One-Pot Multi-Component Approach to the Synthesis of 1,4-Benzothiazines in Aqueous Media

A new and rapid synthetic strategy for the oxidative cyclocondensation of 2-aminobenzenethiol and 1,3-dicarbonyls has been developed in order to obtain 2,3-disubstituted 1,4-benzothiazines at ambient temperature and in aqueous media. A mechanism is presented to account for the formation of the products.