Efficient production of 2-amino-4H-chromenes and 14-aryl-14H-dibenzo[a, j]xanthenes catalyzed by N, N-diethyl-N-sulfoethanaminium hydrogen sulfate

In this study, acidic ionic liquid N, N-diethyl-N-sulfoethanaminium hydrogen sulfate {[Et3N-SO3H]HSO4} was utilized to promote two classes of useful organic transformations under solvent-free conditions including, i) the condensation of arylaldehydes with malononitrile and 1-naphthol, leading to 2-amino-4H-chromenes, and ii) the condensation reaction of arylaldehydes with 2-naphthol to give 14-aryl-14H-dibenzo[a, j]xanthenes. The ionic liquid efficiently catalyzed the reactions, and the products were obtained in excellent yields (94-98%) within short reaction times (8-30 min).