| 摘要 |
New thioloesters of the formula: <IMAGE> wherein R DEG represents hydrogen, alkyl, vinyl, cyanomethyl or a protecting radical, R' represents hydrogen or a protecting radical, R represents alkyl, L-2-amino-2-carboxyethyl, phenyl or various heterocyclic radicals, and their syn and anti isomers and mixtures thereof, and metal salts thereof and addition salts thereof with tertiary nitrogen-containing bases, are intermediates useful in the preparation of cephalosporins having anti-bacterial properties. |
