Hypervalent iodine-mediated synthesis of 1-aryl-4-methyl-1,2,4-triazolo[4,3-a]quinoxalines by oxidative cyclization of arene carbaldehyde-3-methylquinoxalin-2-yl hydrazones

摘要

Arene carbaldehyde-3-methylquinoxalin-2-yl hydrazones (2) obtained by the condensation of 2-hydrazino-3-methylquinoxaline (1) with various aromatic aldehydes, on treatment with iodobenzene diacetate (IBD) in dichloromethane, undergo oxidative cyclization to exclusively afford 1-aryl-4-methyl-1,2,4-triazolo[4,3-a] quinoxalines(5) in excellent yield.