a simple highly versatile and efficient sonochemical synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles is achieved by condensation of 1,2-dicarbonyl compound, aldehyde, ammonium acetate and primary amine using antimony trichloride immobilized on silica gel (sio2-osbcl2) as a catalyst in ethanol at moderate temperature. operational simplicity, practicability and applicabi...

a mild and green method has been developed for the preparation of coumarins derivatives through the one-pot reactions. in our study,various phenols and ethyl acetoacetate compound in which we used silica-supported boron sulfonic acid [sio2/b(so4h)3] as a new, highly efficient and tri-functional inorganic brønsted acid catalyst were processed under solvent-free condition and thermal. the catalys...

In general, Lewis acid catalysts are metal-based compounds that owe their reactivity to a low-lying empty orbital. However, one potential Lewis acid that has received negligible attention as a catalyst is the carbocation. We have demonstrated the potential of the carbocation as a highly powerful Lewis acid catalyst for organic reactions. The stable and easily available triphenylmethyl (trityl) ...

Silica boron sulfonic acid [SiO2–B(OSO3H)3] as an inexpensive, reusable, and Lewis and Brønsted acid catalyst was successfully synthesized, and used for the one-pot three-components synthesis of biologically active substituted Hantzsch 1,4-dihydropyridine derivatives  in the absence of solvent at 90ºC. Silica boron sulfonic acid is attractive and efficient, because it plays in two role as a Lew...

Convenient procedure for the synthesis of corresponding pyrano[2,3-d]pyrimidine derivatives were developed via one-pot three-component reaction of aryl aldehyde derivatives, malononitrile with barbituric acids in the presence of copper (II) chloride dihydrate (CuCl2.2H2O) as highly efficient Lewis acid catalyst. This protocol has advantages such as readily and inexpensive catalyst, high reactio...

TiCl4/nano-cellulose as a biodegradable and eco-friendly Lewis acid catalyst was synthesized via reaction of nano-cellulose and TiCl4. This catalyst was characterized and used for synthesis of asymmetric highly functionalized tetrahydropyridines via a five-component condensation reaction of p-substituted anilines, aldehydes and ethyl acetoacetate under solvent-free condition. Simple methodology...

While Lewis acids andmetal amides are among themost frequently usedmetal species, they are believed to be incompatible when combined. Here we describe a Lewis acid/metal amide hybrid, which contains electron-withdrawing groups and basic and bulky nitrogen functional groups in the same metal complex, as a novel catalyst. We have synthesized In(N(SiMe3)2)2Cl (In(HMDS)2Cl) and In(HMDS)2OTf as Lewi...