PROCESS FOR THE PREPARATION OF CEPHALOSPORIN ANTIBIOTIC

摘要

A process for the preparation of cephalosporin antibiotic of the formula (I) wherein R1 represents hydrogen, trityl, etc,; R3 is carboxylate ion or COORd, where Rd represents hydrogen, ester or a counter ion which forms a salt; R4 represents H, OCH3, OCOCH3, =CH2, OCONH2, etc, which comprises: (i) condensing the activated derivative of the formula (III) where X represents halogen atom, with 7-amino cephalosporin derivative of the formula (XV) wherein R represents hydrogen, lower alkyl, etc, in the presence of a solvent at a temperature in the range of -50 °C to +50 °C to produce a compound of formula (XVI) ii) maintaining the pH in the range 5.0-10.0 using an inorganic base, iii) cyclizing the compound of formula (XVI) with thiourea to produce compound of formula (I).