Nano ZnO Catalyzed One-Pot Synthesis of Benzimidazoles from o-Phenylenediamine with Aldehydes
作者:Kun Qian、Xin Nian、Guan-Ming Zhu、Dong Mei Cui、Chen Zhang
DOI:10.14233/ajchem.2015.19076
日期:——
Nano-ZnO was found to be a highly efficient and reusable heterogeneous catalyst for the one-pot synthesis of substituted benzimidazoles from aromatic aldehydes with o-phenylenediamine in moderate to good yield. The spent catalyst can be easily recovered and reused for five cycles with consistent activity.
Chemoselective reduction of nitroaromatics using recyclable alumina-supported nickel nanoparticles in aqueous medium—exploration to one pot synthesis of benzimidazoles
作者:Avishek Ghatak、Sanjay Bhar
DOI:10.1080/00397911.2021.2024853
日期:2022.2.1
protocol for chemoselective and regioselective reduction of nitroaromatics in water has been achieved using easily accessible alumina-supported nickel nanoparticles as a stable recyclable heterogeneous catalyst. Various sensitive substituents like allyloxy, benzyloxy, t-butyldimethylsilyloxy, hydroxymethyl, alkoxycarbonyl, formyl, keto, carboxylic acid, chloro, bromo, azo and cyano were tolerated in
Selectivity control during the solid supported protic acids catalysed synthesis of 1,2-disubstituted benzimidazoles and mechanistic insight to rationalize selectivity
作者:Dinesh Kumar、Damodara N. Kommi、Rajesh Chebolu、Sanjeev K. Garg、Raj Kumar、Asit K. Chakraborti
DOI:10.1039/c2ra21994h
日期:——
Selectivity control during the formation of 1,2-disubstituted benzimidazoles has been achieved for the reaction of o-phenylenediamine with aldehydes in the presence of solid supported protic acids as catalysts and choosing an appropriate reaction medium. Perchloric acid adsorbed on silica-gel (HClO4–SiO2) was found to be the most effective catalyst system for the synthesis of 1,2-disubstituted benzimidazoles in EtOH at rt. Apart from the catalyst and solvent, the electronic and steric factors of the aldehyde and the electronic factor of the o-phenylenediamine are also significant contributory factors in dictating the selectivity. An understanding of the mechanistic course of the formation of the 1,2-disubstituted benzimidazoles has been outlined that would rationalise the origin of selectivity control under the set experimental parameters.
2-Substituted and 1,2-disubstited benzimidazoles were prepared efficiently from o -phenylenediamines and aryl aldehydes using p -toluenesulphonic acid (5 mol%)-on-silica gel as a cheap and environmentally benign catalyst.
Nano indium oxide: an efficient catalyst for the synthesis of 1,2-disubstituted benzimidazoles in aqueous media
作者:Sougata Santra、Adinath Majee、Alakananda Hajra
DOI:10.1016/j.tetlet.2012.02.021
日期:2012.4
Synthesis of 1,2-disubstitutedbenzimidazoles has been developed by the condensation of diamine with aldehydes using nano In2O3 as an efficient catalyst under mild reaction conditions in aqueous media. The procedure is applicable to aryl, aliphatic, heteroaryl aldehydes. In2O3 nanoparticles are recyclable without the loss of significant catalytic activity.
通过在水介质中温和的反应条件下,使用纳米In 2 O 3作为有效的催化剂,通过二胺与醛的缩合反应,开发了1,2-二取代的苯并咪唑的合成方法。该方法适用于芳基,脂族,杂芳基醛。In 2 O 3中的纳米颗粒是可回收的,而不会损失明显的催化活性。