Fluoroboric Acid Adsorbed on Silica-Gel–Catalyzed Synthesis of 14-Aryl-14H-dibenzo[a,j]xanthene Derivatives

Abstract

A simple and efficient procedure has been developed for the preparation of 14-aryl-14H-dibenzo[a,j]xanthene derivatives using fluoroboric acid adsorbed on silica gel as a heterogeneous catalyst. The methodology involves the one-pot condensation reaction of β-naphthol and aryl aldehydes under solvent-free conventional heating conditions. The present approach offers several advantages such as shorter reaction times, simple work-up, excellent yields, low cost, and mild reaction conditions. The catalyst is easily recoverable and reusable without loss of its catalytic activity.

Keywords:

• Aldehyde
• HBF₄-SiO₂
• heterogeneous catalyst
• β-naphthol
• solvent-free conditions
• xanthene

ACKNOWLEDGMENTS

We are grateful for financial support from Hebei Normal University (L20061314), the Nature Science Foundation of Hebei Province (B2008000149), and the Natural Science Foundation of Hebei Education Department (2006318).

Notes

^a Isolated yield.

^b 5 mL toluene were added.

^c 5 mL ClCH₂CH₂Cl were added.

^d 5 mL EtOH were used.

^a Isolated yield.