ONE-POT SYNTHESIS OF 2,4,5-TRISUBSTITUTED IMIDAZOLES USING [BPy]H2PO4, AN EFFICIENT AND RECYCLABLE CATALYST

An efficient and eco-compatible multicomponent synthesis of 2,4,5-trisubstituted imidazole derivatives using modified-silica-coated cobalt ferrite nanoparticles with tungstic acid

The aim of this study has been to offer a method for the synthesis of 2,4,5-trisubstituted imidazole derivatives based on green chemistry principles. Therefore, a one-pot multicomponent cyclocondensation reaction through aldehyde interaction with ammonium acetate and 1,2-diketone under solvent-free conditions was utilized as an eco-effective synthetic route using CoFe₂O₄@SiO₂@(-CH₂)₃OWO₃H NPs as the catalyst. The stabilized tungstic acid on 3-chloropropyl-anchored SiO₂-coated CoFe₂O₄ magnetic nanoparticles was designed, prepared, and applied as a recyclable heterogeneous acid catalyst to attain high product yield in a short reaction time. The nanocatalyst structure was confirmed using FT-IR, Raman, XRD, FE-SEM, EDX, VSM, and TGA techniques, and the organic product structures were examined by melting point, FT-IR and ¹H NMR analyses.

Controllable access to multi-substituted imidazoles via palladium(ii)-catalyzed C–C coupling and C–N condensation cascade reactions

A novel and efficient protocol for the controllable synthesis of various di-, tri- and tetra-substituted imidazoles via cascade palladium catalyzed C–C coupling followed by intramolecular C–N bond formation was developed.

Ionophore silica-coated magnetite nanoparticles as a recyclable heterogeneous catalyst for one-pot green synthesis of 2,4,5-trisubstituted imidazoles

Novel multi-SO3H functionalized strong Brønsted acidic ionic liquid coated magnetite nanoparticles have been prepared and applied as catalyst for the synthesis of 2,4,5-trisubstituted imidazoles. The results showed that a novel catalyst was very efficient for the reaction and could be magnetically separated and reused at least 6 times with less reduction in its catalytic activity. Operational simplicity, low cost of the catalyst used, high yields, environmental friendliness, wide applicability, reusability and easy recovery of the catalyst using an external magnet are the most important features of this methodology. The catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), X-Ray diffraction analysis (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX), dynamic laser scattering (DLS) and vibrating sample magnetometry (VSM).