Synthesis 12-Aryl or 12-Alkyl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-one derivatives catalyzed by dodecatungstophosphoric acid

An efficient protocol for the synthesis of 12-aryl or 12-alkyl-8,9,10,12-tetrahydro-benzo[a]xanthen-11-one derivatives has been developed via three-component reaction of aldehyde, 2-naphthol and 1,3-cyclohexadione or 5,5-dimethyl-1,3-cyclohexadione in the presence of 12-tungstophosphoric acid (H3PW12O40) under solvent-free conditions. The present methodology offers several advantages such as high yields, simple procedure, low cost, short reaction times, and mild conditions.