4H-3,1-benzothiazine-2-thione, carbon disulfide, (E)-3-(2-aminoaryl)acrylate, (E)-3-(2-aminoaryl)acrylonitrile, Michael addition, Science, Organic chemistry, QD241-441

A new simple and efficient method to construct ring-fused 4-alkyl-4H-3,1-benzothiazine-2-thione derivatives has been developed from carbon disulfide and (E)-3-(2-aminoaryl)acrylates or (E)-3-(2-aminoaryl)acrylonitriles under mild conditions, without the need for a metal catalyst. The newly developed method tolerates a wide range of substrates in moderate to excellent yields. Moreover, this method is advantageous over previous ones for the easy synthesis of reactants.