An alternative procedure for preparation of cefdinir.

Cefdinir, a broad spectrum third-generation cephalosporin for oral administration, was prepared by the following synthetic pathway: synthesis of diphenylmethyl 7beta-amino-3-vinyl-3-cephem-4-carboxylate hydrochloride from 7-aminocephalosporanic acid (7-ACA), preparation of sodium 2-(2-tritylaminothiazol-4-yl)-(Z)-2-(tritylhydroxyimino) acetate from ethyl acetoacetate, coupling of both intermediaries to obtain diphenylmethyl 7beta-[2-(2-tritylaminothiazol-4-yl)-(Z)-2-tritylhydroxyimino-3-vinyl-3-cephem-4-carboxylate and final cleavage of trityl and diphenylmethyl protective groups. This procedure allows to obtain better yields of cefdinir and to avoid the use of diketene during the synthesis of this antibiotic by the previously reported method.