Mohammad Shahar Yar

Recent Advances and Future Perspectives of Triazole Analogs as Promising Antiviral Agents

Emergence of severe viral infections in recent years and limited availability of antiviral chemotherapeutic agents for prevention and treatment of these infections are among the most common causes of human illness and death. Therefore, there is an urgent need to develop antiviral drugs that have a potentially critical role in the prevention and treatment of various fatal and debilitating viral infections. Triazole derivatives occupy a pivotal position in modern medicinal chemistry and several have found applications as medicines. A large volume of research has been carried out on triazole and their derivatives for antiviral activity and pharmacological importance of this scaffold has been well established. This review is primarily addressed to description of the recent advances in the synthesis and evaluation of triazole derivatives as antiviral agents which may facilitate the development of more potent and effective antiviral agents.

Thiazolidine-2,4-diones derivatives as PPAR-γ agonists: synthesis, molecular docking, in vitro and in vivo antidiabetic activity with hepatotoxicity risk evaluation and effect on PPAR-γ gene expression.

A library of conjugates of chromones and 2,4-thiazolidinedione has been synthesized by Knoevenagel condensation followed by reduction using hydrogen gas and Pd/C as a catalyst. Compounds 5c and 5e were most effective in lowering the blood glucose level comparable to standard drug pioglitazone. Compound 5e exhibited potent PPAR-γ transactivation of 48.72% in comparison to pioglitazone (62.48%). All the molecules showed good glide score against the PPAR-γ target in molecular docking study. PPAR-γ gene expression was significantly increased by compound 5e (2.56-fold) in comparison to standard drug pioglitazone. Compounds 5e and 5c did not cause any damage to the liver and may be considered as promising candidates for the development of new antidiabetic agents.

Design, synthesis, in silico molecular docking and biological evaluation of novel oxadiazole based thiazolidine-2,4-diones bis-heterocycles as PPAR-γ agonists.

A library of novel 1,3,4-oxadiazole and 2-4-thiazolidinedione based bis-heterocycles 7 (a-r) has been synthesized which exhibited significant PPAR-γ transactivation and blood glucose lowering effect comparable with the standard drugs Pioglitazone and Rosiglitazone. Compounds 7m and 7r did not cause body weight gain and were found to be free from hepatotoxic and cardiotoxic side effects. Compounds 7m and 7r increased PPAR-γ gene expression by 2.10 and 2.00 folds, respectively in comparison to the standard drugs Pioglitazone (1.5 fold) and Rosiglitazone (1.0 fold). Therefore the compounds 7m and 7r may be considered as potential candidates for development of new antidiabetic agents.

Synthesis and antitubercular activity of substituted novel pyrazoline derivatives

A series of 2-2-methoxy-4-[5-(substituted phenyl)1-(4-pyridylcarbonyl)-4,5-dihydro-1H-3-pyrazolyl] phenoxyacetic acid were synthesized by the reaction between isoniazid (INH) and chalcones, and were tested for their antimycobacterial activity in vitro against Mycobacterium tuberculosis H37Rv and INH resistant M. tuberculosis using BACTEC-460 radiometric system and agar dilution method. Among the synthesized compounds, Compounds II 2-4-[5-(4-hydroxyphenyl)-1-(4-pyridylcarbonyl)-4,5-ihydro-1H-3-pyrazolyl]-2-methoxy phenoxy acetic acid was found to be most active agent against M. tuberculosis H37Rv (MTB) and INH resistant M. tuberculosis (INHR-MTB), with minimum inhibitory concentration of 0.12 µM, when compared to INH 5.6-fold more active against MTB and 78-fold more active against INHR-MTB, respectively.

Design, synthesis and evaluation of novel 5,6-dimethoxy-1-oxo-2,3-dihydro-1H-2-indenyl-3,4-substituted phenyl methanone analogues.

In present investigation, a series of substituted phenyl-5,6-dimethoxy-1-oxo-2,3-dihydro-1H-2-indenylmethanone analogues were synthesized and were tested for their potential for treating AD disease. All the newly synthesized compounds were showing moderate to high AChE inhibitory activities, with compound 5,6-dimethoxy-1-oxo-2,3-dihydro-1H-2-indenyl-3,4,5-trimethoxyphenylmethanone (5f) produced significant activities with 2.7+/-0.01 micromol/L.

Design, Synthesis, and Biological Evaluation of Thiazolidine-2,4-dione Conjugates as PPAR-γ Agonists.

A library of synthesized conjugates of phenoxy acetic acid and thiazolidinedione 5a–m showed potent peroxisome proliferator activated receptor‐γ (PPAR‐γ) transactivation as well as significant blood glucose lowering effect comparable to the standard drugs pioglitazone and rosiglitazone. Most of the compounds showed higher docking scores than the standard drug rosiglitazone in the molecular docking study. Compounds 5l and 5m exhibited PPAR‐γ transactivation of 54.21 and 55.41%, respectively, in comparison to the standard drugs pioglitazone and rosiglitazone, which showed 65.94 and 82.21% activation, respectively. Compounds 5l and 5m significantly lowered the blood glucose level of STZ‐induced diabetic rats. Compounds 5l and 5m lowered the AST, ALT, and ALP levels more than the standard drug pioglitazone. PPAR‐γ gene expression was significantly increased by compound 5m (2.00‐fold) in comparison to the standard drugs pioglitazone (1.5‐fold) and rosiglitazone (1.0‐fold). Compounds 5l and 5m did not cause any damage to the liver and could be considered as promising candidates for the development of new antidiabetic agents.

Design, Synthesis, and Biological Evaluation of Novel Quinazoline Clubbed Thiazoline Derivatives

A novel series of quinazoline clubbed thiazoline derivatives was rationally designed and synthesized. The newly synthesized compounds were evaluated for in vitro dipeptidyl peptidase IV (DPP‐4) inhibitory activity. Compounds that showed good to moderate activity were compared using linagliptin as standard. Compound 4x (IC50 = 1.12 nM) exhibited the most promising results. The special chemical feature of compound 4x also imparts good inhibition selectivity for DPP‐4 over DPP‐8/9. Moreover, docking of compound 4x into the active site of DPP‐4 illustrates its possible binding interactions.

Synthesis and Evaluation of Benzimidazole Derivatives as Selective COX-2 Inhibitors

A new series of 1-{(5-substituted-alkyl/aryl-1,3,4-oxadiazol-2-yl)methyl}-2-(piperidin-1-ylmethyl)-1Hbenzimidazoles (5a-5r) was synthesized and screened for their inhibitory activity against COX (1 and 2). In vivo antiinflammatory activity of potent compounds was done by carrageenan-induced rat paw edema model. In vitro anticancer activity of synthesized compounds was also performed at the National Cancer Institute (NCI) against NCI 60 cell lines panel. Out of the 18 compounds screened, 5h, 5i, 5j and 5l were found to be potent COX-2 inhibitors in the range of IC50 0.06-0.81 μM. In vivo anti-inflammatory screening results revealed that the compounds 5h and 5j manifested profound percent protection of 72.8 and 75.0%, respectively. Compound 5f exhibited moderate cytotoxicity with 58.79% growth inhibition against SNB-75 (CNS Cancer) cell lines and moderate activity against COX-2 (IC50 = 8.0 μM).

Antitubercular activity of novel substituted 4, 5-dihydro-1H-1- pyrazolylmethanethiones

A series of, anilino-5- (substituted) phenyl -3-(4-hydroxy-3-methylphenyl)-4,5-dihydro-1H-1-pyrazolylmethanethione and 2-chloroanilino-5- (substituted) phenyl -3-(4-hydroxy-3-methylphenyl)-4,5-dihydro-1H-1-pyrazolylmethanethione were synthesized by the reaction between hydrazine hydrate and the chalcones (3a–k) followed by condensation with the appropriate aryl isothiocyanate which yielded the N-substituted pyrazoline derivatives. These were tested for their in-vitro anti-mycobacterial activity against INH resistant Mycobacterium tuberculosis (INHR MTB) using the BACTEC 460 radiometric system. Compound 2-chloroanilino-5-(2,6-dichlorophenyl)-3-(4-hydroxy-3-methylphenyl)-4,5-dihydro-1H-1-pyrazolylmethanethione (6i) was found to be most active agent with a minimum inhibitory concentration of 0.96μg/mL.

Design, Synthesis, and Biological Evaluation of 6-(2-Amino-substituted phenyl)-4-(substituted phenyl)-1,2,4-triazine-3,5(2H,4H)-dione Derivatives as Anticonvulsant Agents.

As per structural requirement essential for anticonvulsant activity, a series of new 6‐(2‐amino‐substituted phenyl)‐4‐(substituted phenyl)‐1,2,4‐triazine‐3,5‐dione derivatives were designed and synthesized. All the synthesized title derivatives were assessed for in vivo anticonvulsant screening by the two most employed standard animal seizure models, maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ)‐induced seizures, along with minimal motor impairment screening by rotarod test. Among all the synthesized compounds, the compound 4r showed excellent anticonvulsant activity with neither signs of neurotoxicity in the minimal motor impairment test nor signs of hepatotoxicity in the serum enzyme activity assay. The in silico studies of these title compounds were carried out for estimation of a pharmacophore pattern and the prediction of pharmacokinetic properties. To know the exact mechanism of our title compounds, a molecular docking study was carried out on the homology model of sodium ion (Na+) channel and GABAA receptors. The results of the docking study as well as the in vitro study on both the receptors showed that our target compounds best act through the GABAA receptor rather than the Na+ channel receptors. Additionally, GABA enzyme estimation was performed for further confirmation of the mechanism involved in its anticonvulsant activity. Conclusively, the compound 4r presents a novel scaffold in the search for safer and efficient anticonvulsants having neuroprotective as well as GABAergic effects.