Cephalosporin degradations

Abstract

The acidic aqueous degradation of the 7.alpha.-aminophenylglycinamido-containing cephalosporin cephalexin was examined. Two major degradation products were isolated and characterized: 3-formyl-3,6-dihydro-6-phenyl-2,5(1H,4H)-pyrazinedione and 3-hydroxy-4-methyl-2(5H)-thiophenone. By carrying out the reaction in 18O-enriched H2O, the intramolecular nature of the cephalexin degradation was demonstrated.