To a solution of phosphorus pentachloride (7.87 g) in ethylene chloride (47.75 ml) was added pyridine (2.99 g) at 5° to 6° C. After stirring for 30 minutes, to the mixture was added benzhydryl 7-(5-benzhydryloxycarbonyl-5-ethoxycarbonylaminopentanamido)-3-vinyl-3-cephem-4-carboxylate (9.75 g). After stirring for 2 hours at 5° to 6° C. and cooling to -30° to -20° C., the mixture was treated with 2-methoxyethanol (7.67 ml) for 1.5 hours and then with water (10 ml) for an hour. The precipitates were collected by filtration and washed with ethyl acetate and diisopropyl alcohol to give benzhydryl 7-amino-3-vinyl-3-cephem-4-carboxylate hydrochloride (1.99 g).
