Patent ID: 6800756
Filing Date: 2004-10-05
Classification: C07D

Abstract:
A process for the preparation of Ceftiofur acid of formula (I): and its pharmaceutically acceptable salts selected from sodium and hydrochloride salts, wherein Me represents methyl, the process comprising the steps of:(I) condensing an activated derivative of a compound of formula (III): wherein the activated derivative of the compound of formula (III) is selected from an acid halide, a mixed anhydride and an active amide, wherein Me represents methyl, and wherein X represents halogen atom selected from chlorine and bromine, with silylated derivative of 7-amino cephalosporin of formula (IV): wherein R represents p-methoxybenzyl, p-nitrobenzyl or diphenylmethyl group, in the presence of a solvent at a temperature in the range of âˆ’40Â° C. to 0Â° C. to produce a compound of formula (V): wherein R is as defined earlier,(ii) cyclising the compound of formula (V) with thiourea in the presence of water miscible solvent and sodium acetate at room temperature to produce cephalosporin compounds of formula (VI); wherein R and Me is as defined earlier,(iii) deesterifying the compound of formula (VI) to produce the compound of formula (I) using anisole/trifluoroacetic acid, phenol/trifluoroacetic acid or formic acid in the presence or absence of a solvent at a temperature in the range of 0Â° C. to 10Â° C. and, if desired, (iv) converting the compound of formula (I), to its pharmaceutically acceptable salt.