A Review on the Modern Synthetic Approach of Benzimidazole Candidate

Benzimidazole structure contains imidazole ring fused with phenyl ring at 4- and 5-position. The mono and disubstituted derivatives of benzimidazole are very interesting heterocyclic organic molecules, synthesized by a simple nucleophilic substitution reaction and condensation method between o-phenylenediamine with carbonyl compound under different conditions are reported, and as time passed away, the method also be reported in favor of the environment-friendly with good yield product. We cover the literature up to the end of 2019 in which very recently reported synthetic route to access benzimidazole scaffolds are discussed. We are focus on the evaluation of synthetic route to construct monosubstituted-benzimidazole (MSBs) and disubstituted-benzimidazoles (DSBs), via various methods involving condensation, cyclization or employing green chemistry aspect such as utilizing solvent-free conditions, metal-free conditions, or using nanoparticle catalyst etc. Benzimidazoles found in the natural system display a wide range of pharmaceutical properties have been reported. The scaffolds are characterized as structurally potential ligands which can bind to different receptor sites for the discovery of various immerging drugs. Therefore, benzimidazole is recognized as a potent scaffold in the pharmaceutical industry and diverse synthetic pathways have been developed to prepare its functionalized derivatives which are described in this review.