Neue β-Lactam-Antibiotika. Cephem-Derivate mit elektronenanziehenden Substituenten in 3-Stellung. Modifikationen von Antibiotika. 14. Mitteilung
作者:Heinrich Peter、Beat Müller、Hans Bickel
DOI:10.1002/hlca.19750580825
日期:1975.11.5
New β‐lactam antibiotics. Cephem derivatives with electron withdrawing substituents at position 3Oxidation of the 3‐formyl‐2‐cephem compound 1 according to Corey [6] gave 2‐cephem‐3‐carboxylic esters 4a, b, c (Scheme 1), which proved to be useful intermediates for the synthesis of cephalosporins bearing in position 3 a methoxycarbonyl group (10a, b, c, d / Scheme 2) or a carboxy group (20, 25, 30/Schemes 3, 4). The 3‐formyl‐3‐cephem compounds 31a, b could be transformed into cyano‐ (33a) or methoxyiminomethyl‐ (36a, c, d) cephems (Scheme 5), which represent further examples of cephalosporins with electron withdrawing groups in position 3.