Silica-bonded n-propyldiethylenetriamine sulfamic acid (SBPDSA) was found as an efficient solid acid for the synthesis of coumarins. Coumarin derivatives were obtained via the Pechmann condensation reaction of phenols and β-keto-esters at 80 oC under solvent-free conditions. Also, biscoumarins were obtained via the condensation of aldehydes and 4-hydroxycoumarin in water at reflux conditions. The heterogeneous solid […]
A mild and efficient method has been developed for the preparation of substituted coumarins from reaction of various phenols with different β-ketoesters via Pechmann condensation in the presence of Brønsted acidic ionic liquid (N-(4-sulfonic acid) butyl triethylammonium hydrogen sulfate) as an effective catalyst under solvent-free conditions. Different phenols reacted with ethyl acetoacetate to produce the […]
Nano sulfated titania was tested as solid acid heterogeneous catalyst for the synthesis of 4-(Trifluoromethyl) coumarin and coumarin derivatives under solvent-free condition. Factorial design evidenced a positive effect of reaction temperature, amount of catalyst, and solvents. This nano-sized sulfated titania has been prepared by a sol-gel hydrothermal process. The prepared sulfated titania showed high catalytic […]
