Förfarande för framställning av 7 -(skyddad amino eller acylamino)-3-metyl-1-karba-(1-detia)-(2 eller 3)-cefem-4-karboxylatföreningar

摘要

The invention provides a free radical process for preparing 1-carba(1-dethia)cephalosporin antibiotics with 2-substituted methylcephalosporin 1,1-dioxides wherein the substituent on the 2-methylene group is a free radical precursor group such as a phenyl or alkylseleno group. The latter dioxides are treated with a free radical initiator, e.g., a trialkyltin hydride or actinic radiation at 40 DEG C to 150 DEG C to provide the 1-carba-3-cephem and 1-carba-2-cephem products. The invention also provides free radical compounds formed as intermediates in the process.