ISOLATION AND STRUCTURE ELUCIDATION OF A NOVEL PRODUCT OF THE ACIDIC DEGRADATION OF CEFACLOR

The acidic aqueous degradation of cefaclor, an orally administered cep halosporin antibiotic, has been investigated. The most prominent peak in the high-performance liquid chromatography profile of a degraded so lution of cefaclor was isolated by preparative high-performance liquid chromatography. Mechanistically, the formation of this degradent from cefaclor involves a condensation of two cefaclor degradation products in which both products have undergone contraction from a six-membered cephem ring to a five-membered thiazole ring, presumably via a common episulfonium ion intermediate.