The title compound has been prepared by two related procedures: Treatment of 3-hydroxy cephem derivative (I) with methanesulfonyl chloride and K2CO3 afforded mesylate (II), which was condensed with 2-mercapto-5-methyl-1,3,4-thiadiazole (III) in the presence of potassium tert-butoxide to give thioether (IV). The benzhydryl ester of (IV) was then deprotected by treatment with trifluoroacetic acid.
The reaction of 2-(2-sulfanylthiazol-4-yl)acetic acid ethyl ester (I) with ammonia and ammonium chloride gives the corresponding acetamide (II), which is condensed with the cephem methanesulfonate (III) by means of potassium tert-butoxide in dimethoxyethane to yield the diphenylmethyl ester (IV) of the target compound, which is finally hydrolyzed with trifluoroacetic acid and anisole.
In an alternative method, benzhydryl ester (V) was cleaved with trifluoroacetic acid to give carboxylic acid (VI). After protection of (VI) by means of trimethylsilyl acetamide, the triflate group was displaced by the potassium salt of mercapto thiadiazole (III) to furnish the title compound.