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...

the silica boron sulfuric acid nanoparticles (sbsans) as an efficient heterogeneous solid acid catalyst with both brønsted and lewis acidic sites catalyzed the preparation of bis-4-hydroxycoumarin derivatives using reaction of aldehydes and 4-hydroxycoumarin under mild and solvent-free condition at room temperature. this new and efficient methodology has advantages in comparison with currently ...

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...

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...

α-Amino nitriles are synthesized in a one-pot, three-component coupling of aldehydes (or ketones), aniline, and trimethylsilyl cyanide using a catalytic amount of choline chloride.2ZnCl2 as a bio Lewis acidic ionic liquid. Mild Lewis acidic characteristic of this ionic liquid allows efficient synthesis of α-amino nitriles from acid sensitive aldehydes.

α-Amino nitriles are synthesized in a one-pot, three-component coupling of aldehydes (or ketones), aniline, and trimethylsilyl cyanide using a catalytic amount of choline chloride.2ZnCl2 as a bio Lewis acidic ionic liquid. Mild Lewis acidic characteristic of this ionic liquid allows efficient synthesis of α-amino nitriles from acid sensitive aldehydes.

α-amino nitriles are synthesized in a one-pot, three-component coupling of aldehydes (or ketones), aniline, and trimethylsilyl cyanide using a catalytic amount of choline chloride.2zncl2 as a bio lewis acidic ionic liquid. mild lewis acidic characteristic of this ionic liquid allows efficient synthesis of α-amino nitriles from acid sensitive aldehydes.

Aromatic carbonyl compounds such as 10-methylacridone form the Lewis acid complexes including paramagnetic and redox active Lewis acids. The fluorescence energies of the Lewis acid complexes are well correlated with the O2*--Lewis acid complexes derived from the gzz-values of the ESR spectra of the superoxide anion-Lewis acid complexes, thus providing a quantitative measure of the Lewis acidity.

β-Cyclodextrin sulfuric acid as a green Lewis acid catalyst has been applied for the preparation of bis(indolyl)methanes, tris(indolyl)methanes and 3,3'-diindolyloxindole derivatives by the condensation of indoles with various carbonyl compounds in aqueous media with high to excellent yields.