An efficient synthesis of 14-substituted-14H-dibenzo[a,j]xanthene derivatives promoted by a nano isopolyoxomolybdate under thermal and solvent-free conditions

Synthesis of 14-substituted-14H-dibenzo[a,j]xanthene derivatives using the condensation of β-naphthol with wide range of various aldehydes in the presence of a Keplerate type giant nanoporous isopolyoxomolybdate, (NH4)42[MoVI72MoV60O372(CH3COO)30(H2O)72], represented as {Mo132}, as an efficient catalyst under solvent free condition is reported. The catalyst was prepared according to a previously published literature procedure using inexpensive and readily available starting materials. Furthermore, the catalyst could be recovered conveniently and reused efficiently such that a considerable catalytic activity still could be achieved after fifth run. Other beneficial features of this new synthetic approach include short reaction times, high yields, clean reaction profiles, and a simple work‐up procedure.