Series Of Imidazole Derivatives Research Articles

Cu (II)-catalyzed: synthesis of imidazole derivatives and evaluating their larvicidal, antimicrobial activities with DFT and molecular docking studies

This paper deals with the evaluation of novel imidazole molecules for their antimicrobial and larvicidal activities. A series of imidazole derivatives 1(a–f) and 2(a–e) were prepared by the Mannich base technique using a Cu(II) catalyst. The Cu(phen)Cl2 catalyst was found to be more effective than other methods. FTIR, elemental analyses, mass spectrometry, 1H NMR, and 13C NMR spectroscopy were performed to elucidate the structures of the synthesised compounds. Antimicrobial and larvicidal activities were investigated for all compounds. The antibacterial activity of compounds (2d) and (2a) were highly active in S.aureus (MIC: 0.25 μg/mL) and K.pneumoniae (MIC: 0.25 μg/mL) compared to ciprofloxacin. Compound (1c) was significantly more effective than clotrimazole in C.albicans (MIC: 0.25 μg/mL). Molecular docking studies of compound 2d showed a higher binding affinity for the 1BDD protein (− 3.4 kcal/mol) than ciprofloxacin (− 4.4 kcal/mol). Compound 1c had a higher binding affinity (− 6.0 kcal/mol) than clotrimazole (− 3.1 kcal/mol) with greater frontier molecular orbital energy and reactivity properties of compound 1c (∆E gap = 0.13 eV). The activity of compound 1a (LD50: 34.9 μg/mL) was more effective in the Culex quinquefasciatus than permethrin (LD50: 35.4 μg/mL) and its molecular docking binding affinity for 3OGN protein (− 6.1 kcal/mol). These newly synthesised compounds can act as lead molecules for the development of larvicides and antibiotic agents.

The combination of multi-approach studies to explore the potential therapeutic mechanisms of imidazole derivatives as an MCF-7 inhibitor in therapeutic strategies.

Breast cancer covers a large area of research because of its prevalence and high frequency all over the world. This study is based on drug discovery against breast cancer from a series of imidazole derivatives. A 3D-QSAR and activity atlas model was developed by exploring the dataset computationally, using the machine learning process of Flare. The dataset of compounds was divided into active and inactive compounds according to their biological and structural similarity with the reference drug. The obtained PLS regression model provided an acceptable r 2 = 0.81 and q2 = 0.51. Protein-ligand interactions of active molecules were shown by molecular docking against six potential targets, namely, TTK, HER2, GR, NUDT5, MTHFS, and NQO2. Then, toxicity risk parameters were evaluated for hit compounds. Finally, after all these screening processes, compound C10 was recognized as the best-hit compound. This study identified a new inhibitor C10 against cancer and provided evidence-based knowledge to discover more analogs.

New imidazole derivatives as aromatase inhibitor: Design, synthesis, biological activity, molecular docking, and computational ADME-Tox studies

In this study, a series of imidazole derivatives was designed, synthesized, and evaluated for in vitro biological activity on the human breast cancer cell line MCF7 by MTT assay. To determine the selectivity of the compounds, their cytotoxic effects on the L929 (healthy mouse fibroblast) cell line were also investigated. Compounds 1a, 1b, and 1d were found to be more effective than the reference drug cisplatin against the MCF7 cell line. It is seen that the cytotoxic effects of the compounds on the L929 cell line are quite low, and the compounds are found to be highly selective. The inhibition potentials of the compounds 1a, 1b, 1d, and 1k which were effective on the MCF7 cell line, and on the aromatase enzyme were evaluated and it was found that the compounds had similar effects to the reference drug letrozole. Further, the interactions between the best active compounds and the human aromatase cytochrome P450 (CYP) enzyme were analyzed through a molecular docking study. The findings suggest that these compounds could be a promising candidate for the creation of a new family of non-steroidal aromatase inhibitors. Finally, computational ADME-Tox studies of compounds 1a, 1b, 1d, and 1k were performed and found to have the appropriate profile.

PROSPECTS FOR THE CHEMISTRY OF IMIDAZOLE DERIVATIVES (Review)

The problem of creating new effective domestic pharmacological preparations, including the development of the methods for obtaining biologically active substances in compliance with the “green chemistry” principles, are among the priority areas for the development of chemical science. The choice of an initial molecule, which carries the potential of biological activity, is the guarantor of a successful experimental search. Imidazole derivatives occupy a unique place in the medicinal chemistry. An imidazole cycle is part of the natural compounds such as histamine, biotin, some alkaloids and nucleic acids, and is a structural fragment of medicinal preparations. The goalof the present review is to analyze the publications on the chemistry of imidazole derivatives with an emphasis on the methods of obtaining biologically active and other practically useful molecules with an obligatory imidazole cycle. The objects of the study:imidazole derivatives. The examples of the routes of synthesizing imidazole derivatives, as well as the compounds of interest for the medicinal chemistry, agriculture, and other fields, which have been published in the scientific and technical literature since 2000, have been presented. Conclusion.The studies in the field of searching for new highly effective preparations among imidazole derivatives are relevant and promising. The most important stage in this search is the directed synthesis of the substances with the specified, practically useful properties. The range of new practically useful substances in the series of imidazole derivatives has been significantly expanded and replenished thanks to the modern modifications of the classical methods of their obtaining.

QSPR models to predict quantum chemical properties of imidazole derivatives using genetic algorithm–multiple linear regression and back‐propagation–artificial neural network

AbstractImidazole derivatives are the foundation of different types of drugs with a wide range of biological activities. In this study, the genetic algorithm–multiple linear regression (GA–MLR), and backpropagation–artificial neural network (BP–ANN) were applied to design QSPR models to predict the quantum chemical properties like the entropy (S) and enthalpy of formation (∆Hf) of imidazole derivatives. In order to draw molecular structure of 84 derivative compounds Gauss View 05 program was used. These structures were optimized at DFT‐B3LYP/6‐311G* level with Gaussian09W. The Dragon software was used to calculate a set of different molecular descriptors, and the genetic algorithm procedure and backward stepwise regression were applied for the selection of descriptors. The resulting quantitative GA–MLR model of ∆Hf, showed that there is good linear correlation between the selected descriptors and ∆Hf of compounds. Also the results show that the BP–ANN model appeared to be superior to GA–MLR model for prediction of entropy. Different internal and external validation metrics were adopted to verify the predictive performance of QSPR models. The predictive powers of the models were found to be acceptable. Thus, these QSPR models may be useful for designing new series of imidazole derivatives and prediction of their properties.

Computational study of the therapeutic potentials of a new series of imidazole derivatives against SARS-CoV-2

Owing to the urgent need for therapeutic interventions against the SARS-coronavirus 2 (SARS-CoV-2) pandemic, we employed an in silico approach to evaluate the SARS-CoV-2 inhibitory potential of newly synthesized imidazoles. The inhibitory potentials of the compounds against SARS-CoV-2 drug targets - main protease (Mpro), spike protein (Spro) and RNA-dependent RNA polymerase (RdRp) were investigated through molecular docking analysis. The binding free energy of the protein-ligand complexes were estimated, pharmacophore models were generated and the absorption, distribution, metabolism, excretion and toxicity (ADMET) properties of the compounds were determined. The compounds displayed various levels of binding affinities for the SARS-CoV-2 drug targets. Bisimidazole C2 scored highest against all the targets, with its aromatic rings including the two imidazole groups contributing to the binding. Among the phenyl-substituted 1H-imidazoles, C9 scored highest against all targets. C11 scored highest against Spro and C12 against Mpro and RdRp among the thiophene-imidazoles. The compounds interacted with HIS 41 - CYS 145 and GLU 288 – ASP 289 – GLU 290 of Mpro, ASN 501 of Spro receptor binding motif and some active site amino acids of RdRp. These novel imidazole compounds could be further developed as drug candidates against SARS-CoV-2 following lead optimization and experimental studies.

Hydrogen bonding framework in imidazole derivatives: Crystal structure and Hirshfeld surface analysis

A series of imidazole derivatives (1-3) were synthesized with three component reaction among benzil, ammonium acetate and formaldehyde/aromatic aldehyde at 110 °C without a catalyst and solvent. These synthesized imidazole derivatives have shown intermolecular hydrogen bonding such as N-H···N and O-H···N. The imidazole 1 and 2 exhibited N-H···N intermolecular hydrogen bonding while imidazole 3 exhibited O-H···N intermolecular hydrogen bonding. The hydrogen bonds in imidazoles were studied by X-ray crystallography and Hirshfeld Surface Analysis at dnorm surface which show the visible red spots, indicated for hydrogen bonds. Further, Hirshfeld surface analysis also shows the percentage of all intermolecular interactions.

NiO nanocomposites/rGO as a heterogeneous catalyst for imidazole scaffolds with applications in inhibiting the DNA binding activity.

Herein, we report a facile approach to synthesize a new highly versatile heterogeneous catalyst by spontaneous aerial oxidation based on nickel oxide nanocomposites immobilized on surface-functionalized reduced graphene oxide sheets. NiO nanocomposite/reduced graphene oxide (rGO-NiO-NC) is a highly efficient, cost-effective, reusable, selective, and eco-friendly nano-catalyst that does not lose any activity even after five reaction cycles. Nickel loading on the rGO-NiO nanocomposite was found to be 3.3 at%, which contributes to the effective and efficient use of rGO-NiO-NCs as a nano-catalyst for the synthesis of imidazole derivatives. Consequently, a series of imidazole derivatives were synthesized, catalyzed by rGO-NiO-NCs, in 60 min with high yields (86% to 96%) under green conditions. Furthermore, the present synthetic methodology was used for the synthesis of highly aromatic imidazole derivatives (B1-B3) whose calf thymus-DNA binding affinities suggest their superior inhibition ability to displace ethidium bromide (EB), which was further confirmed by molecular docking studies. Additionally, the green chemistry matrix of the synthesis reaction was found to be very close to ideal values, such as carbon efficiency (82.32%), E-factor (0.51), atom economy (77.86%), process mass intensity (1.51), and reaction mass efficiency (66.14%).

The cytotoxic activities of imidazole derivatives prepared from various guanylhydrazone and phenylglyoxal monohydrate

A series of imidazole derivatives were synthesized from two-component condensation reaction of phenylgloxal monohydrate with guanylhydrazone. They were characterized by spectroscopic and analytical techniques. The in vitro anticancer evaluation of these compounds was done on human breast cancer (MCF-7) and human liver cancer (HepG2) cell lines using the MTT assay method. Most of the newly synthesized compounds displayed cytotoxic activity against these cancerous cells. In fact, compounds 3a, 3e, and 3 h exhibited more cytotoxic activities than the positive control drugs, fluro-5, and irinocam, against the MCF-7 cell line. Almost all the compounds, except for three, 3b, 3d, and 3f, gave more cytotoxic results than cisplatin. Therefore, these compounds could be considered for further development as anticancer drug candidates.

Identification of novel imidazoles as IDO1 inhibitors through microwave-assisted one-pot multicomponent reactions.

A series of imidazole derivatives were designed following rational drug design, and synthesized through microwave-assisted one-pot multicomponent reactions. These compounds are produced in large quantities, and are known to be tolerant toward a variety of substrates, thus providing target molecules in a single step within a short time. These compounds were further tested for their ability to inhibit indoleamine-2,3-dioxygenase 1 (IDO1). The most promising compound thus obtained is 4o, which displayed IC50 values of 0.82 μΜ. Further in vivo assessment indicated that 4o could reduce the kynurenine levels in plasma by 42.3% in 4 hr, indicating that the compound could act as a promising lead compound for further investigations.

Synthesis, Characterization, and Molecular Docking Study of Some Novel Imidazole Derivatives as Potential Antifungal Agents

The azole pharmacophore is still regarded as a viable lead structure for the synthesis of more effective antifungal agents. In this study, two novel series of imidazole derivatives containing dithiocarbamate (5a–5g) and (benz)azolethiol (6a–6n) side chains that are structurally related to the famous antifungal azole pharmacophore were synthesized, and the structures of them were characterized by spectral (IR, 1H NMR, 13C NMR, and MS spectra) analyses. The synthesized compounds were screened in vitro antifungal activity against pathogenic strains fungi. Theoretical ADME (absorption, distribution, metabolism, and excretion) predictions were calculated for final compounds. A molecular docking study of the most active compound with target “lanosterol 14α‐demethylase” (CYP51) was performed to unravel the mode of antifungal action. Compound 5e, which features imidazole and 4‐methoxybenzyl piperazine scaffolds, showed the most promising antifungal activity with an MIC50 value of 0.78 μg/mL against C. krusei. Effect of the compound 5e against ergosterol biosynthesis was observed by LC–MS–MS method, which is based on quantification of ergosterol level in C. krusei.

A Convenient, Rapid Microwave Assisted Synthesis of Some Novel Imidazole Derivatives and Their Antimicrobial Activity

A series of imidazole derivatives were synthesized by condensation of, differently substituted 4-benzylidene-2phenyloxazol-5(4H)-one and ammonia, which on further reaction with barbituric acid produces the final products (substituted 5-((5-oxo-2-phenyl-4,5-dihydro-1H-imidazol-4-yl)methyl)pyrimidine-2,4,6(1H,3H,5H)triones) 3(a-f). The structures of the newly synthesized compounds were supported by IR, 1H NMR, 13C NMR and MASS spectral data. All the reactions were carried out by environmental benign, efficient and extremely fast procedure microwave assisted synthesis. The derivatives of these moieties were screened for antibacterial and antifungal activity. It was seen that the compounds showed more antibacterial activity towards the test organisms S. pyogenus and S. aureus and significant activity against all strains of fungi.

Imidazole-Based [2 + 1] Re(I)/99mTc(I) Complexes as Isostructural Nuclear and Optical Probes

The synthesis, stability, and photophysical properties of [2 + 1] Re(I)/Tc(I) complexes derived from bipyridine and a series of imidazole derivatives were investigated as a means of identifying complexes suitable for creating targeted isostructural optical/nuclear molecular imaging probes. To prepare the desired complexes, [Re(CO)3(H2O)3]Br was combined with 2,2'-bipyridine (bipy) to give [Re(CO)3(bipy)Br], which in turn was converted to the desired complexes by treatment with functionalized imidazoles, yielding crystal structures of two new Re complexes. The corresponding (99m)Tc complexes [(99m)Tc(CO)3(bipy)(L)](+) (L = imidazole derivatives) were prepared by combining [(99m)Tc(CO)3(bipy)(H2O)]Cl with the same series of ligands and heating at 40 or 60 °C for 30 min. Quantitative transformation to the final products was confirmed in all cases by HPLC, and the nature of the complexes was verified by comparison to the authentic Re standards. Incubation in saline and plasma, and amino acid challenge experiments showed that N-substituted imidazole derivatives, bearing electron donating groups, exhibited superior stability to analogous metal complexes derived from less basic ligands. Imaging studies in mice revealed that with the appropriate choice of monodentate ligand, it is possible to prepare robust [2 + 1] Tc complexes that can be used as the basis for preparing targeted isostructural optical and nuclear probes.

Tunable single and dual emission behavior of imidazole fluorophores based on D-π-A architecture

• A series of imidazole derivatives were synthesized and characterized. • Influence of solvent polarity on spectral behavior was investigated. • Kamlet–Taft and Catalán solvent parameters were used to analyze the solvatochromism. • Interplay between LE and ICT state was analyzed. • TD-DFT method was used to study the geometric and electronic structure of molecules. A series of three D-π-A molecules containing 4,5-diphenyl-1H-imidazole moiety as the donor (D) with cyanoacetic acid, rhodanine-3-acetic acid and 4-nitrophenyl acetonitrile as the acceptor (A) connected by a biphenyl bridge have been synthesized and characterized. Crystallography of BIC shows C4-phenyl group to be twisted nearly perpendicular to the imidazole unit and the remaining groups are in plane. The absorption spectra of the compounds are dominated by intramolecular charge transitions that arise from the imidazole core to the acceptor groups. The compounds display distinct dual and single emission behavior in different solvent environments, namely locally excited (LE ∼ 430 nm) and intramolecular charge transfer (ICT ∼ 550 nm). The Lippert–Mataga analysis suggested that the excited state dipole moment of ICT band is higher than the LE band. The influence of general and specific solvent effects on photophysical properties of the fluorophores was discussed with Catalán four parameter and Kamlet–Taft three parameter solvent scales. These results suggest that the major influence from solvent dipolarity takes part in a prominent role on changing the emission behavior of the compounds. The quantum yield of the compounds ranged between 0.07 and 0.55 in different solvents and it was shown to depend on the substitution pattern most notably that based on acceptor groups. All the compounds exhibit two lifetimes in the singlet excited state corresponding to LE state (short lived) and ICT state (long lived). In addition, the triplet state absorption properties of the compounds are also investigated by transient absorption measurement. The geometric structure and electronic structure of the molecules in the ground state is studied with DFT methods, whereas the energies of the lowest singlet excited states are calculated by employing TD-DFT methods. The results show that most prominent bands in acetonitrile solvent with higher oscillator strength for BIC, BIN and BIR are due to LE.

Synthesis and biological evaluation of di- and tri-substituted imidazoles as safer anti-inflammatory-antifungal agents

PURPOSE:In view of the potential pharmacophoric nature of imidazole nucleus, two series of imidazole derivatives, 2,4-disubstituted-1 H-imidazoles (2a-m) and 1,2,4-trisubstituted-1 H-imidazoles (3a-m), were synthesized with an aim of obtaining dual acting compounds i.e., anti-inflammatory and antifungal agents.MATERIALS AND METHODS:The title compounds were synthesized from 4-methoxyphenyl glyoxal (1) following multistep synthesis, and their structures were established on the basis of modern analytical techniques (IR, NMR and MS). The synthesized imidazoles were tested for their in vivo anti-inflammatory activity. In addition to that, some compounds were also evaluated for their analgesic and ulcerogenic effects. The compounds were also evaluated for their in vitro antifungal activity.RESULTS:Di- and tri-substituted imidazole derivatives (2a-m and 3a-m) were successfully synthesized. In in vivo anti-inflammatory test, six compounds (2 h, 2 l, 3 g, 3 h, 3 l and 3 m) exhibited good anti-inflammatory activity (49.58 to 58.02% inhibition) with minimal GI irritation (severity index; 0.17 to 0.34). These compounds were also tested for their analgesic activity and showed appreciable protection (40.53 to 49.60% protection) against saline-induced writhing test. Indomethacin was used as standard drug for comparison. In antifungal test, two compounds (3 h and 3 l) displayed appreciable antifungal activity (MIC; 12.5 μg mL-1) against the fungal strains tested.CONCLUSION:Two compounds, 2-(4-nitrophenyl)-4-(4-methoxyphenyl)-1-phenyl-1H-imidazole (3 h) and 2,4-di-(4-methoxyphenyl)-1-phenyl-1H-imidazole (3 l), emerged as lead compounds having dual biological activities; good anti-inflammatory as well as antifungal effect with lesser GI irritation.

One-pot Synthesis of 2,4,5-trisubstituted Imidazoles Catalyzed by Lipase

A simple and efficient protocol of synthesizing 2,4,5-trisubstituted imidazoles has been developed using lipase as a novel catalyst under mild conditions. A series of imidazole derivatives were synthesized with good yields. The probable enzymatic mechanism was proposed. This method expands the catalytic scope of lipase and provides a novel method to prepare imidazole derivatives.

Synthesis of Novel Imidazole Compounds and Evaluation of Their Antimicrobial Activity

Imidazoles are an important class of heterocycles and include many substances of both biological and chemical interest. Insertion of the imidazole nucleus is an important synthetic strategy in drug discovery. Imidazole drugs have broad applications in many areas of clinical medicine. These are currently used as tools in pharmacological studies. The important therapeutic properties of imidazole related drugs have encouraged the medicinal chemists to synthesize and test a large number of novel molecules. In this investigation, it was of interest to synthesize imidazole by refluxing 9, 10-phenenthraquinone with aryl aldehyde, primary amines and ammonium acetate in the presence of glacial acetic acid and a novel series of imidazole derivatives. The structures of the compounds have been established on the basis of spectral analytical data. All the derivatives have been screened for their antimicrobial activities at the 100µg/ml and 200µg/ml against Candida albicans. © 2011 IGJPS. All rights reserved

Quantitative structure activity relationship (QSAR) studies on a series of imidazole derivatives as novel ORL1 receptor antagonists

QSAR studies were performed on a series of imidazole derivatives as novel Orl1 receptor antagonists. Imidazole derivatives have been analyzed in relation to their physicochemical and molecular properties. The activities of the compounds were found to be significantly correlated with the physicochemical parameters such as density (D), surface tension (St), index of refraction (Ior), balaban index (J) and partition coefficient (LogP). It was found that the presence of group at R1 position was conducive for the inhibitory activity. The results are critically discussed on the basis of regression data and cross validation techniques. Poglani factor Q and the results of LOO (leave one out) method confirms the reliability and predictability of the proposed models.

Synthesis and in vitro trichomonicidal, giardicidal and amebicidal activity of N-acetamide(sulfonamide)-2-methyl-4-nitro-1 H-imidazoles

Two new series of imidazole derivatives (acetamides: 1– 8 and sulfonamides: 9– 15) were synthesized using a short synthetic route. Compound 1 as well as the intermediate 16g were characterized by X-ray crystallography. Imidazole derivatives 1– 15 were tested in vitro against three unicellular parasites ( Giardia intestinalis, Trichomonas vaginalis and Entamoeba histolytica) in comparison with benznidazole (Bzn) and metronidazole. Compound 1 [ N-benzyl-2-(2-methyl-4-nitro-1 H-imidazol-1-yl)acetamide] was 2 times more active than Bzn against T. vaginalis and G. intestinalis and it was as active as Bzn against E. histolytica. Sulfonamides showed selective toxicity against E. histolytica over the other parasites. Toxicity assay showed that all compounds are non-cytotoxic against MDCK cell line. The results revealed that compounds 1– 15 have antiparasitic bioactivity in the micromolar range against the parasites tested, and could be considered as benznidazole bioisosteres.

Design and optimization of imidazole derivatives as potent CXCR3 antagonists

A series of imidazole derivatives have been designed and optimized for CXCR3 antagonism, pharmacokinetic properties, and reduced formation of glutathione conjugates. Our efforts led to the discovery of potent CXCR3 antagonists with good pharmacokinetic properties. These compounds are useful tools for in vivo studies of CXCR3 function.