Beiträge zur Chemie der β-Lactam-Antibiotika

Abstract

A reaction sequence for the preparation of 7-Amino-3-alkoxyceph-3-em-4-carboxylic acids 4 from natural penicillins is outlined. Key steps involve an ozonolysis and a novel type of cyclisation reaction (2 → 3). Products of the general structure 3 – not hitherto found in nature – have previously been prepared from Cephalosporin C [2].