Aromatic substitution of 4‐phenylisothiazole

Abstract

Abstract Aromatic substitutions on 4‐phenylisothiazole by nitric acid, halogens, chlorosulfonic acid and acetic anhydride take place under relatively mild conditions to give predominantly para and ortho substitution on the benzene ring. By contrast, the 3‐isothiazolyl group has been shown to be meta directing. Several derivatives of 4‐phenylisothiazole are described.