Metal free synthesis of tetrahydrobenzo[a]xanthenes using orange peel as a natural and low cost efficient heterogeneous catalyst

Abstract

In this work, a facile, efficient and metal free catalytic system has been developed for the synthesis of tetrahydrobenzo[a]xanthene derivatives via a one-pot three-component condensation of various aldehydes, 2-naphthol, and dimedone. For the first time, the orange peel as a green, acidic, and low cost natural catalyst with high porosity and high efficiency was used in tetrahydrobenzo[a]xanthenes synthesis procedure. This environmental-friendly novel catalytic system led to the desired products in high to excellent yields under solvent free conditions at 120 °C.