Benzoisothiazole is a benzo derivative of isothiazole, which is a kind of bicyclic aromatic organic compound, which is formed by fusion of a six-membered benzene ring and a five-membered heterocyclic ring composed of two adjacent heteroatoms, N and S. Benzoisothiazoles are important pharmaceutical intermediates. Some benzoisothiazole derivatives exhibit potent cytotoxic and antitumor activities.
Benzoheterocycles are heterocycles which are fused with a benzene ring. Coumarone, thianaphthene, benzopyridine, isoquinoline, and dibenzopyridine all belong to this class of compounds.