Facile Synthesis of Benzothiazoles via Cascade Reactions of 2-Iodoanilines, Acid Chlorides and Lawesson’s Reagent

In the presence of Lawesson's reagent, metal-free one-pot cascade reactions of 2-iodoanilines with acid chlorides proceeded smoothly leading to 2-substituted benzothiazoles in good to excellent yields under mild conditions. Three steps were involved in the reaction process: (1) 2-iodoanilines reacted with acid chlorides to afford benzamides, (2) benzamides transferred to benzothioamides in the presence of Lawesson's reagent, and (3) intramolecular cyclization of benzothioamides generated the expected benzothiazoles.