pTSA-catalyzed one-pot synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones in ionic liquid and neat conditions

Multi-component condensation of β-naphthol, aromatic aldehydes, and cyclic 1,3-dicarbonyl compounds catalyzed by p-toluenesulfonic acid has been accomplished for the synthesis of a series of 12-aryl-8,9,10,12-tetrahydrobenzoa]xanthen-11-ones in ionic liquid(bmim]BF₄) and in solvent-free media. High yields, ease of recovery, and reusable reaction medium (ionic liquid) with consistent activity makes this protocol efficient and environmentally benign.