A highly efficient magnetic solid acid catalyst for synthesis of 2,4,5-trisubstituted imidazoles under ultrasound irradiation
作者:Javad Safari、Zohre Zarnegar
DOI:10.1016/j.ultsonch.2012.10.004
日期:2013.3
Fe3O4 nanoparticles were prepared by chemical coprecipitation method and subsequently coated with 3-aminopropyltriethoxysilane (APTES) via silanization reaction. Grafting of chlorosulfuric acid on the amino-functionalized Fe3O4 nanoparticles afforded sulfamic acid-functionalized magnetic nanoparticles (SA-MNPs). SA-MNPs was found to be a mild and effective solid acid catalyst for the efficient, one-pot, three-component synthesis of 2,4,5-trisubstituted imidazoles under ultrasound irradiation. This protocol afforded corresponding imidazoles in shorter reaction durations, and in high yields. This green procedure has many obvious advantages compared to those reported in the previous literatures, including avoiding the use of harmful catalysts, easy and quick isolation of the products, excellent yields, short routine, and simplicity of the methodology. (C) 2012 Elsevier B.V. All rights reserved.
Zinc (II) [tetra(4-methylphenyl)] Porphyrin: a Novel and Reusable Catalyst for Efficient Synthesis of 2,4,5-trisubstituted Imidazoles Under Ultrasound Irradiation
An efficient three-component one-step synthesis of 2,4,5-trisubstituted imidazoles by condensation reaction of 1,2-diketones or α-hydroxyketones with aromatic aldehydes and ammonium acetate using Zinc (II) (tetra (4-methylphenyl)) porphyrin as a novel and reusable catalyst under ultrasound irradiation at ambient temperature is described. In this method, α-hydroxyketones as well as 1,2-diketones were