Neue β‐Lactam‐Antibiotika. Über die Darstellung der «7‐Aminocephalocillansäure». Modifikationen von Antibiotika, 4. Mitteilung [1]

Abstract
‘7‐aminocephalocillanic acid’ 1, an intermediate for the preparation of new β‐lactam antibiotics was prepared by transforming the β‐lactam carbinol 2a to the phosphorane 9a through several steps. Oxydation of 9a with DMSO/Ac2O led directly to the cyclized ester 11a, which has been converted into 1 by known methods.