Imidazopyridine chalcones as potent anticancer agents: Synthesis, single-crystal X-ray, docking, DFT and SAR studies

New imidazopyridine-chalcone analogs were synthesized through the Claisen-Schmidt condensation reaction. The newly synthesized imidazopyridine-chalcones (S1-S12) were characterized using spectroscopic and elemental analysis. The structures of compounds S2 and S5 were confirmed by X-ray crystallography. The global chemical reactivity descriptor parameter was calculated using theoretically (DFT-B3LYP-3-211, G) estimated highest occupied molecular orbital and lowest unoccupied molecular orbital values and the results are discussed. Compounds S1-S12 were screened on A-549 (lung carcinoma epithelial cells) and MDA-MB-231 (M.D. Anderson-Metastatic Breast 231) cancer cell lines. Compounds S6 and S12 displayed exceptional antiproliferative activity against lung A-549 cancer cells with IC₅₀ values of 4.22 and 6.89 µM, respectively, compared to the standard drug doxorubicin (IC₅₀  = 3.79 μM). In the case of the MDA-MB-231 cell line, S1 and S6 exhibited exceptionally superior antiproliferative activity with IC₅₀ of 5.22 and 6.50 μM, respectively, compared to doxorubicin (IC₅₀  = 5.48 μM). S1 was found to be more active than doxorubicin. Compounds S1-S12 were tested for their cytotoxicity on human embryonic kidney 293 cells, which confirmed the nontoxic nature of the active compounds. Further molecular docking studies verified that compounds S1-S12 have a higher docking score and interacted well with the target protein. The most active compound S1 interacted well with the target protein carbonic anhydrase II in complex with pyrimidine-based inhibitor, and S6 with human Topo IIα ATPase/AMP-PNP. The results suggest that imidazopyridine-chalcone analogs may serve as new leads as anticancer agents.

Anti-tubercular activity and molecular docking studies of indolizine derivatives targeting mycobacterial InhA enzyme

A series of 1,2,3-trisubstituted indolizines (2a-2f, 3a-3d, and 4a-4c) were screened for in vitro whole-cell anti-tubercular activity against the susceptible H37Rv and multidrug-resistant (MDR) Mycobacterium tuberculosis (MTB) strains. Compounds 2b-2d, 3a-3d, and 4a-4c were active against the H37Rv-MTB strain with minimum inhibitory concentration (MIC) ranging from 4 to 32 µg/mL, whereas the indolizines 4a-4c, with ethyl ester group at the 4-position of the benzoyl ring also exhibited anti-MDR-MTB activity (MIC = 16-64 µg/mL). In silico docking study revealed the enoyl-acyl carrier protein reductase (InhA) and anthranilate phosphoribosyltransferase as potential molecular targets for the indolizines. The X-ray diffraction analysis of the compound 4b was also carried out. Further, a safety study (in silico and in vitro) demonstrated no toxicity for these compounds. Thus, the indolizines warrant further development and may represent a novel promising class of InhA inhibitors and multi-targeting agents to combat drug-sensitive and drug-resistant MTB strains.

Investigation of Antifungal Properties of Synthetic Dimethyl-4-Bromo-1-(Substituted Benzoyl) Pyrrolo[1,2-a] Quinoline-2,3-Dicarboxylates Analogues: Molecular Docking Studies and Conceptual DFT-Based Chemical Reactivity Descriptors and Pharmacokinetics Evaluation

Candida albicans, an opportunistic fungal pathogen, frequently colonizes immune-compromised patients and causes mild to severe systemic reactions. Only few antifungal drugs are currently in use for therapeutic treatment. However, evolution of a drug-resistant C. albicans fungal pathogen is of major concern in the treatment of patients, hence the clinical need for novel drug design and development. In this study, in vitro screening of novel putative pyrrolo[1,2-a]quinoline derivatives as the lead drug targets and in silico prediction of the binding potential of these lead molecules against C. albicans pathogenic proteins, such as secreted aspartic protease 3 (SAP3; 2H6T), surface protein β-glucanase (3N9K) and sterol 14-alpha demethylase (5TZ1), were carried out by molecular docking analyses. Further, biological activity-based QSAR and theoretical pharmacokinetic analysis were analyzed. Here, in vitro screening of novel analogue derivatives as drug targets against C. albicans showed inhibitory potential in the concentration of 0.4 µg for BQ-06, 07 and 08, 0.8 µg for BQ-01, 03, and 05, 1.6 µg for BQ-04 and 12.5 µg for BQ-02 in comparison to the standard antifungal drug fluconazole in the concentration of 30 µg. Further, in silico analysis of BQ-01, 03, 05 and 07 analogues docked on chimeric 2H6T, 3N9K and 5TZ1 revealed that these analogues show potential binding affinity, which is different from the therapeutic antifungal drug fluconazole. In addition, these molecules possess good drug-like properties based on the determination of conceptual Density Functional Theory (DFT)-based descriptors, QSAR and pharmacokinetics. Thus, the study offers significant insight into employing pyrrolo[1,2-a]quinoline analogues as novel antifungal agents against C. albicans that warrants further investigation.

Greener synthesis of indolizine analogues using water as a base and solvent: study for larvicidal activity against Anopheles arabiensis

Greener synthesis of a series of novel indolizine analogues have been achieved by the cyclization of aromatic cycloimmonium ylides with electron-deficient alkynes in the presence of water as the base and solvent at 80 °C. Yield of the title compounds was good and reactions performed were eco-friendly. The structures of these newly synthesized compounds have been confirmed by spectroscopic techniques such as FTIR, NMR, LC-MS, and elemental analysis. Characterized title compounds were evaluated for larvicidal activity against Anopheles arabiensis by standard WHO larvicidal assay using Temefos as standard at 4 μg/mL. Title compounds 2e, 2f, and 2g emerged as promising larvicidal agents.

1-[4-Bromo-2-(tri-fluoro-meth-oxy)phen-yl]-3-methyl-1H-1,2,4-triazole

In the title compound, C₁₀H₇BrF₃N₃O, the dihedral angle between the benzene and triazole rings is 23.17 (12)° and the C atom of the –CF₃ group deviates from its attached ring plane by 1.147 (3) Å. In the crystal, mol­ecules are linked by C—H⋯N inter­actions, generating C(7) chains running along [010].

Synthesis of Pyrimidine Incorporated Piperazine Derivatives and their Antimicrobial Activity

Thiophene substituted chalcones (1a-e) were cyclised with thiourea in presence of potassium hydroxide to get 4-substituted-6-(thiophen-2-yl)pyrimidine-2-thiols (2a-e) which were then stirred with methyl iodide to obtain 4-substituted-2-(methylsulfanyl)-6-(thiophen-2-yl)pyrimidines (3a-e). Compounds (3a-e) were refluxed with different N-methylpiperazine and N-phenylpiperazine to afford 4-substituted-2-(4-methylpiperazin-1-yl)-6-(thiophen-2-yl)pyrimidines (4a-e) and 4-substituted-2-(4-phenylpiperazin-1-yl)-6-(thiophen-2-yl)pyrimidines (5a-e). The structures of all the newly synthesised compounds 4b, 4d, 5a and 5b showed good antibacterial activity at 40μg/mlconcentration. Compounds 4a, 4d, 4e, 5c and 5e showed significant antifungal activity at 40 μg/ml concentration compared with standard drugs.

Synthesis and Pharmacological Evaluation of Azetidin-2-ones and Thiazolidin-4-ones Encompassing Benzothiazole

Various 7-chloro-6-fluoro-2-arylidenylaminobenzo(1,3)thiazole (2a-h) have been synthesized by the condensation of 7-chloro-6-fluoro-2-aminobenzo(1,3)thiazole (1) with different aromatic aldehydes. The Schiff's bases on reaction with acetyl chloride, chloroacetyl chloride and phenyl acetyl chloride yielded 1-(7-chloro-6-fluorobenzothiazol-2-yl)-3,4-substituted-aryl-azetidin-2-ones (3a-x). Similarly, cyclization of Schiff's base with thioglycolic acid furnished 3-(7-chloro-6-fluoro-benzothiazol-2-yl)-2-substituted–arylthiazolidin-4-ones (4a-h). The structures of the newly synthesized compounds have been established on the basis of their spectral data and elemental analysis. Some selected compounds were evaluated for antiinflammatory, analgesic, CNS depressant and skeletal muscle relaxant activity.

Antimicrobial evaluation of novel substituted pyrimidinopyrazoles and pyrimidinotriazoles

Some novel substituted pyramidinopyrazoles and pyrimidinotriazoles have been synthesized by using 6-anisyl-5-cyan-2-hydrazine-3-N-methyl-3, 4-dihydropyrimidine-4-one as the starting material. Structures of these compounds have been established by IR, (1)H NMR, Mass and elemental analysis data and have been evaluated for their antimicrobial activity. Significant antimi.crobial activity was observed for some members of these series.