluent, carrier or excipient.

   28. A composition as claimed in claim 27 and in unit dosage form.

   29. A formulation as claimed in claim 25 or a composition as claimed in claim 27 in the form of a tablet, a capsule, a pill, a suspension, a solution or a powder.

   30. A composition as claimed in claim 27 and substantially as hereinbefore described in Example 16.

   31. A method for preventing or inhibiting the growth of bacteria in an environment, which method comprises administering to the environment an effective amount of a compound as claimed in any one of claims 19, 22, and 24 of a formulation as claimed in any one of claims 25, 26 and 29, or of a composition as claimed in any one of claims 27, 28 and 30.

   32. A method as claimed in claim 31 when used for the treatment or prevention of an infection in an animal.

   33. A method as claimed in claim 31 when used for the prevention of decay in a perishable material.

   34. A method as claimed in claim 31 when used for the disinfection of a substance, an article or a building structure.

   35. A perishable material which has been preserved by a method as claimed in claim 33.

   36. A substance, an article or a building structure which has been disinfected by a method as claimed in claim 34.