Green Synthesis, In Silico Molecular Docking, and Evaluation of Pyrazole Derivatives for Their Antifungal and Antinemic Activity

Abstract

A series of 25 pyrazole derivatives was synthesized via ultrasonication‐assisted cyclization of chalcones with phenylhydrazine and characterized using 1H NMR, 13C NMR, and LC‐HRMS. Biological evaluation revealed that P‐25 [5‐(4‐fluorophenyl)‐1,3‐diphenyl‐1H‐pyrazole] exhibited the highest antifungal activity against Rhizoctonia solani (ED50 = 5.56 µg mL−1), approaching the efficacy of positive control hexaconazole 5% SC (ED50 = 3.67 µg mL−1). While P‐6 [5‐(3‐nitrophenyl)‐1,3‐diphenyl‐1H‐pyrazole] was most effective against Fusarium oxysporum (ED50 = 301.5 µg mL−1). In nematicidal assays, P‐21 [3‐(4‐ethoxyphenyl)‐5‐(4‐nitrophenyl)‐1‐phenyl‐1H‐pyrazole] showed the greatest activity against Meloidogyne incognita (LC50 = 31.25 µg mL−1, 24 h) although less potent than fluopyram 34.48% SC (Velum Prime) (LC50 = 3.46 µg mL−1). Molecular docking studies targeting succinate dehydrogenase (SDH) supported the experimental results, with P‐6, P‐25, and P‐21 exhibiting the strongest binding affinities against SDH of F. oxysporum (−8.3 kcal mol−1), R. solani (−8.3 kcal mol−1), and M. incognita (−7.7 kcal mol−1), respectively.