One-Pot, Four-Component Synthesis of Novel Spiro[indeno[2,1-b]quinoxaline-11,4′-pyran]-2′-amines

Abstract

A one-pot, four-component reaction for the efficient synthesis of novel spiro[indeno[2,1-b]quinoxaline-11,4′-pyran]-2′-amines by using InCl3 is described. The syntheses are achieved by reacting ninhydrin with 1,2-diaminobenzenes to give indenoquinoxalines, which are trapped in situ by alkyl malonates and various α-methylencarbonyl compounds through cyclization, providing multifunctionalized spiro-substituted indeno[2,1-b]quinoxaline-11,4′-pyran-2′-amines.