Synthesis and Biological Evaluation of Benzimidazole Derivatives as Antimicrobial Agents (original) (raw)
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Current drug discovery technologies, 2018
Due to the appearance of communicable microbial diseases and the toxicity related with presently used several antimicrobials such as β-lactam antibiotics, tetracyclines, quinolones, macrolides, glycopeptides (vancomycin) etc, demand for new antimicrobial agents has become great concern in new technologies to improve efficacy and safety. In search of new antimicrobial agents with higher potency, some N-substituted benzimidazole derivatives (4, 5a-5h & 6) were obtained by chloroacetylation of benzimidazole followed by reaction with different amines which were characterized by spectroscopic methods. All the target compounds were evaluated for their antibacterial and antifungal activity against microorganisms using two fold serial dilution method. Among the compounds evaluated, compounds 4 and 5d exhibited potent activity against Bacillus thuringiensis and Candida albicans while showed moderate activity against Escherischia coli when compared to amoxicillin and fluconazole. Compound 5a ...
Benzimidazole: A short review of their antimicrobial activities
International Current Pharmaceutical Journal, 2012
Benzimidazole is the heterocyclic compound formed from benzene and imidazole ring containing nitrogen, oxygen sulphor and its derivatives are of wide interest because of their diverse biological activity and clinical applications, they are remarkably effective compounds both with respect to their inhibitory activity and their favourable selectivity ratio. Reported nucleus is a constituent of vitamin-B12. Benzimidazoles are regarded as a promising class of bioactive heterocyclic compounds that exhibit a range of biological activities like anti-microbial, anti-viral, anti-diabetic, anticancer activity, numerous anti-oxidant, anti-parasitic, anti-helmintics, anti-proliferative, anti-HIV, anti-convulsant, anti-inflammatory, anti-hypertensive, anti-neoplastic, proton pump inhibitor and anti-trichinellosis. Benzimidazoles exhibit significant activity as potential antitumor agents, smooth muscle cell proliferation inhibitors, a treatment for intestinal cystitis, and in diverse area of chemistry. Some of the important benzimidazole derivatives have been reported as thyroid receptor agonist gonadotropin releasing hormone receptor antagonists, non-nucleoside HIV-1 reverse transcriptase inhibitors and interestingly alkynylbenzimidazoles as modulators of metabotropic glutamate receptors. The imidazole core is a common moiety in a large number of natural products and pharmacologically active compounds. The synthesis of novel benzimidazole derivatives remains a main focus of medicinal research. This comprehensive overview summarizes the chemistry of different derivative of substituted benzimidazole along with their anti-microbial activity containing anti-malarial anti-fungal, anti-bacterial, anti-viral activities.
IJC-B Vol.60B(01) [January 2021], 2021
Benzimidazole is the heterocyclic compound formed by the fusion of benzene and imidazole ring. Benzimidazole analogs are of great significance because of their clinical application and biological activity. Benzimidazoles are considered as an optimistic class of bioactive heterocyclic compound that possesses a range of biological activities. We have synthesized five substituted Benzimidazole derivative using on both microwave irradiation and conventional heating method. The newly synthesized compounds are characterized by IR, NMR and Mass spectra analysis. In the present study, we have reported the synthesis, spectral studies and biological evaluation of some benzimidazole derivatives. Benzimidazole play important role in medical field with so many pharmacological activities such as antimicrobial, anti bacterial, etc. The potency of this clinically useful drug in treatment in microbial action and other activities has encouraged the development of some more potent and significant compounds.
2012
The synthetic pathway for preparation of different title compounds is shown in Scheme 1. Condensation of ophenylenediamine with benzaldehyde afforded 2-phenyl-1H-benzimidazole (1). Compound 1 on chloroesterification in presence of catalytical amount of potassium hydroxide afforded ethyl (2-phenyl-1H-benzimidazol-1-yl) acetate (2). The formation of compound 2 was evidenced by appearance of a singlet at δ 4.89 and a multiplet at δ 7.86-7.26 ppm due to NCH 2 and Ar-H, respectively. In the 1 H NMR spectra of compound 2, the peak at δ 4.29-4.23 ppm was observed due to CH 2 and a peak at δ 1.28-1.24 ppm was due to the CH 3 group of compound 2. Furthermore, in the IR spectra, the bands at 1743 cm-1 (>C=O of ester), 2960-2880 cm-1 (-CH 2, CH 3) and 1250 cm-1 (C-O-C) also confirmed the formation of compound 2. The amination of compound 2 with hydrazine hydrate yielded 2-(2-phenyl-1H-benzimidazol-1-yl) acetohydrazide (3). The formation of compound 3 was evidenced by appearance of a signal at δ 8.14 and 2.11 ppm due to-NH and-NH 2 , respectively. The IR spectral bands at 3352-3302 cm-1 (-NHNH 2) also confirmed the formation of compound 3. Compound 3 on treatment with selected aromatic aldehydes in presence of glacial acetic acid in ethanol as a reaction mediator afforded N'-(substituted benzylidene)-2-[2-(substituted phenyl)-1H-benzimidazol-1-yl] acetohydrazide derivatives (4a-e). The purity of the compounds was monitored by TLC and the structures of all the derivatives were assigned by IR, 1 H NMR and mass spectroscopic data, which are consistent with the proposed molecular structures.
SYNTHESIS AND ANTIMICROBIAL EVALUATIONS OF SOME NOVEL DERIVATIVES OF BENZIMIDAZOLE
N-Acyliminium reagents derived from benzimidazole have been successfully used in reactions with active methylene nucleophiles. A series of cyclic enaminoketones or dimedone were selectively amidoalkylated at the α-carbon atom of the enaminone. The new 2-substituted derivatives of 2,3-dihydrobenzimidazole are interesting both from synthetic point of view and as potential bioactive compounds. All the synthesized benzimidazole derivatives were assayed for antimicrobial activity using standardized tests (DM and DDM) against seven strains microorganisms. Eight compounds displayed antimicrobial activity against Staphylococcus aureus, Enterobacter aerogenes, Candida albicans.
2015
A library of 53 benzimidazole derivatives, with substituents at positions 1, 2 and 5, were synthesized and screened against a series of reference strains of bacteria and fungi of medical relevance. The SAR analyses of the most promising results showed that the antimicrobial activity of the compounds depended on the substituents attached to the bicyclic heterocycle. In particular, some compounds displayed antibacterial activity against two methicillin-resistant Staphylococcus aureus (MRSA) strains with minimum inhibitory concentrations (MICs) comparable to the widely-used drug ciprofloxacin. The compounds have some common features; three possess 5-halo substituents; two are derivatives of (S)-2-ethanaminebenzimidazole; and the others are derivatives of one 2-(chloromethyl)-1Hbenzo[d]imidazole and (1H-benzo[d]imidazol-2-yl)methanethiol. The results from the antifungal screening were also very interesting: 23 compounds exhibited potent fungicidal
Synthesis and Evaluation of Selected Benzimidazole Derivatives as Potential Antimicrobial Agents
Molecules, 2015
A library of 53 benzimidazole derivatives, with substituents at positions 1, 2 and 5, were synthesized and screened against a series of reference strains of bacteria and fungi of medical relevance. The SAR analyses of the most promising results showed that the antimicrobial activity of the compounds depended on the substituents attached to the bicyclic heterocycle. In particular, some compounds displayed antibacterial activity against two methicillin-resistant Staphylococcus aureus (MRSA) strains with minimum inhibitory concentrations (MICs) comparable to the widely-used drug ciprofloxacin. The compounds have some common features; three possess 5-halo substituents; two are derivatives of (S)-2-ethanaminebenzimidazole; and the others are derivatives of one 2-(chloromethyl)-1Hbenzo[d]imidazole and (1H-benzo[d]imidazol-2-yl)methanethiol. The results from the antifungal screening were also very interesting: 23 compounds exhibited potent fungicidal
In Search of the Antimicrobial Potential of Benzimidazole Derivatives
Polish Journal of Microbiology, 2016
A broad series of 4,5,6,7-tetrahalogenated benzimidazoles and 4-(1H-benzimidazol-2-yl)-benzene-1,3-diol derivatives was tested against selected bacteria and fungi. For this study three plant pathogens Colletotrichum sp., Fusarium sp., and Sclerotinia sp., as well as Staphylo coccus sp., Enterococcus sp., Escherichia sp., Enterobacter sp., Klebsiella spp. , and Candida spp. as human pathogens were used. MIC values and/or area of growth reduction method were applied in order to compare the activity of the synthesized compounds. From the presented set of 22 compounds, only 8, 16, 18 and 19 showed moderate to good inhibition against bacterial strains. Against Candida strains only compound 19 with three hydroxyl substituted benzene moiety presented high inhibition at nystatin level or lower.
Evaluation of Antifungal and Antibacterial Activity of Some New Benzimidazole Derivatives
Latin American Applied Research - An international journal
The extensive use of antifungal drugs and their resistance against fungal infections have led to discover new antimicrobial compounds. We previously described synthesis of some new derivatives of 2-methylbenzimidazole (1a-5a) and 5,6dimethylbenzimidazol (1b-5b). Here we evaluated the antimicrobial activities of these compounds against different species of micro organisms including gram positive and gram negative bacteria as well as fungi. Broth micro-dilution method as recommended by clinical and laboratory standard institute (CLSI) was used for this purpose. The results show compounds 2-Methyl-1-(3-methylbenzyl)-1H-benzo [d]imidazole (5a) and 5,6-Dimethyl-1-(3-methyl benzyl)-1H-benzo[d]imidazole (5b) had the best antifungal activity against the examined fungi and gram positive bacteria. Moreover these two compounds inhibited the growth of azole resistant strains. By comparison the relationship between the structures and activities of the tested compounds revealed that the presence ...
Synthesis and Characterization of Benzimidazole Derivatives for Antimicrobial Property
IJPSM, 2021
Benzimidazoles are an important class of compounds with a wide spectrum of biological activity ranging from anti-hypertensive, anti-viral, anti-microbial, antitumor and anthelmintic activity. Benzimidazole rings are the most important nitrogen-containing heterocycles, which are widely explored and utilized by the pharmaceutical industry for drug discovery. Due to their special structural features and electron-rich environment, Benzimidazole containing drugs bind to a variety of therapeutic targets, thereby exhibiting a broad spectrum of bioactivities. Numerous benzimidazole based drugs have been extensively used in the clinic to treat various types of diseases with high therapeutic potential. The main objective of present work was to study the anti-microbial activity of the Benzimidazole derivatives. A series of benzimidzole derivatives have been synthesized and identified. The compounds were synthesized by using ethyl acetate and benzene as starting material. The series of 1, 2-disubstituted benzimidazoles containing pyrimidine and other functional groups was prepared which provides advantages such as, easy workup and high yield. All reagents used for synthesis were of synthetic grade. Purification of all compounds was done by thin layer chromatography using silica gel G as absorbent on glass plate using acetate: benzene (6:4 v/v %), Toluene: Acetone (8:2 v/v %) and Ethyl Acetate: n-Hexane (6:4 v/v %) as mobile phase. Compounds were detected by using iodine vapor as detecting agent. All compounds show single spot. All the newly synthesized compounds were characterized by IR spectral study. The compounds were investigated for their antimicrobial activity against clinical standard drug Ciprofloxacin. The anti-microbial study of the synthesized derivative was done Broad panels of bacterial and fungal strains were used for testing the antimicrobial properties of the synthesized molecules III1-13. The compounds III 1 (m-NO 2), III 2 (p-NO 2), III 3 (m-Cl), III 4 (3-F-4-Cl) and III 9 (p-OCH 3) showed excellent activity (62.5 μg/ml), even better than ciprofloxacin.