Au catalyzed synthesis of benzimidazoles from 2-nitroanilines and CO2/H2

Hao, Leiduan; Zhao, Yanfei; Yu, Bo; Zhang, Hongye; Xu, Huanjun; Liu, Zhimin

doi:10.1039/c4gc00153b

Cited by 68 publications

(36 citation statements)

References 25 publications

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“…Recently, Liu et al. reported the synthesis of benzimidazoles from 2‐nitroanilines and CO 2 /H 2 using a supported Au catalyst . The superior performance of Au catalysts for CO 2 activation led us to investigate the possibilities offered by Au catalysts for the methylation of amines with CO 2 and H 2 .…”

Section: Introductionmentioning

confidence: 99%

Direct Methylation of Amines with Carbon Dioxide and Molecular Hydrogen using Supported Gold Catalysts

Tang

Bao

et al. 2015

ChemSusChem

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The N-methylation of amines with CO2 and H2 is an important step in the synthesis of bioactive compounds and chemical intermediates. The first heterogeneous Au catalyst is reported for this methylation reaction with good to excellent yields. The average turnover frequency (TOF) based on surface Au atoms is 45 h(-1) , which is the highest TOF value ever reported for the methylation of aniline with CO2 and H2 . Furthermore, the catalyst is tolerant toward a variety of amines, which includes aromatic, aliphatic, secondary, and primary amines. Preliminary mechanistic studies suggest that the N-alkyl formamide might be an intermediate in the N-methylation of amine process. Moreover, through a one-pot process, it is possible to convert primary amines, aldehydes, and CO2 into unsymmetrical tertiary amines with H2 as a reductant in the presence of the Au catalyst.

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Section: Introductionmentioning

confidence: 99%

Direct Methylation of Amines with Carbon Dioxide and Molecular Hydrogen using Supported Gold Catalysts

Tang

Bao

et al. 2015

ChemSusChem

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“…The reaction of 2‐nitroaniline ( 41 ) with CO 2 and H 2 at 100°C gave diamine ( 4 ) that further combined with CO 2 for 12–48 h in N ‐methylpyrrolidone as a solvent to build benzimidazole nucleus. The yield of the product isolated was 90–95% (Scheme ) .…”

Section: Nano‐transition Metal Catalyzed Oxidative Coupling Of O‐phenmentioning

confidence: 99%

Recent Trends in the Synthesis of Benzimidazoles From o‐Phenylenediamine via Nanoparticles and Green Strategies Using Transition Metal Catalysts

Singhal

Khanna

Panda

et al. 2019

Journal of Heterocyclic Chem

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Benzimidazole is a heterocyclic moiety of immense importance as it acts as a primary “biolinker” in diverse synthetic routes to obtain bioactive compounds. Substituted benzimidazoles are known to possess a varied range of pharmacological applications, namely, anti‐cancer, anti‐diabetic, anti‐inflammatory, and antiviral like anti‐HIV and anti‐fungal. A number of reviews covering the important aspects of benzimidazoles such as pharmacological activities, SAR studies, and well‐known methods of synthesis have appeared in the literature. However, green synthetic methods particularly using transition metal (TM) catalysts and their nanoparticles, although being more viable and extensively applied by researchers in the present scenario, have not been exclusively and expansively reviewed. Besides this, the vital precursors required for knitting the skeleton of benzimidazole are mainly o‐aryldiamines. The conventional synthesis generally involved the condensation of these diamines with carbonyl/carboxylic acid derivatives either via high temperature heating or via adding strong acids, mostly resulting in poor yields or mixtures. However, recent trends are replacing these conditions by mild and green conditions through TM catalysts. Therefore, the current review emphasizes on the recent trends adopted in the synthesis of benzimidazoles using condensation reaction of o‐phenylenediamines and various aldehydes/ester/amide/alcohols with TM in a catalytic role in nanoform and under environmentally benign green conditions.

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“…A literature survey reveals that synthesis of benzimidazole derivatives can be accomplished by using SiO 2 -OPO 3 H [24], tosic acid on silica gel [25], ZrOCl 2 ÁH 2 O [26], microwaves [27], Cu nanoparticles [28], Cu(OTf) 3 [29], and Au catalyst [30]. Considering the remarkable pharmaceutical significance of these diversified structural entities, there emerges a need to develop greener methodologies for their efficient synthesis.…”

Section: Introductionmentioning

confidence: 99%

Novel dibenzo-18-crown-6 ether functionalized bis-benzimidazole derivatives: synthesis and antifungal evaluation

et al. 2015

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A series of novel 18-crown-6 ether functionalized bis-benzimidazole derivatives (3a-g) have been synthesized by reacting various substituted ortho-phenylene diamines and pyridine diamines with 4,4 0 -diformyl dibenzo-18-crown-6 ether (1). The required starting material 4,4 0 -diformyl dibenzo-18-crown-6 ether (1) was prepared by Duff formylation method. All synthesized novel molecules have been identified on the basis of infrared (IR), 1 H nuclear magnetic resonance (NMR), 13 C NMR, mass spectroscopy (MS), and elemental analyses. The title compounds (3a-g) were tested for antifungal activity against Aspergillus niger, Trichothecium sp., Rhizopus sp., and Sclerotium rolfsii fungi species using agar well diffusion method, showing mild to good results.Electronic supplementary material The online version of this article (

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Au catalyzed synthesis of benzimidazoles from 2-nitroanilines and CO2/H2

Cited by 68 publications

References 25 publications

Direct Methylation of Amines with Carbon Dioxide and Molecular Hydrogen using Supported Gold Catalysts

Direct Methylation of Amines with Carbon Dioxide and Molecular Hydrogen using Supported Gold Catalysts

Recent Trends in the Synthesis of Benzimidazoles From o‐Phenylenediamine via Nanoparticles and Green Strategies Using Transition Metal Catalysts

Novel dibenzo-18-crown-6 ether functionalized bis-benzimidazole derivatives: synthesis and antifungal evaluation

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