The Reaction of some Isothiazolium Salts with Sulfur in Pyridine

Abstract

A variety of N-methyl and N-phenylisothiazolium salts has been synthesized and treated with sulfur in boiling pyridine. The products have been examined by chromatography and their structures determined. While 5-unsubstituted isothiazolium salts appear to give the corresponding isothiazoline-5-thiones, 3-unsubstituted salts give either the corresponding isothiazoline-3-thiones if the nitrogen is alkyl substituted, or 1,2-dithiole-3-imines if the nitrogen is aryl substituted. N-Alkyl compounds also give dealkylated products, and dithiolethiones are also found. The initial stages in the reaction appear to involve deprotonation of the isothiazolium salt.