Acid-Catalyzed Synthesis of Aryl[4,5]isothiazoles through a Sulfenic Acid Pathway

Abstract

A new method to efficiently prepare 3-substituted aryl[4,5]isothiazoles by simply heating the starting materials with a catalytic amount of p-toluenesulfonic acid in toluene is reported. This simple procedure is well suitable for a variety of substrates that can tolerate substitution changes in the fusing aromatic ring, as well as at the 3-position. Substituted aryl rings of varying electronic properties and alkyl substitution eventually afford aryl[4,5]isothiazoles in high yields.