Fe 3 O 4 @chitosan nanoparticles: a valuable heterogeneous nanocatalyst for the synthesis of 2,4,5-trisubstituted imidazoles (original) (raw)
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Asian Journal of Green Chemistry, 2019
Fe3O4 magnetic nanoparticles (Fe3O4 MNPs) were prepared and used as an eco-friendly, reusable, low-cost and efficient catalyst for the synthesis of 2,4,5-trisubstituted imidazoles via three-component reaction of aromatic aldehydes with benzil and ammonium acetate under low power microwave irradiation and solvent-free condition. This one-pot procedure was very simple with good to excellent yields. Easy separation of Fe3O4 MNPs from the reaction mixture by an external magnet and the reusability of the catalyst were the considerable points of the reaction.
Turk J Chem
Multicomponent, one-pot, highly efficient, and environmentally adapted synthesis of some novel polysubstituted imidazoles by the use of various aldehydes, benzil, aliphatic, and aromatic primary amines and ammonium acetate in the presence of Fe 3 O 4 nanoparticles as catalyst under solvent-free condition is explained. A highly efficient role of Fe 3 O 4 nanoparticles as catalyst in this synthesis was shown. By this advantage, several polysubstituted imidazoles as pharmaceutical important molecules can be prepared in high yield and high purity. This method is very easy and rapid for the synthesis of imidazole derivatives.
Journal of Chemical Sciences, 2014
A simple one-pot synthesis has been developed for the synthesis of 2,4,5-trisubstituted imidazoles using magnetic recyclable spinel nano copper and cobalt ferrites by the condensation of benzil, aromatic aldehyde and ammonium acetate in ethanol as solvent. The reaction, with these catalysts was carried out under mild reaction conditions with very good yields of substituted imidazoles. These catalysts can be recycled very easily and reused, which makes this methodology environmentally benign.
Research on Chemical Intermediates, 2018
Cross-linked poly(4-vinylpyridine) supported Fe 3 O 4 nanoparticles, abbreviated as [P 4-VP]-Fe 3 O 4 NPs, were easily prepared as a new magnetic polymeric catalyst and efficiently used for the synthesis of imidazole derivatives. The polymeric catalyst was characterized by using of various techniques including field emission scanning electron microscopy, X-ray diffraction, vibrating sample magnetometry and Fourier transform infrared spectroscopy (FT-IR) techniques. According to the obtained results, good dispersion of Fe 3 O 4 nanoparticles on the polymer-support and excellent magnetic property of the catalyst were achieved. Various methods have been reported for the synthesis of multi-substituted imidazoles by the reaction of benzil, aldehydes and amines or ammonium acetate in the presence of various catalysts. These methods have some disadvantages including long reaction times, nonreusability of the catalyst, polluted reaction conditions, effluent pollution, and low yields; therefore, we wish to report an efficient, fast, clean and green method for the synthesis of imidazole derivatives that has been developed by one-pot condensation reaction of benzil, ammonium acetate and aldehydes in the presence of [P 4-VP]-Fe 3 O 4 nanoparticles. The catalyst displayed good catalytic activity when applied for the synthesis of imidazole derivatives. Various imidazole derivatives were prepared in high to excellent yields (68-99%) with short reaction time and high purity. The present procedure offers advantages such as short reaction time, simple reaction work-up, and the polymeric catalyst can be regenerated and reused several times without significant loss of its activity.
Frontiers in Chemistry, 2020
In this protocol, Fucoidan (FU), a fucose-rich sulfated polysaccharide extracted from brown algae Fucus vesiculosus was used for in situ preparation of magnetic Fe3O4@FU. Nanoco magnetic properties of Fe3O4@FU were investigated by energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) adsorption method, and vibrating sample magnetometer (VSM). The catalytic activity of Fe3O4@FU was employed for the synthesis of tri- and tetra-substituted imidazoles through three- and four-component reactions respectively, between benzyl, aldehydes, NH4OAc and benzyl, aldehydes, NH4OAc, and amine under reflux in ethanol. It is worth nothing that excellent yields, short reaction times, chromatography-free purification, and environmental friendliness are highlighted features of this protocol.
Research on Chemical Intermediates, 2018
A one-pot, multi-component, synthetic method for preparation of 2-amino-4substituted-1,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitriles has been developed. It was accomplished by mixing 2-aminobenzimidazole, aldehyde and malononitrile in the presence of S-Chit-HAp@Fe 3 O 4 as a nanocatalyst in aqueous medium. The catalyst (S-Chit-HAp@Fe 3 O 4) was synthesized using a co-precipitation method and further characterized by using FT-IR, XRD, FE-SEM, EDX, HR-TEM, TGA and VSM analysis. It was found that the catalyst exhibits magnetic properties and showed high catalytical activity for the synthesis of 2-amino-4-substituted-1,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitriles.
Journal of the Chinese Advanced Materials Society, 2015
ABSTRACT Copper nanoparticles (Cu NPs) were found to be an extremely efficient and effective catalyst for synthesis of 2, 4, 5-trisubstituted imidazole via three-component reactions of benzil, aldehydes and ammonium acetate at room temperature. The obtained products were followed by TLC (Thin Layer Chromatography). After completion of the reaction, the reaction mixture was diluted with water (20 mL). The solid imidazole product was washed with water and recrystallized from ethanol to remove nano copper to afford the pure imidazole compounds. The method provides several advantages such as simple operation, short reaction time, clean reaction profile, lower catalyst loading and high yield. The used catalyst in reaction could be recovered conveniently and reused for several times. The high yields of reactions are attributed to the effect of copper nanoparticles due high surface to volume ratio. Due to simple work up procedures, very short times and excellent product yields make this method an interesting alternative to other methodologies.
International Journal of NanoScience and Nanotechnology, 2016
In this work, an efficient and facile method has been developed for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones from a condensation reaction of 2-aminobenzamide with various alkyl,aryl and alicyclic aldehydes or ketones using Fe3O4/chitosan as an environmentally benign, magneticallyrecoverable nanocomposite catalyst in ethanol at room temperature in high to excellent yields undermild reaction conditions. The Fe3O4/chitosan composite nanocatalyst was first prepared by a sol-gelmethod and characterized by using a variety of conventional techniques including Fourier transformsinfrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) andX-ray diffraction (XRD) analyses. The present work include several advantages such as avoiding the useof toxic solvents or expensive catalysts, generality, high yields, short reaction times, clean reactionprofile, ease of product isolation, simplicity, recyclability of the catalyst and finally agreement with t...