Synthesis of functionalized penicillins and cephalosporins by photo-initiated bromination. A novel route to ampicillin and cephalexin from penicillin G

Article abstract of DOI:10.1016/0040-4020(84)85096-6

Potoinitiated bromination of the 1S-oxide ester 9, available in two stages from penicillin G6, gave the diastereometic bromides 10a and 10b. Both isomers have been utilized in further transformations to give the established antibiotics ampicillin 7 and cephalexin 8.