Rapid, clean and efficient one-pot synthesis of thiopyrano[2,3-b]quinolines via domino Michael addition/cyclization reactions

Rapid and efficient one-pot synthesis of thiopyrano[2,3-b]quinolines is described from the reaction of 3-formyl-quinoline-2-thiones with acrylonitrile using economical organic base Et3N at room temperature. The reaction proceeded smoothly via domino Michael addition/cyclization reactions and did not require dry solvent, inert atmosphere and column chromatography purifications.