Design, synthesis and antifungal activity of novel 1,3,4‐Oxadiazole derivatives against <scp> <i>Botrytis cinerea</i> </scp>

Abstract BACKGROUND Botrytis cinerea , a highly destructive fungal pathogen with a broad host range, inflicts massive pre‐ and post‐harvest losses on crops like tomatoes and blueberries, endangering global agricultural sustainability and food security. Escalating pesticide resistance reduces the efficacy of conventional fungicides, creating an urgent need for novel, efficient, low‐toxicity antifungal agents. 1,3,4‐oxadiazole derivatives possess diverse bioactivities, making them ideal candidates for development. RESULTS Thirty novel 1,3,4‐oxadiazole derivatives were rationally designed via scaffold hopping and active substructure splicing. In vitro and in vivo assays showed compound R30 had the best antifungal activity, targeting lanosterol 14α‐demethylase to inhibit ergosterol synthesis, disrupting cell membranes, and inducing hyphal deformation. It exhibits favorable ADME properties, low toxicity to HaCaT/HSF cells (IC 50 > 200 μM). CONCLUSION Compound R30 is a promising lead for efficient, low‐toxicity antifungal pesticides against B. cinerea . This study validates the adopted design strategy, enriches the structural diversity of ergosterol synthesis inhibitors, and provides valuable insights for sustainable control of fungal diseases and pesticide resistance. © 2026 Society of Chemical Industry.