| 摘要 |
6-Alpha and 6-beta-substituted penicillanic acid derivatives of the formula: <IMAGE> (I) wherein R is H or a conventional penicillin carboxy protecting group or an ester forming residue readily hydrolyzable in vivo and R1 is a perhaloalkyl group of from 1 to 4 carbon atoms wherein the halogen atoms are fluoro or chloro, undergo SN2 nucleophilic displacement with halide or azide ions with inversion of configuration at C-6 to yield the corresponding 6-beta or 6-alpha-halo- or azido-substituted product. |
