Oxidation of some penicillins and other sulphides by use of a polymer-supported peroxy-acid

Abstract

The oxidation of sulphides by a resin containing peroxy-acid residues has been investigated. Tetrahydrothiophen and L-methionine react with 1 equiv. of reagent to give both sulphoxide and sulphone. High yields of sulphone are obtained when more than 2 equiv. of reagent are used. Penicillins and deacetoxycephalosporins react with 1.1–1.3 equiv. of polymeric peroxy-acid to give high yields of sulphoxide, and in several instances removal of the polymer at the end of the reaction period left a solution of just the sulphoxide. Where mixtures of epimeric sulphoxides were formed, the polymeric reagent showed a stereoselectivity similar to that of monomeric reagents. Some success has been achieved in recycling the spent resin reagent. Penicillin G is efficiently oxidised to its S-oxide when a solution in acetone is passed down a column of peroxy-acid resin at 40 °C.