1-(1-Propylsulfonic)-3-methylimidazolium chloride Brønsted acidic ionic liquid catalyzed one-pot synthesis of 14-aryl-14H-dibenzo[a,j]xanthene derivatives under solvent-free conditions

A rapid, green and efficient method for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthene derivatives through a one-pot condensation of 2-naphthol with various aromatic aldehydes in the presences of several acidic ionic liquids including [PSMIM]Cl, [BMIM]HSO4, [BMIM]Cl, [BMIM]Br, and [BMIM]BF4 as organocatalysts and task-specific acidic ionic liquids (AILs) under solvent-free conditions is described. Compared with other synthetic methods, this new method has the advantages such as milder reaction conditions, good to excellent yields, short reaction times, and environmentally benign procedure. Also, 1-(1-Propylsulfonic)-3-methylimidazolium chloride [PSMIM]Cl acts as a catalyst under solvent-free conditions and can be recovered and reused six times without apparent loss of its catalytic activity.