MoS2-Calix[4]arene Catalyzed Synthesis and Molecular Docking Study of 2,4,5-Trisubstituted Imidazoles As Potent Inhibitors of Mycobacterium tuberculosis

Mixed Carboxylate Ligands Bridging Tetra-Pr3+-Encapsulated Antimonotungstate: Syntheses, Structure, and Catalytic Activity for Imidazoles Synthesis

Multinuclear Pr-containing antimonotungstate [Pr4(H2O)10W6O13(mal)2(OAc)(B-α-SbW9O33)4]21- (Pr-1, mal = malate anion, OAc = acetate anion), bridged by organic carboxylic acid, was synthesized through a one-pot assembly reaction and structurally characterized. Pr-1 is composed of four [B-α-SbW9O33]9- fragments fused together by an organic-inorganic hybrid central [Pr4(H2O)10W6O13(mal)2(OAc)]15+ cluster core through 24 μ2-O atoms. Notably, the central cluster comprises unprecedented decanuclear Pr4(H2O)10W6O13 jointly decorated by two types of carboxylic acid ligands. This integration of rare earth-containing antimonotungstate with mixed organic carboxylate ligands is very rare in POMs chemistry. Pr-1 exhibits excellent catalytic activity in the cyclo-condensation reaction involving benzil, aldehyde, and NH4OAc. A series of 2,4,5-trisubstituted imidazoles were synthesized in remarkable yields using iPrOH as a green solvent.

Synthesis, biological evaluation and molecular docking study of pyrimidine linked thiazolidinedione derivatives as potential antimicrobial and antitubercular agents

The design and development of novel antimicrobial agents are highly desired to combat the emergence of medication resistance against microorganisms that cause infections. A series of new pyrimidine-linked thiazolidinedione derivatives (5a-j) were synthesized, characterized, and their antimicrobial properties assessed in the current investigation. Here, novel pyrimidine-linked thiazolidinedione compounds were designed using the molecular hybridization approach. Elemental and spectral techniques were used to determine the structures of the synthesized hybrids. The majority of compounds showed encouraging antibacterial properties. Among the active compounds, 5g, 5i, and 5j showed 1.85, 1.15, and 1.38 times the activity of streptomycin against S. aureus, respectively, with MIC values of 6.4, 10.3, and 8.6 µM. With MIC values of 10.8, 21.9, and 15.4 µM, respectively, the compounds 5g, 5i, and 5j showed 2.14, 1.05, and 1.50 times the activity of linezolid against the methicillin-resistant S. aureus (MRSA) strain. Furthermore, when compared to the reference medications, compounds 5g, 5i, and 5j demonstrated broad-range antimicrobial efficacy against all tested strains of bacteria and fungus. Out of all the compounds that were investigated, compounds 5g, 5i, and 5j showed noteworthy anti-tubercular activity. 5g is the most effective, 1.59 times more effective than reference drug isoniazid. To anticipate the binding manner, the synthesized potent compounds were subjected to molecular docking into the active binding site of MRSA and the mycobacterial membrane protein large 3 (MmpL3) protein. The compounds 5g, 5i, and 5j may eventually serve as lead compounds in the search for antimicrobial and anti-TB therapeutic agents.

Synthesis, antitubercular profile and molecular docking studies of quinazolinone-based pyridine derivatives against drug-resistant tuberculosis

The promising quinazolinone-based pyridine derivatives (4a-j) were synthesized and subsequently tested for their antimycobacterial activities against the various drug-sensitive and drug-resistant Mycobacterium tuberculosis (Mtb) strains to combat infectious diseases and address growing concerns about the devastating effects of tuberculosis (TB). Utilizing 1H NMR, 13C NMR, and mass spectra, the structural and molecular confirmation of the synthesized compounds were deciphered. With minimum inhibitory concentration (MIC) values ranging from 0.31 to 19.13 μM, the results showed that compounds 4e and 4f showed promise anti-TB action against both drug-sensitive and drug-resistant TB strains. To study the cytotoxicity of synthesized molecules, normal Vero and mouse macrophage (RAW264.7) cell lines were utilized. Remarkably, it was revealed that at the highest concentration tested, none of the newly synthesized molecules were toxic to the Vero cell line. The binding patterns of the potent compounds 4b, 4e and 4f in the active site of the mycobacterial membrane protein Large 3 (MmpL3) protein are also revealed by molecular docking studies, which has contributed to the development of a structural rationale for Mtb inhibition. The physicochemical characteristics of the compounds were then predicted using theoretical calculations. Overall, the molecular docking results, physiochemical properties, and observed antimycobacterial activity all point to compound 4e with trifluoromethyl and compound 4f with nitro moiety as potential quinazolinone linked pyridine-based MmpL3 inhibitors.Communicated by Ramaswamy H. Sarma.

Synthetic approaches to potent heterocyclic inhibitors of tuberculosis: A decade review

Tuberculosis (TB) continues to be a significant global health concern with about 1.5 million deaths annually. Despite efforts to develop more efficient vaccines, reliable diagnostics, and chemotherapeutics, tuberculosis has become a concern to world health due to HIV, the rapid growth of bacteria that are resistant to treatment, and the recently introduced COVID-19 pandemic. As is well known, advances in synthetic organic chemistry have historically enabled the production of important life-saving medications that have had a tremendous impact on patients' lives and health all over the world. Small-molecule research as a novel chemical entity for a specific disease target offers in-depth knowledge and potential therapeutic targets. In this viewpoint, we concentrated on the synthesis of a number of heterocycles reported in the previous decade and the screening of their inhibitory action against diverse strains of Mycobacterium tuberculosis. These findings offer specific details on the structure-based activity of several heterocyclic scaffolds backed by their in vitro tests as a promising class of antitubercular medicines, which will be further useful to build effective treatments to prevent this terrible illness.

Microwave-assisted N-alkylation of amines with alcohols catalyzed by MnCl2 : Anticancer, docking, and DFT studies

A new protocol for the N-alkylation of amines with alcohols for the synthesis of tertiary amines in the presence of MnCl₂ as a catalyst, under microwave conditions, is described. The advantages of this protocol include stable reaction profiles, a wide substrate variety, excellent yields, low cost, high yields, and easy workup conditions. The anticancer efficacy of all the synthesized compounds was tested in vitro against various cancer cell lines, such as MCF-7, MDA-MB-231 (human breast), HT-29, HCT 116 (colon cancer), A549 (human lung carcinoma), and Vero cells. Among the screened compounds, 3e, 3h, and 3i demonstrated potent anticancer activity, with compound 3h surpassing the reference drug cisplatin against A549, MCF7, MDA-MB-231, and HCT116 cancer cells. The introduction of an electron-withdrawing group on the phenyl ring resulted in increased anticancer activity. The most potent compounds, 3e, 3h, and 3i, were tested against VEGFR-2, HER2, and EGFR in multikinase inhibition assays, with compounds 3h and 3i showing improved potency against the HER2 kinase. The compounds formed two H-bonds with amino acids, indicating that they had a high affinity for the target HER2 kinase (PDB ID: 3RCD), according to the docking analysis. The absorption, distribution, metabolism, excretion, and toxicity properties of the optimized analogs were also assessed in vitro, enabling the discovery of promising anticancer agents. Finally, the B3LYP level was used to measure density functional theory geometry optimization and the related quantum parameters for the active compounds.

Design, synthesis and molecular docking studies of imidazole and benzimidazole linked ethionamide derivatives as inhibitors of InhA and antituberculosis agents

To explore effective antituberculosis agents, a new class of imidazoles and benzimidazoles linked ethionamide analogs were designed and synthesized. The elemental analysis, ¹H NMR, ¹³C NMR and mass spectral data were used to characterize all of the novel analogs. In vitro activity against Mycobacterium tuberculosis (Mtb) H37Rv was assessed for all of the target compounds. The hydroxy and nitrile moieties on the imidazole ring, as well as the hydroxy and methoxy groups on the benzimidazole ring connected to the ethionamide side chain, were shown to be advantageous. In our cell viability experiment against the Vero cell line, all of the compounds were non-cytotoxic even at 100 μM. To confirm the powerful analogs target identification, we investigated their in vitro inhibitory action on an M. tuberculosis InhA over-expressing (Mtb InhA-OE) strain, which yielded MICs nearly twice those of the Mtb H37Rv strain. Furthermore, the results of molecular docking confirmed the experimental findings. Additionally, the molecules were evaluated in silico for ADMET and drug similarity features. The experimental observation enables the newly generated ethionamide derivatives to be attractive candidates for the creation of newer and better anti-TB agents.

Diastereoselective Formation of Quaternary Stereocenters in Imidazole N-Oxide Cycloaddition with Fluoroalkenes

Imidazole N-oxides are attractive starting materials for the preparation of complex molecules containing an imidazole ring. Dipolar cycloaddition between 1,1-difluoroalkenes and imidazole N-oxides bearing a chiral auxiliary performed in the presence of oxygen or nitrogen nucleophiles was found to provide access to esters and amides bearing a 2-azaheteroaryl substituent at the α position of the imidazole ring as mixtures of diastereomers that, in most cases, are readily separable. This three-component reaction introduces a new tertiary or quaternary all-carbon stereocenter into the heterocyclic ring at a position originally occupied by hydrogen. Importantly, products containing a trifluoromethyl group attached to this stereocenter are readily available as well.

Discovery of a novel series of substituted quinolines acting as anticancer agents and selective EGFR blocker: Molecular docking study

A Ta₂O₅-anchored-piperidine-4-carboxylic acid (PPCA) nanoparticle has been synthesized and characterized. It was then used as a highly effective nanocatalyst for the synthesis of quinolin-2(1H)-one derivatives through CO bond functionalization. The special advantage of this heterogeneous solid catalyst is the reusability of the catalyst for up to five cycles without any noticeable reduction in product yields. In comparison, healthy reaction profiles, wide substrate scope, excellent yields and easy workup conditions are the notable highlights of this approach. All the compounds were tested for their anticancer activity against MCF-7 (human breast), HepG2 (human liver), HCT116 (human colorectal), and PC-3 (human prostate) cancer cell lines with the MTT assay. All the compounds were shown to have moderate to good inhibitory effects on tested cancer cell lines. Besides, compounds 5b, 5c and 5d showed good selectivity against epidermal growth factor receptor-tyrosine kinase (EGFR-TK). Molecular docking results showed that active compounds showed a good affinity towards EGFR kinase (PDB ID: 6V6O) by forming two hydrogen bonds with Cys-797 and Tyr-801. All the compounds were screened for computational ADMET and Lipinski analysis.

Click synthesis of 1,2,3-triazole based imidazoles: Antitubercular evaluation, molecular docking and HSA binding studies

Using Cu(I)-catalyzed cycloaddition of alkyne and azide reaction (CuAAC), a series of novel 1,2,3-triazole based imidazole derivatives (3a-e) have been synthesized. The synthesized molecules were characterized by spectroscopic techniques such as ¹H NMR, ¹³C NMR, mass and elemental analysis. Antitubercular activity (anti-TB) against Mycobacterium tuberculosis H37Rv (Mtb) and cytotoxic activity against the mammalian Vero cell line was screened for the synthesized compounds. The compounds 3d and 3e displayed potent in vitro antitubercular activity and may serve as a lead for further optimization. Besides, the experimental findings were in line with the results of molecular docking. Also, the synthesized compounds have also been analyzed for ADME properties and the experimental finding facilitates the development of new and more potent anti-TB agents in this series in the future. Using fluorescence and UV-vis absorption spectroscopy, the binding interaction of compounds (3d and 3e) with human serum albumin (HSA) was investigated. The results showed that, as a result of HSA-compound complex, the fluorescence quenching of HSA by test compounds was a static quenching process. According to Forster's theory, energy transfer efficiency is calculated.

Investigation of biological activity of 2,3-disubstituted quinazolin-4(1H)-ones against Mycobacterium tuberculosis and DNA via docking, spectroscopy and DFT studies

Docking studies, structural data of DNA binding and molecular dynamics simulations of substituted quinazolin-4(1H)-ones.

Novel 1,3,5-triazine-based pyrazole derivatives as potential antitumor agents and EFGR kinase inhibitors: synthesis, cytotoxicity, DNA binding, molecular docking and DFT studies

The development of new 1,3,5-triazine-based pyrazole derivatives as effective anticancer agents.