Synthesis of O-vinyl oximes and derived penicillins using organoselenium intermediates

Abstract

A synthetic scheme is described for the conversion of ethyl 2-hydroxyimino-3-oxobutyrate 3 into ethyl 2-(2-aminothiazol-4-yl)-2-vinyloxyiminoacetate 9via ethyl 2-{[2-(2-nitrophenylselenyl)ethoxy]imino}-3-oxobutyrate 5. The analogous 2-(1 -phenylvinyloxyimino)22 and 2-(isopropenyloxyimino)23 esters were obtained similarly from ethyl 2-hydroxyimino-3-oxobutyrate 3 or the corresponding methyl ester 25 by routes involving the epoxide-derived β-hydroxy selenides 2-(2-nitrophenylselenyl)1-phenylethanol 14 and 1-(2-nitrophenylselenyl)propan-2-ol 15. Subsequently ethyl 2-(2-aminothiazol-4-yl)-2-vinyl- 9 and 2-(1-phenylvinyl)-oxyiminoacetate 22 were successfully converted into the corresponding 6β-(substituted acetamido)penicillin sodium salts 11 and 24.