Development of novel indole-linked pyrazoles as anticonvulsant agents: A molecular hybridization approach.

A series of 3-{2-[1-acetyl-5-(substitutedphenyl)-4,5-dihydropyrazol-3-yl]hydrazinylidene}-1,3-dihydro-2H-indol-2-ones 24-43 was synthesized using an appropriate synthetic route and evaluated experimentally by the maximal electroshock test. These compounds were evaluated for antidepressant and antianxiety activities. The most active compound, 3-{2-[1-acetyl-5-(4-chlorophenyl)-4,5-dihydropyrazol-3-yl]hydrazinylidene}-1,3-dihydro-2H-indol-2-one 25, exhibited an ED ₅₀ of 13.19 mmol/kg, a TD ₅₀ of 43.49 mmol/kg, and a high protective index of 3.29, compared with the standard drug diazepam. To get insights into the intermolecular interactions, molecular docking studies were performed at the active site of the GABA _A receptor and the MAO-A enzyme. Molecular docking studies are also in agreement with the pharmacological evaluation with potent compounds, exhibiting docking scores of -1.5180 and 0.7458 for the GABA _A receptor and MAO-A, respectively. The 3D-QSAR analysis was carried out by Vlife MDS engine 4.3.1, and a statistically reliable model with good predictive power (r ²  = 0.7523, q ²  = 0.3773) was achieved. The 3D-QSAR plots gave insights into the structure-activity relationship of these compounds, which may aid in the design of potent benzopyrrole derivatives as anticonvulsant agents. So, our research can make a great impact on those medicinal chemists who work on the development of anticonvulsant agents.
(© 2020 Deutsche Pharmazeutische Gesellschaft.)