Synthesis, Antimicrobial Activity, and Molecular Docking of Benzoic Hydrazide or Amide Derivatives Containing a 1,2,3‐Triazole Group as Potential SDH Inhibitors

Abstract

Main observation and conclusionThe present study was carried out in an attempt to synthesize a new class of antimicrobial agents containing a 1,2,3‐triazole motif formed by classical copper catalyzed click chemistry. Antifungal bioassay results showed that five compounds 5a, 5e, 5h, 5j, and 5k possessed a remarkable growth inhibitory activity against Botryosphaeria dothidea, Rhizoctonia solani and Gibberella zeae with EC50 values within 10.0—0.306 μg/mL. The in vitro efficacy was better than those of the commercial agrochemicals Azoxystrobin, Boscalid, and Fluxapyroxad. In vivo trials showed that compound 5l was effective for the control of rice sheath blight and wheat scab with the effects of 75% and 95%, respectively. Antifungal mechanism studies suggested that target compounds were potential succinate dehydrogenase inhibitors (SDHIs), which were proposed by the agreeable molecular docking study and restrained SDH activity (IC50 = 3.95 μg/mL, 5l). Interestingly, compounds 5r and 5s displayed good antibacterial activity against phytopathogens. In vivo screening of 5r and 5s against rice bacterial blight afforded a superior control effect (up to 51%) than those of commercial agents Bismerthiazol and Thiodiazole copper. The current studies could support some title compounds to be the lead compounds for exploring highly bioactive antimicrobial substrates, particularly the potential SDHIs.