An Effective and Convenient Esterefication of Cephalospor in Derivatives by Using Quarternary Ammonium Salts as Catalysts

A method for preparing cephalosporin derivatives by reacting cephalosporin alkaline metal salts with organic halide in the presence of quarternary ammonium salts catalyst 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 sole product in the reaction.