Polystyrene-supported 1-methylimidazolium tetrachloro ferrate: Synthesis, characterization, and application as an efficient and reusable heterogeneous catalyst for one-pot synthesis of 4h-chromene derivatives in aqueous media

Polystyrene-supported 1-methylimidazolium tetrachloroferrate (PS[mim][FeCl4]) was prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The catalytic activity of the heterogeneous catalyst was evaluated through one-pot synthesis of 2-amino-4H-chromene-3-carbonitriles via the three-component condensation reaction of aromatic aldehydes, malononitrile and dimedone or 2-naphthol in water. The heterogeneous catalyst could be recovered easily and reused five times without significant loss of its catalytic activity.               KEY WORDS: Green chemistry, Heterogeneous catalyst, 4H-chromene derivatives, Multi-component reactions, One-pot synthesis Bull. Chem. Soc. Ethiop. 2018, 32(3), 531-540.DOI: https://dx.doi.org/10.4314/bcse.v32i3.1

[Fe3O4@SiO2@(C3H6)2-(Imidazolium)2-Butyl][MnCl42-] as a novel nanomagnetic catalyst for the one-pot synthesis of tetrahydrobenzo[b]pyran derivatives

In this article a convenient method for the synthesis of tetrahydrobenzo[b]pyran derivatives using imidazolium-based ionic liquid-stabilized on magnetic nanoparticles [Fe3O4@SiO2@(C3H6)2-(Imidazolium)2-Butyl][MnCl42-] as a new heterogeneous catalyst has been described. These compounds were synthesized via one-pot three component condensation reaction between several aromatic aldehydes, malononitrile, and dimedone in water under reflux condition. The magnetic nanoparticle catalyst was fully characterized by Fourier transform infrared, scanning electron microscopy, energy dispersive X-ray spectroscopy, and vibrating sample magnetometer. Furthermore, the solid catalyst could be recovered and reused conveniently several times with satisfactory yields.               KEY WORDS: Chromene derivatives, Magnetic nanoparticles, Dicationic ionic liquid, Reusability, One-pot synthesis Bull. Chem. Soc. Ethiop. 2018, 32(2), 309-321. DOI: https://dx.doi.org/10.4314/bcse.v32i2.1