Nanocrystalline SiO2–HClO4, as a newly reported catalyst, has been used as an efficient and reusable catalyst for the synthesis of pyrimidine derivatives. The procedure can be successfully applied to the efficient synthesis of mono substituted pyrimidine derivatives, using triethyl orthoformate, ammonium acetate, methyl ketone derivatives. In practice, this method is a combination of a satisfac...

Heterogeneous acid and base catalysts play a crucial role in many important chemical processes. Hard Lewis Brønsted like silica-alumina zeolites have been widely applied numerous reactions; however, developing reusable active soft remain challenge. Herein, we demonstrate for the first time that highly dispersed supported platinum catalyst can act as heterogeneous acid. High turnover numbers reu...

cellulose sulfuric acid was used as an efficient biopolymer-based catalyst for the synthesis of tetrahydropyrimido[4,5-b]quinoline-2,4,6-triones and hexahydro-2h-pyrazolo[5,4-b]quinoline-6-ones via three component reaction of aldehyde, 5,5-dimethyl-1,3-cyclohexadione and 6-amino-1,3-dimethyluracil or 5-amino-3-methyl-1-phenypyrazole under solvent-free conditions at 90 oc. the major advantages o...

TiO2 nanoparticles/melamine Tri sulfonic acid (MTSA) supported on silica gel as an efficient catalytic system for simple, one pot, solvent-free and environmentally benign process for synthesis of dihydropyrimidines via Biginelli reaction at 110 °C is described. It was found that the catalyst is reusable and exhibited remarkable activity. The catalyst can be easily separated and reused several t...

An L-proline based supramolecular hydrogel is used as an efficient heterogeneous organocatalyst for the direct aldol reaction with high stereoselectivity (up to 90% ee) and recyclability (up to 3 runs). The reversible nature of this self-assembled supramolecular system allows for easy recovery and regeneration of the catalyst.

Aerobic oxidation of alcohols in the liquid phase proceeded smoothly in the presence of nanoporous gold catalyst. The catalyst is reusable multiple times without leaching and loss of the catalytic activity. The reaction was applied successfully to a flow system. Adsorptions of O(2) and 1-phenylethanol into the AuNPore were confirmed by TDS analysis.

Dowex-50W-hyodrgen ion exchange resin was used as a reusable catalyst for the synthesis of oxazoline, imidazoline and thiazoline derivatives through condensation reaction between arylnitriles and 2-aminoalcohol, ethylenediamine or 2-aminoethanthiol. This process provides several advantages such as excellent yields of the products, simple operation, convenient separation and inexpensive and recy...

2-Methylpyridinium trifluoromethanesulfonate ([2-MPyH]OTf) catalyzed synthesis of 1,5benzodiazepine and quinoxaline derivatives in the reaction of between o-phenylenediamine and ketone (synthesis of 1,5-benzodiazepine derivatives) or 1,2-diketone (synthesis of quinoxaline derivatives) in high yields and short time reaction. The catalyst can be separated from the products by a change in the solv...

In this study, an efficient and green process for the synthesis of dihydropyrimidin-2(1H)-ones from aromatic benzaldehydes, ethyl acetoacetate and urea using Al-MCM-41 as heterogeneous catalyst and microreactor under solvent-free conditions has been developed. The advantages of this method are easy work-up procedure, regeneration of the catalyst, clean and neutral reaction conditions.