Methanol → Benzhydryl 7-amino-3vinyl-3cephem-4-carboxylate hydrochloride

Beteiligte Stoffe

Reaktionsschritte

To a suspension of phosphorus pentachloride (15.5 g) in methylene chloride (200 ml) was added dropwise pyridine (5.9 g) at 5° to 10° C. with stirring, and the stirring was continued at 5° C. for 20 minutes. Thereto was added at a time benzhydryl 7-(5-benzamido-5-benzhydryloxycarbonylpentanamido)-3-vinyl-3-cephem-4-carboxylate (20 g) at 5° C., and the mixture was stirred at the same temperature for 2 hours. To the reaction mixture was added gradually methanol (120 ml) at -40° C., followed by stirring at -20° to -10° C. for an hour. Removal of the solvent gave a residue, to which ethyl acetate (300 ml) and water (50 ml) were added. The mixture was stirred under ice-cooling for a while, and the precipitated crystals were collected by filtration and then washed with isopropyl alcohol to obtain benzhydryl 7-amino-3-vinyl-3-cephem-4-carboxylate hydrochloride (8.4 g), mp 180°-195° C. (dec.).

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