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.
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.