Green approach to highly functionalized thiopyrano derivatives via domino multi-component reaction in water

Abstract

A green, operationally simple and highly efficient one pot three-component approach for the synthesis of thiopyrano[2,3-b]indole-3-carbonitrile, thiopyrano[2,3-b]thiochromene-3-carbonitrile and dihydrothiochromeno[2,3-b]thiochromene derivatives has been developed by the domino reaction of indoline-2-thione or 4-hydroxy-2H-thiochromene-2-thione with aldehyde and malononitrile or dimedone in water at 100 °C. The significant advantages of this protocol are highlighted by short reaction time, excellent yields and formation of three new bonds and a stereocenter in one operation from easily available starting materials.