PROCEDURE FOR THE PRODUCTION OF CEFEMDERIVAT

摘要

Prodn. of cephem derivs. of formula (I) and their easily cleaved esters or salts, uses cephalosporin C derivs. of formula (II) (or its esters or salts) as starting material. (Ac = an acyl gp. R = OCOCH3 or SHet, where Het is a heteroaromatic residue). The process comprises subjecting (II) to (a) silylation; (b) iminohalogenation; (c) iminoetherification; (d) acylation and (e) hydrolysis. Depending on nature of Ac, (I) are antibacterials or intermediates. No protection of the prim. NH2 in (II) is necessary, so fewer stages are required and the intermediates do not have to be isolated. (I) are obtd. in good yields and high purities.