eshagh rezaee nezhad

The Fe3O4 nanoparticles and the supported ionic liquid (Fe3O4-IL) were produced and used as efficient magnetic catalysts to synthesize the benzimidazole derivatives under solvent and solvent-free conditions. Quantitative conversion of the reactants was achieved under solvent-free conditions; catalyst reusability, through convenient magnetic decantation, showing an insignificant loss in activity. The catalyst can be readily isolated by using an external magnet and no obvious loss of activity was observed when the catalyst was reused in seven consecutive runs.

A simple and facile method for the preparation ofFe2+ supported on hydroxyapatite-core-shell-γ-Fe2O3 nanoparticles (γ-Fe2O3@HAp-Fe2+ NPs) as an environmentally friendly and recyclable green catalyst is described and used for the one-pot synthesis of benzimidazoles and benzoxazole derivatives via reactions between aromatic aldehydes and ortho‐phenylenediamine or ortho‐aminophenol in aqueous media conditions at room temperature. This green method offers significant advantages in terms of its simplicity, very low loading of catalyst, high catalytic efficiency, good to excellent product yields, short reaction time, simple experimental and work-up procedure. Also, after the reaction, γ-Fe2O3@HAp-Fe2+ NPs can be easily recovered and reused for at least ten runs. This magnetic nanoparticle was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM) and vibrating sample magnetometry (VSM) spectra.

An efficient and simple method for the preparation of Si-Imidazole-HSO4 functionalized magnetic Fe3O4 nanoparticles (Si-Im-HSO4 MNPs) and used as an efficient and reusable magnetic catalysts for the regioselective ring opening of epoxides under green conditions in water. This catalyst was used for the ring opening of epoxide corresponding to the thiocyanohydrins and azidohydrines. Compared to the classical ring opening of epoxides, this new method consistently has the advantage of excellent yields, short reaction times, and methodological simplicity.

Fe2+supported on hydroxyapatite- core-shell magnetic γ-Fe2O3 nanoparticles (γ-Fe2O3@HAp-Fe2+ NPs) is reported as a novel, efficient, reusable and heterogeneous catalyst. In this protocol, we used this catalyst for the synthesis of 4-dihydropyrimidin-2(1H)-ones/thiones in good to high yields by the reaction of aromatic aldehyde, β-dicarbonyl and urea/thiourea under solvent free condition.The catalyst can be readily isolated by using an external magnet and no obvious loss of activity was observed when the catalyst was reused in seven consecutive runs. The mean size and the surface morphology of the nanoparticles were characterized by TEM, SEM, VSM, XRD and FTIR techniques.

Ni2+ supported on hydroxyapatite-core@shell γ-Fe2O3 nanoparticles (γ-Fe2O3@HAp-Ni2+) was found to be a useful catalyst for the synthesis of benzimidazole derivatives from o-phenylenediamine and aldehydes under solvent and solvent-free conditions at 80 °C. This reaction affords the corresponding benzimidazole derivatives compared with the classical reactions this method consistently gives a high yield, easy magnetic separation, a short reaction time, simple workup and recyclable property of the catalyst. In this way, the catalyst was readily recovered using an external magnet and could be reused in five consecutive runs without significant loss of reactivity. The mean size and the surface morphology of the nanocatalyst were characterized by TEM, SEM, VSM, XRD and FTIR techniques.

In this research, we have developed cheap recyclable and task-specific acidic ionic liquids (AILs) 1-hydrogen-3-methylimidazolium hydrogen sulfate [Hmim]HSO4, 1-hydrogen-3-methylimidazolium chloride [Hmim]Cl, 2-pyrrolidonium hydrogensulfate [Hnhp]HSO4 and applied them in acid catalyzed synthesis of quinoxaline derivatives from 1,2-phenylendiamines and 1,2-dicarbonyl compounds. The products could be separated from the catalyst simply by filtration and the catalyst could be recycled and reused several times without noticeable loss of efficiency.