Transformations of penicillins. Part VI. Preparation and reactions of thiosulphonate S-esters derived from penicillin S-oxides

Abstract

The sulphenic acids derived by heating penicillin sulphoxides react with arenesulphinic acids to form the corresponding arenethiosulphonate S-esters. These esters are themselves versatile derivatives and react with nucleophiles to form the corresponding sulphides, liberating the arenesulphinic acid. This two-step process greatly extends the range of substituents that can be introduced onto the penicillin sulphur atom after opening of the thiazolidine ring. A novel reaction was obtained with the thiosulphonate ester (2; R = Me) and sodium azide, which gave the symmetrical disulphide (6).