Sulphides, sulphoxides, and sulphones derived from salicyclic acids

Abstract

Methanesulphenyl chloride with 3-t-butyl-6-methylsalicylic acid (7) and pyridine affords the 5-chloro (9), 5-methylthio (10), and 5-pyridinium (11) derivatives. Arenesulphenyl chlorides similarly give chloro and arylthio derivatives. Sulphenylation is favoured by the use of sterically hindered bases. Less substituted salicylic acids give aryl sulphones by Friedel–Crafts reactions, and alkyl sulphides, sulphoxides, and sulphones by chlorosulphonation, reduction to the thiol, alkylation, and oxidation. Some electrophilic substitutions of these compounds are described.