Highly Efficient Synthesis of 14-Aryl-14H-dibenzo[a,j]xanthenes Catalyzed by Carbon-Based Solid Acid Under Solvent-Free Conditions

Abstract

Carbon-based solid acid, a strong solid acid catalyst, was prepared readily by sulfonation and carbonization of aromatic compounds such as naphthalene in sulfuric acid at 250°C. This reusable and ecofriendly carbon-based solid acid highly efficiently condensed β-naphtol with aromatic aldehydes under solvent-free conditions, and the corresponding aryl-14-H-dibenzo[a,j]xanthenes were obtained in excellent yields. The catalyst can be reused several times without loss of its activity.

Keywords:

• Naphthol
• solid acid catalyst
• solvent-free
• sulfonated carbon
• xanthene

ACKNOWLEDGMENT

The financial support of this work by the Center of Excellence of Chemistry of University of Isfahan is acknowledged.

Notes

^a Reaction conditions: 4-chlorobenzaldehyde (1 mmol), β-naphthol (2 mmol), catalyst (20 mg), reflux.

^b Isolated yields.

^a Reaction conditions: 4-chlorobenzaldehyde (1 mmol), β-naphthol (2 mmol), catalyst (20 mg), 30 min.

^b Isolated yield.

^a Isolated yields.

^b Reaction temperature 125°C.

^a Reaction conditions: 4-chlorobenzaldehyde (1 mmol), β-naphtol (2 mmol), catalyst (20 mg), 30 min.

^b Isolated yield.