Efficient and one-pot synthesis of 1,8-dioxo-octahydroxanthenes was described by Knoevenagel condensation, Michael addition and cyclodehydration of dimedone. This reaction was carried out through condensation of dimedone and various aromatic aldehydes in the presence of task-specific Brønsted acidic ionic liquid under solvent free conditions. The catalyst could be recycled five times without si...

Ammonium monovanadate (NH4VO3) has been devoted as an efficient, commercially available, eco-friendly and reusable catalyst for the synthesis of bis(indolyl)methanes (BIMs), oxindole derivatives and also Michael adducts of indoles at 50 °C under solvent-free conditions. The reusability of this solid acid catalyst in addition with its selectivity has also been examined.

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 s...

Ammonium monovanadate (NH4VO3) has been devoted as an efficient, commercially available, eco-friendly and reusable catalyst for the synthesis of bis(indolyl)methanes (BIMs), oxindole derivatives and also Michael adducts of indoles at 50 °C under solvent-free conditions. The reusability of this solid acid catalyst in addition with its selectivity has also been examined.

An effective one-pot synthesis of dihydropyrimidinonoes in solvent free conditions using CuCl2 as an inexpensive and readily available reagent through Biginelli condensation reaction of aldehyde derivatives, 1,3-dicarbonyl compounds and urea is described. Excellent yields, short reaction times for formation of the products and simple work-up are attractive features of this green protocol.

CuO-CeO2 nanocomposite is reported as a green and highly efficient recyclable catalyst for the multicomponent  synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones under solvent-free conditions. The catalyst was synthesized by co-precipitation method and characterized by XRD, BET specific surface area, FESEM and EDS analysis.

An efficient and mild methodology for rapid and efficient synthesis of isatin Schiff bases was described under microwave irradiation and solvent free condition.aromatic or heterocyclic Primary amines and isatin could be selectively reacted under microwave irradiation into the corresponding isatin Schiff bases in high yields and short reaction time.  

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...

Montmorillonite modified is an efficient environmental friendly catalyst under one-pot-three-component synthesis of 3,4-dihydropyrimidine-2(1H) ones. The preparation was performed with an aldehyde, 1,3-dicarbonyl compounds, urea or thiourea under solvent-free conditions. In comparison with the other methods of Biginelli reaction, this new method has short reaction time inexpensive catalyst and ...