Mild preparation of 2-amino-3-cyano-4-aryl-4H-benzo[h]chromenes and 2-amino-3-cyano-1-aryl-1H-benzo[f]chromenes, under solvent-free conditions, catalyzed by recyclable basic ionic liquids

摘要

The mild basic ionic liquids 2-hydroxyethanaminium formate, 3-hydroxypropanaminium formate, 2-hydroxyethanaminium acetate, and 3-hydroxypropanaminium acetate catalyze three-component condensation of aromatic aldehydes, malononitrile, and alpha or beta-naphthol to afford the corresponding 2-amino-3-cyano-4-aryl-4H-benzo[h]chromenes and 2-amino-3-cyano-1-aryl-1H-benzo[f]chromenes, respectively. Attractive features of the method are the simple procedure, high yields, short reaction time, and environmentally benign method. The inexpensive and non-toxic ionic liquids can be reused several times without noticeable loss of their activity. These ionic liquids are better catalysts than others reported in the literature.