A group of N-alkenylbenzthionamides and acetthionamides have been prepared from the corresponding isothiocyanates and Grignard reagents. Allylic N-alkenylthionamides cyclize when treated with acidic catalysts such as aluminum chloride, but not with benzoyl peroxide. The position of cyclization follows the Markovnikov rule with an apparent slight preference for thiazoliies over dihydrothiazines when other factors are equal.
