Preparation Of Ceph-3-Em Esters Unaccompanied By δ3To δ2Isomerization Of The Cephalosporin Derivatives

Abstract A synthesis of cephalosporin derivatives by reacting cephalosporin free carboxylic acid with alkyl halide in the presence of cesium carbonate and potassium carbonate is disclosed. δ3 to δ2 isomerization, a side reaction commonly reported in preparation of cephalosporin derivatives, was successfully eliminated The desired δ3 was obtained as a sloe product in the reaction.