This compound can be prepared by the route shown in scheme: Reaction of chlorodifluoromethane (Freon 22) with ethyl thioglycolate (II) in the presence of ethanolic sodium ethoxide gives ethyl 2-(difluoro-methylthio)acetate (III), which is hydrolyzed with aqueous potassium hydroxide to yield 2-(difluoromethylthio)acetic acid (IV). Substitution of diphenylmethyl-7alpha-benzamido-3-chloromethyl-1-oxa-3-cephem-4-carboxylate (V), an important intermediate for production of latamoxef, with 1-(2-hydroxyethyl)-1H-tetrazole-5-thiol (VI) in the presence of sodium methoxide, followed by protection of the hydroxyl group by means of p-methylbenzyl chlorocarbonate (VII) and pyridine, gives diphenylmethyl 7alpha-benzamido-3-[[1-[2-(p-methylbenzyloxycarbonyloxy)ethyl-1H-tetrazol-5-yl]thiomethyl]-1-oxa-3-cephem-4-carboxylate (VIII). Methoxylation of (VIII) with tert-butylhypochlorite and lithium methoxide, followed by the conventional side-chain cleavage with phosphorus pentachloride pyridine methanol, affords diphenylmethyl 7beta-amino-7alpha-methoxy-3-[[1-[2-(p-methylbenzyloxycarbonyloxy)ethyl]-1H-tetrazol-5-yl]thiomethyl]-1-oxa-3-cephem-4-carboxylate (X). This amine (IX) is condensed with the acid (IV) by means of phosphoryl chloride and pyridine fo yield diphenyl-methyl 7beta[2-(dfluoromelhylthio)acetamido]-7alpha-methoxy-3-[[1-[2-(p-methylbenzyloxycarbonyloxy)ethyl]-1H-tetrazol-5 yl)thiomethyl]-1-oxa-3-cephem 4-carboxylate (X), which undergoes deprotection with stannic chloride and anisole, neutralization with aqueous sodium bicarbonate and lyophilization giving the sodium salt (XI).

This compound can be prepared by the route shown in scheme: Reaction of chlorodifluoromethane (Freon 22) with ethyl thioglycolate (II) in the presence of ethanolic sodium ethoxide gives ethyl 2-(difluoro-methylthio)acetate (III), which is hydrolyzed with aqueous potassium hydroxide to yield 2-(difluoromethylthio)acetic acid (IV). Substitution of diphenylmethyl-7alpha-benzamido-3-chloromethyl-1-oxa-3-cephem-4-carboxylate (V), an important intermediate for production of latamoxef, with 1-(2-hydroxyethyl)-1H-tetrazole-5-thiol (VI) in the presence of sodium methoxide, followed by protection of the hydroxyl group by means of p-methylbenzyl chlorocarbonate (VII) and pyridine, gives diphenylmethyl 7alpha-benzamido-3-[[1-[2-(p-methylbenzyloxycarbonyloxy)ethyl-1H-tetrazol-5-yl]thiomethyl]-1-oxa-3-cephem-4-carboxylate (VIII). Methoxylation of (VIII) with tert-butylhypochlorite and lithium methoxide, followed by the conventional side-chain cleavage with phosphorus pentachloride pyridine methanol, affords diphenylmethyl 7beta-amino-7alpha-methoxy-3-[[1-[2-(p-methylbenzyloxycarbonyloxy)ethyl]-1H-tetrazol-5-yl]thiomethyl]-1-oxa-3-cephem-4-carboxylate (X). This amine (IX) is condensed with the acid (IV) by means of phosphoryl chloride and pyridine fo yield diphenyl-methyl 7beta[2-(dfluoromelhylthio)acetamido]-7alpha-methoxy-3-[[1-[2-(p-methylbenzyloxycarbonyloxy)ethyl]-1H-tetrazol-5 yl)thiomethyl]-1-oxa-3-cephem 4-carboxylate (X), which undergoes deprotection with stannic chloride and anisole, neutralization with aqueous sodium bicarbonate and lyophilization giving the sodium salt (XI).