New simple synthesis of ring-fused 4-alkyl-4<i>H</i>-3,1-benzothiazine-2-thiones: Direct formation from carbon disulfide and (<i>E</i>)-3-(2-aminoaryl)acrylates or (<i>E</i>)-3-(2-aminoaryl)acrylonitriles
A new simple and efficient method to construct ring-fused 4-alkyl-4H-3,1-benzothiazine-2-thione derivatives has been developed from carbondisulfide 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