Visible-Light-Mediated Synthesis of 4 H -benzo[1,4]thiazin-2-amines and 3,4-Dihydroquinoxalin-2-amines: An Efficient and Metal Free Route to C–S, C–N Bond Formation

An efficient and practical synthesis of benzothiazine by visible-light-mediated free radical reaction has been developed. This protocol provides a new, facile, eco-friendly strategy to construct benzothiazine and quinoxaline derivatives via formation of C–S and C–N bonds under metal-free condition. This synthesis has been performed under visible light illumination in aqueous ethanol at room temperature using aromatic aldehyde, o -aminothiophenol and isocyanide as reactants. Graphical Abstract