Potassium dodecatungstocobaltate trihydrate (K5CoW12O40 · 3H2O): A mild and efficient reusable catalyst for the synthesis of aryl-14H-dibenzo[a.j]xanthenes under conventional heating and microwave irradiation

A simple and efficient procedure has been developed for the preparation of aryl-14H-dibenzo[a.j]xanthenes by a one-pot condensation of β-naphthol and aryl aldehydes, in the presence of potassium dodecatungstocobaltate trihydrate [K5CoW12O40 · 3H2O, (0.01 mol%)] as a heterogeneous catalyst in a solvent-free media using both conventional heating and microwave irradiation. The present methodology offers several advantages such as excellent yields, simple procedure, short reaction times (1.5–2.0 h and 2.0–3.0 min) and milder conditions and the catalyst exhibited remarkable reusable activity.