Reduction of cephalosporanic acids with chromium(II) salts: synthesis of 3-methylenecepham derivatives

Abstract

Cephalosporanic acid derivatives (I) were converted into 3-methylenecepham derivatives (II) on treatment with chromium(II) salts in aqueous media, and esters of 3-methylenecepham derivatives were readily isomerized to the 3-methyl-3-cephem derivatives (VII) under basic conditions.