Neue β‐Lactam‐Antibiotika. Über Derivate der 3‐Hydroxy‐7‐amino‐ceph‐3‐em‐4‐carbonsäure. Modifikationen von Antibiotika, 10. Mitteilung [1]

Abstract

3‐Hydroxy‐ceph‐3‐em‐esters 5 a–c, versatile intermediates for the preparation of new β‐lactam antibiotics, were obtained by ozonolysis of the corresponding 3‐methylidene‐esters 3 a–c. Reduction and elimination gave the 3‐unsubstituted ester 13; derivatives 16 a–c and 20–22 resulted from O‐alkylation. The 3‐methoxy‐esters 16 a–c were converted into the corresponding acids 23 a–d. Several other transformations of the β‐ketoester system are described.