A procee for preparing 3-unsubstituted cephalosporins and 1-carba(dethia) cephalosporins

摘要

A process for preparing 7 beta -acylamino (or 7 beta -protected amino)-3-H-1-carba(1-dethia)-3-cephem-4-carboxylic acid esters and the corresponding cephalosporins is provided. 7 beta -Acylamino (or 7 beta -protected amino)-3-halo (or 3-sulfonyl ester)-1-carba(dethia)-3-cephem carboxylic acid esters and the corresponding cephalosporins are reduced with Pd(O) and a tetra-C2-C6 alky stannane and, when a 3-sulfonyloxy ester is reduced, the process is carried out in the presence of an alkali metal halide. 3-Sulfonyloxy-3-cephem esters such as 3-mesylate, 3-tosykate and 3-triflate are employed.