An efficient and reusable nano catalyst for the synthesis of benzoxanthene and chromene derivatives.

Potassium fluoride impregnated on clinoptilolite nanoparticles (KF/CP NPs) was investigated as an efficient solid base catalyst for multicomponent condensation reaction. A broad range of aromatic aldehydes and enolizable compounds were condensed with 2-naphthol or 4-hydroxycumarine. The reaction was carried out under a solvent-free condition to give the corresponding benzoxanthene and pyrano [3,2-c]chromene derivatives in high yields. The low cost and availability of catalyst, novel and green procedure makes this strategy more useful for the preparation of tetrahydrobenzo[a]-xanthene-11-one and pyrano [3,2-c]chromene derivatives.