Benzimidazole

The use of heterocyclic compounds in field of medicinal chemistry is increasing day by day due to various reasons like heterocyclic compounds are included in the structure of many biochemical materials, which are essential for life. Nucleic acid, many naturally occurring pigments like chlorophyll, vitamins and antibiotics contains heterocyclic nucleus. Modern society is also dependent on synthetic heterocycles for use as drugs, pesticides and dyes. The work embodied in this article relates to benzimidazole as it is a versatile heterocycle which exhibit broad range of biological activities. Benzimidazoles (known as o-phenylenediamine derivatives) are mostly synthesized from o-phenylenediamines. This ring system is present in numerous anti-protozoal, anti-helmintics, anti-HIV, anti-convulsant, anti-inflammatory, anti-neoplastic, and anti-ulcer agents. Several benzimidazoles such as albendazole, mebendazole, flubendazole, fenbendazole, omeprazole, lansoprazole, and clofazone are used in therapy. In this review, various antimicrobial benzimidazoles were summarized & reported. In addition this review highlights the antimicrobialpotency of benzimidazole to medicinal world.

In the present study novel series of 3-((3-((6-benzoyl-1H-benz[d]imidazol-2-yl) amino)-5-mercapto-4H-1, 2, 4-triazol-4-yl)imino)substituted indolin-2-ones have been synthesized in good yields and characterized by IR, NMR and Mass spectral analyses. Compounds were evaluated for their preliminary in vitro cytotoxic activity against HCT-116 (colon), MCF-7 (breast), HeLa (cervical) and HepG2 (hepatocellular) cancer cell lines by standard MTT assay method, antioxidant activity by standard DPPH assay method and also were screened for  in vitro anti-inflammatory activity.

Tuberculosis is a serious threat to public health throughout the world. Schiff bases are compounds carrying the imine or azomethine (–C=N–) functional group. Recent studies report that benzimidazole based Schiff bases possess antibacterial, antimicrobial, anti-tubercular, and anti-inflammatory activities. 1,2 Further it has been known that fluoroaniline moiety can have profound and unexpected results in biological activity 19. A series of benzimidazole and fluroaniline based Schiff bases were designed and docked against crucial mtb enzyme target Glutamine synthetase1. The molecules with good docking-score and multiple interactions were chosen for synthesis. Compounds (BE1, BE2, FA-1, FA-2, and FA-3) were synthesized by reflux condensation reaction with good yield. The newly synthesized compounds were characterized by spectral methods and evaluated for anti- mycobacterial activity against tuberculosis H37RV strain. Anti-tubercular activity was carried out by using Microplate Alamar Blue Assay (MABA) method. The experimental results revealed that Compounds (BE1& BE2) showed promising anti-tubercular activity with an MIC below 0.8 mcg/mL while (FA-1, FA-2, and FA-3) showed moderate anti tubercular activity with an MIC below 6.25 and 12.5 mcg/mL. Key words: Benzimidazole, Schiff base, Fluoroaniline, Docking, Anti-tubercular.

Imidazoles are nitrogen containing heterocyclic compounds, widely present in nature. The imidazole ring is a part of several important natural products, including purine, histamine, histidine and nucleic acid. Highly substituted imidazoles derivatives belong to a crucial structural motif that is seen in many pharmaceutically and biologically interesting molecules. They have been intensively used in medicinal chemistry as drugs such as antihistaminic1, antiulcerative,2 antihelmentic,3 and antipsychotic.4 Several benzimidazoles have been reported as antiviral,7 anticoagulant,8 antiinflammatory,9 antibacterial10 and anticancer agents.11 The present work deals with the derivatization of 2-(1H-benzo[d]imidazol-2-yl)-3-oxobutanenitrile with thiazolidin-4-one, oxazolidin-4-one and azetidin-2-one and characterization. All the compounds were tested for biological activity against E. coli, S. typhi, S. aureus while streptomycin was used as standard.

In the present scheme, we have an attempt to synthesize some novel benzimidazole derivatives by substituting triazole moiety at N-1 position of benzimidazole by fusion reaction of benzimidazole-1-acetic acid with thiocarbohydrazide. The substituted triazole was refluxed with different aromatic carboxylic acid in the presence of POCl3 yield different benzimidazole derivatives, respectively. The synthesized compounds were characterized by IR, 1H-NMR and Mass spectroscopy. The compounds were screened for antibacterial (gram +ve, gram –ve bacteria) activities. Key words: Benzimidazole, thiocarbohydrazide, substituted benzoic acid, benzimidazole- 1-acetic acid