Copper-Catalyzed Synthesis of 2-Imino-1,2-dihydroquinolines and -thiochromenes

Significance

A copper-catalyzed one-pot three-component reaction of aryl sulfonyl azides, terminal aryl alkynes and acetyl or benzoyl anilines to yield 2-imino-1,2-dihydroquinolines is reported. Subjecting 2-aminobenzaldehyde to the same conditions did not lead to the desired product. The yields were good to excellent and the substrate scope was fairly well studied. The resulting compounds are stable to tautomerization under acidic and basic conditions. Using the potassium salt of 2-mercaptobenzaldehyde as substrate led to 2-imino thiochromenes in excellent yields but the scope of this transformation was inadequately studied.