In 70 ml of dimethylsulfoxide was dissolved 11.9 g (0.02 mole) of (Z)-2-(2-tritylamino-4-thiazolyl)-2-(hydroxyimino)acetic acid benzhydryl ester and after adding thereto 2.76 g of a powder of potassium carbonate and 1.7 g (0.0225 mole) of of chloroacetonitrile, the mixture was allowed to react overnight at room temperature. After the reaction was over, the reaction mixture was poured into 150 ml of ice water, the product was extracted first with 150 ml of ethyl acetate and then with 100 ml of ethyl acetate. The organic layers were collected, and washed twice with 50 ml of water and then with 10 ml of a saturated aqueous sodium chloride solution. The ethyl acetate layer obtained was dried over anhydrous magnesium sulfate, and the solvent was distilled off to provide a caramel. To the caramel was added 100 ml of ethyl ether to powder the caramel. 11.5 g (yield: 90.7%) of (Z)-2-(cyanomethyloxyimino)-2-(2-tritylamino-4-thiazolyl)acetic acid benzhydryl ester was obtained. ##STR15##
