Facile and efficient one-pot synthesis of benzimidazoles using lanthanum chloride.

Yekkirala Venkateswarlu,Panuganti Leelavathi,Sudhagani Ramesh Kumar

doi:10.1186/2191-2858-3-7

Abstract

BackgroundWe report the synthesis of benzimidazoles using lanthanum chloride as an efficient catalyst. One-pot synthesis of 2-substituted benzimidazole derivatives from o-phenylenediamine and a variety of aldehydes were developed under mild reaction conditions.ResultsWe have examined the effect of different solvents using the same reaction conditions. The yield of the product varied with the nature of the solvents, and better conversion and easy isolation of products were found with acetonitrile. In a similar manner, the reaction with o-phenylenediamine and 3,4,5-trimethoxybenzaldehyde was carried out without any solvents. The observation shows that the reaction was not brought into completion, even after starting for a period of 9 h, and the reaction mixture showed a number of spots in thin-layer chromatography.ConclusionsIn conclusion, lanthanum chloride has been employed as a novel and efficient catalyst for the synthesis of benzimidazoles in good yields from o-phenylenediamine and a wide variety of aldehydes. All of the reactions were carried out in the presence of lanthanum chloride (10 mol%) in acetonitrile at room temperature.

Highlights

We report the synthesis of benzimidazoles using lanthanum chloride as an efficient catalyst
Benzimidazole nucleus is found in a variety of naturally occurring compounds such as vitamin B12 and its derivatives; it is structurally similar to purine bases
Benzimidazoles and its derivatives represent one of the most biologically active classes of compounds, possessing a wide spectrum of activities, and these are well documented in the literature

Summary

Introduction

We report the synthesis of benzimidazoles using lanthanum chloride as an efficient catalyst. One-pot synthesis of 2-substituted benzimidazole derivatives from o-phenylenediamine and a variety of aldehydes were developed under mild reaction conditions. Benzimidazole nucleus is found in a variety of naturally occurring compounds such as vitamin B12 and its derivatives; it is structurally similar to purine bases. Benzimidazoles and its derivatives represent one of the most biologically active classes of compounds, possessing a wide spectrum of activities, and these are well documented in the literature. They show selective nonpeptide luteinizing hormone-releasing hormone antagonist, lymphocytespecific kinase inhibitor, N-methyl-D-aspartate antagonist, 5-liopoxygenase inhibitor, NS5B polymerase inhibitor (Figure 1), neuropeptide YY1 receptor antagonist, nonpeptide thrombin inhibitor, γ-aminobutyric acid receptor, factor Xa inhibitor, and poly (ADP-ribose) polymerase inhibitor.

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Results

Conclusion