Synthesis of some substituted imidazo [5, 1-b] benzothiazoles

Cyclization of formylated and acetylated -substituted 2-aminomethylbenzothiazoles with phosphorus oxychloride gives 3-substituted imidazo 5, 1-b] benzothiazoles, and 3-substituted 1-methylimidazo 5, 1-b] benzothiazoles. Treatment of 2-benzothiazolyl-4-pyridylaminomethane with formic acid gives 3-(4-pyridyl) imidazo 5, 1-b] benzothiazole. 1-Mercapto-3-phenylimidazo 5, 1-b] benzothiazole is converted into 3-phenylimidazo 5, 1-b] benzothiazole by elimination of the mercapto group.