Imidazole ring is an important five-membered aromatic heterocycle widely present in natural products and synthetic molecules. The unique structural feature of imidazole ring with desirable electron-rich characteristic is beneficial for imidazole derivatives to readily bind with a variety of enzymes and receptors in biological systems through diverse weak interactions, thereby exhibiting broad bioactivities. The related research and developments of imidazole-based medicinal chemistry have become a rapidly developing and increasingly active topic. Particularly, numerous imidazole-based compounds as clinical drugs have been extensively used in the clinic to treat various types of diseases with high therapeutic potency, which have shown the enormous development value. This work systematically gives a comprehensive review in current developments of imidazole-based compounds in the whole range of medicinal chemistry as anticancer, antifungal, antibacterial, antitubercular, anti-inflammatory, antineuropathic, antihypertensive, antihistaminic, antiparasitic, antiobesity, antiviral, and other medicinal agents, together with their potential applications in diagnostics and pathology. It is hoped that this review will be helpful for new thoughts in the quest for rational designs of more active and less toxic imidazole-based medicinal drugs, as well as more effective diagnostic agents and pathologic probes.

Comprehensive Review in Current Developments of Imidazole‐Based Medicinal Chemistry

A comprehensive review in current developments of benzothiazole-based molecules in medicinal chemistry.

Structure activity relationship (SAR) study of benzimidazole scaffold for different biological activities: A mini-review

The development of novel compounds, hydrazones has shown that they possess a wide variety of biological activities viz. antimicrobial, anticonvulsant, antidepressant, anti-inflammatory, analgesic, antiplatelet, antimalarial, anticancer, antifungal, antitubercular, antiviral, cardio protective etc., Hydrazones/azomethines/imines possess-NHN = CH- and constitute an important class of compounds for new drug development. A number of researchers have synthesized and evaluated the biological activities of hydrazones. This review aims at highlighting the diverse biological activities of hydrazones.

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A review exploring biological activities of hydrazones.

The properties of benzimidazole and its derivatives have been studied over more than one hundred years. Benzimidazole derivatives are useful intermediates/subunits for the development of molecules of pharmaceutical or biological interest. Substituted benzimidazole derivatives have found applications in diverse therapeutic areas such as antiulcer, anticancer agents, and anthelmintic species to name just a few. This work systematically gives a comprehensive review in current developments of benzimidazole-based compounds in the whole range of medicinal chemistry as anticancer, antibacterial, antifungal, anti-inflammatory, analgesic agents, anti-HIV, antioxidant, anticonvulsant, antitubercular, antidiabetic, antileishmanial, antihistaminic, antimalarial agents, and other medicinal agents. This review will further be helpful for the researcher on the basis of substitution pattern around the nucleus with an aim to help medicinal chemists for developing an SAR on benzimidazole drugs/compounds.

Comprehensive Review in Current Developments of Benzimidazole-Based Medicinal Chemistry.

Antimicrobial activity and a SAR study of some novel benzimidazole derivatives bearing hydrazone moiety

Due to antimicrobial importance of benzimidazoles and hydrazones, some benzimidazolehydrazone compounds were synthesized to screen their antimicrobial activity. Structures of the synthesized compounds were elucidated by 1H-NMR, IR and ES-MS spectral data and elemental analysis. The synthesized benzimidazole-hydrazones exhibited very weak antibacterial activity. However, antifungal activity of some of the synthesized compounds was very notable against Candida species. The compounds displaying important antifungal activity were screened for their toxicity. Artemia salina 96-well assay was used to determine cytotoxicity of the compounds. Tested compounds exhibited toxicity to different extents (LD50 = 126.33−368.72 μg/mL). Nevertheless, determination of 3–14 folds higher LD50 than minimum inhibitory concentration is a significant finding, which demonstrates that the compounds display antifungal activity at non-toxic concentration.

Antimicrobial activity of a new series of benzimidazole derivatives

In this work, we synthesized fourteen different compounds which contain hydrazone bridged thiazole and pyrrole rings. For this purpose, pyrrole-2-carboxaldehydes were reacted directly with thiosemicarbazide in ethanol and then obtained thiosemicarbazones were condensed with α-bromoacetophenone derivatives (Hantzsch reaction) to give 1-substituted pyrrole-2-carboxaldehyde [4-(4-substituted phenyl)-1,3-thiazol-2-yl] hydrazones. The structures of the obtained compounds were elucidated by using IR, (1)H-NMR and FAB(+)-MS spectral data and elemental analyses results. All of the compounds were screened for their antibacterial and antifungal activities against twelve different microorganisms by using microbroth dilution method. Ketoconazole and chloramphenicol were used as standard drugs. All of the compounds showed good activity against Staphylococcus aureus and Enterococcus faecalis.

https://www.tandfonline.com/doi/pdf/10.3109/14756366.2012.688043

Synthesis and antimicrobial activity of some new hydrazone-bridged thiazole-pyrrole derivatives.

In the present study a new series of benzimidazole derivatives bearing various (benz)azolylthio moieties were synthesized so as to investigate their antimicrobial activity. Structures of the target compounds (5a-5i) were confirmed by their IR, (1) H-NMR, ES-MS spectral data, and elemental analyses. The synthesized compounds (5a-5i) exhibited poor activity against bacterial strains. On the other hand, antifungal activity of the compounds against Candida species was very significant. Brine-Shrimp lethality assay was performed for determination of toxicity of the compounds. Compounds 5a, 5c, and 5d were evaluated as non-toxic in addition to their attractive antifungal activity. However, the other compounds (5b, e-i) in the series showed toxicity to different extents.

Antimicrobial activity of a new combination system of benzimidazole and various azoles.

1-(p-Methylphenyl)-3,5-diaryl-2-pyrazoline derivatives (2a-f) were synthesized via the treatment of 1-(1H-indol-3-yl)-3-aryl-2-propen-1-ones (1a-f) with p-methylphenylhydrazine hydrochloride in hot acetic acid. The structures of these compounds were elucidated by IR, ¹H NMR, and mass spectral data and elemental analysis. These compounds were investigated for their antimicrobial activity. Brine-Shrimp lethality assay was carried out to determine the toxicity of the compounds. Compound 2e, which is the pyrazoline derivative bearing the 2,5-dichlorophenyl moiety, can be identified as the most promising agent against Klebsiella pneumoniae (ATCC 13883) and Candida glabrata (ATCC 36583) due to its inhibitory effects on K. pneumoniae and C. glabrata with a MIC value of 100 µg/mL as a non-toxic agent (LC₅₀ > 1000 µg/mL).

Hülya Karaca

Papers

Antimicrobial activity and a SAR study of some novel benzimidazole derivatives bearing hydrazone moiety

Antimicrobial activity of a new series of benzimidazole derivatives

Synthesis and antimicrobial activity of some new hydrazone-bridged thiazole-pyrrole derivatives.

Antimicrobial activity of a new combination system of benzimidazole and various azoles.

Synthesis and Biological Evaluation of Pyrazoline Derivatives Bearing an Indole Moiety as New Antimicrobial Agents