Synthesis of new pyrazole-triazole hybrids by click reaction using a green solvent and evaluation of their antitubercular and antibacterial activity

Design and Synthesis of Novel Celecoxib Analogues with Potential Cytotoxic and Pro-apoptotic Activity Against Breast Cancer Cell Line MCF-7

BACKGROUND

Breast cancer is currently the leading cause of worldwide cancer incidence exceeding lung cancer. In addition, breast cancer accounts for 1 in 4 cancer cases and 1 in 6 cancer deaths among women. Cytotoxic chemotherapy is still the main therapeutic approach for patients with metastatic breast cancer.

OBJECTIVE

To synthesize a series of novel celecoxib analogues to evaluate their anticancer activity against MCF-7 cell line.

METHOD

Our design of target compounds was based on preserving the pyrazole moiety of celecoxib attached to two phenyl rings, one of them having polar hydrogen bonding group (sulfonamide or methoxy group). The methyl group of the second phenyl ring was replaced with chlorine or bromine atom. Finally, the trifluoromethyl group was replaced with arylidene hydrazine-1-carbonyl moiety, which is substituted either with fluoro or methoxy group, offering various electronic and lipophilic environments. These modifications were carried out to investigate their effects on the anti-proliferative activity of the newly synthesized celecoxib analogues and to provide a valuable structure activity relationship.

RESULTS

Four compounds namely (4e-h) exhibited significant antitumor activity. Compounds 4e, 4f and 4h showed 1.2-2 folds more potent anticancer activity than celecoxib. Celecoxib analogue 4f showed the most potent anti-proliferative activity. Its anti-proliferative activity seems to associate well with its ability to inhibit BCL-2. Moreover, activation of damage response pathway of the DNA leads to cell cycle arrest at G2/M phase, accumulation of cells in pre-G1 phase, indicating that cell death proceeds through an apoptotic mechanism. Compound 4f exhibited potent pro-apoptotic effect via induction of the intrinsic mitochondrial pathway of apoptosis. This mechanistic pathway was proved by a significant increase in the expression of the tumor suppressor gene p53, elevation in Bax/BCL-2 ratio and a significant increase in the level of active caspase-7. Furthermore, compound 4f showed moderate COX-2 inhibitory activity.

CONCLUSION

Celecoxib analogue 4f is a promising multi-targeted lead for the design and synthesis of potent anticancer agents.

Triazole-containing hybrids with anti-Mycobacterium tuberculosis potential - Part I: 1,2,3-Triazole

Tuberculosis regimens currently applied in clinical practice require months of multidrug therapy, which imposes a major challenge of patient compliance and drug resistance development. Moreover, because of the increasing emergence of hard-to-treat tuberculosis, this disease continues to be a significant threat to the human population. 1,2,3-triazole as a privileged structure has been widely used as an effective template for drug discovery, and 1,2,3-triazole-containing hybrids that can simultaneously act on dual or multiple targets in Mycobacterium tuberculosis have the potential to circumvent drug resistance, enhance efficacy, reduce side effects and improve pharmacokinetic as well as pharmacodynamic profiles. Thus, 1,2,3-triazole-containing hybrids are useful scaffolds for the development of antitubercular agents. This review aims to highlight recent advances of 1,2,3-triazole-containing hybrids with potential activity against various forms of M. tuberculosis, covering articles published between 2015 and 2020. The structure-activity relationship and the mechanism of action are also discussed to facilitate further rational design of more effective drug candidates.

Nanocrystalline ZnO: A Competent and Reusable Catalyst for the Preparation of Pharmacology Relevant Heterocycles in the Aqueous Medium

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Nanoparticle catalyzed synthesis is a green and convenient method to achieve most of the chemical transformations in water or other green solvents. Nanoparticle ensures an easy isolation process of catalyst as well as products from the reaction mixture avoiding the hectic work up procedure. Zinc oxide is a biocompatible, environmentally benign and economically viable nanocatalyst with effectivity comparable to the other metal nanocatalyst employed in several reaction strategies. This review mainly focuses on the recent applications of zinc oxide in the synthesis of biologically important heterocyclic molecules under sustainable reaction conditions.

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Application of zinc oxide in organic synthesis: Considering the achievable advantages of this nanocatalyst, presently several research groups are paying attention in anchoring zincoxide or its modified structure in several types of organic conversions e.g. multicomponent reactions, ligand-free coupling reactions, cycloaddition reaction, etc. The advantages and limitations of this nanocatalyst are also demonstrated. The present study aims to highlight the recent multifaceted applications of ZnO towards the synthesis of diverse heterocyclic motifs. Being a promising biocompatible nanoparticle, this catalyst has an important contribution in the fields of synthetic chemistry and medicinal chemistry.

Development of pyrazole and spiropyrazoline analogs as multifunctional agents for treatment of Alzheimer's disease

Cholinergic hypothesis of Alzheimer's disease has been advocated as an essential tool in the last couple of decades for the drug development. Here in, we report de novo fragment growing strategy for the design of novel 3,5-diarylpyrazoles and hit optimization of spiropyrazoline derivatives as acetyl cholinesterase inhibitors. Both type of scaffolds numbering forty compounds were synthesized and evaluated for their potencies against AChE, BuChE and PAMPA. Introduction of lipophilic cyclohexane ring in 3,5-diarylpyrazole analogs led to spiropyrazoline derivatives, which facilitated and improved the potencies. Compound 44 (AChE = 1.937 ± 0.066 µM; BuChE = 1.166 ± 0.088 µM; hAChE = 1.758 ± 0.095 µM; P_e = 9.491 ± 0.34 × 10^-6 cm s¹) showed positive results, which on further optimization led to the development of compound 67 (AChE = 0.464 ± 0.166 µM; BuChE = 0.754 ± 0.121 µM; hAChE = 0.472 ± 0.042 µM; P_e = 13.92 ± 0.022 × 10^-6 cm s¹). Compounds 44 and 67 produced significant displacement of propidium iodide from the peripheral anionic site (PAS) of AChE. They were found to be safer to MC65 cells and decreased metal induced Aβ_1-42 aggregation. Further, in-vivo behavioral studies, on scopolamine induced amnesia model, the compounds resulted in better percentage spontaneous alternation scores and were safe, had no influence on locomotion in tested animal groups at dose of 3 mg/kg. Early pharmacokinetic assessment of optimized hit molecules was supportive for further drug development.

Efficient synthesis of novel pyrazole-linked 1,2,4-triazolidine-3-thiones using bismuth on zirconium oxide as a recyclable catalyst in aqueous medium

The Bi₂O₃ loading on ZrO₂ as heterogeneous catalyst was established as an extremely efficient catalyst for the synthesis of a series of novel 5-(1-(2,4-dinitrophenyl)-3-substituted-phenyl-1H-pyrazol-4-yl)-1,2,4-triazolidine-3-thione derivatives (3a-o) with high yields (90-96%) by reaction of 1-(2,4-dinitrophenyl)-3-substituted-phenyl-1H-pyrazole-4-carbaldehydes and thiosemicarbazide using water as a greener solvent at 80 °C within 30-45 min. Materials with different percentages of Bi₂O₃ on ZrO₂ were prepared by simple wet impregnation method. The synthesized material has been characterized by various techniques (XRD, TEM, SEM, BET). 2.5% Bi₂O₃/ZrO₂ proved superior catalyst. The Bi₂O₃/ZrO₂ catalyst is easily recoverable and reused up to sixth run with no loss of activity. Excellent yields, short reaction time, avoidance of hazardous solvents, and no need for chromatographic purifications are the proven advantages.

Sequential one-pot three-step synthesis of polysubstituted 4-(5-(trifluoromethyl)-1H-pyrazol-4-yl)-1H-1,2,3-triazole systems

Sequential one-pot, three-step synthesis of polysubstituted 4-(5-(trifluoromethyl)-1H-pyrazol-4-yl)-1H-1,2,3-triazoles.

K. N, Kayarmar R, S. K. P, R MS. Design, synthesis and characterization of new 1,2,3-triazolyl pyrazole derivatives as potential antimicrobial agents via a Vilsmeier–Haack reaction approach

A new series of 1,2,3-triazolyl pyrazole derivatives were synthesisedviaa Vilsmeier–Haack reaction approach and screened for theirin vitroanti-bacterial, anti-fungal and anti-oxidant activities.