Design, synthesis, and antifungal activity study of
N
‐substituted phenyl pyrazole containing amides
Wei Zhang, Renwu Yu, Yi Wang, Shisen Xing, Xiaoyang Li, Fei Cao, Longfei Li, Wan Li Abstract
BACKGROUND
Plant pathogenic fungi pose a serious threat to global crop productivity. Succinate dehydrogenase inhibitors (SDHIs) exhibit superior curative activity, longer residual efficacy, and lower mammalian toxicity compared to other fungicides, making them the most studied fungicide class.
RESULTS
A series of N‐substituted phenyl pyrazole amide derivatives ( D1 – D32 ) were designed by nitrogen substitution and amide linker extension to enhance their antifungal activity and broad‐spectrum properties. As a result, the crystal structures of compounds D6 and D19 were researched, and compound D19 showed strong activity against Rhizoctonia cerealis (half‐maximal effective concentration (EC 50 ) = 4.40 μg mL −1 ), with protective and curative effects of 83.0% and 72.8% at 100 μg mL −1 , respectively. Mechanistic studies revealed that compound D19 could inhibit the activity of succinate dehydrogenase (SDH), disrupting the tricarboxylic acid (TCA) cycle. Molecular docking and molecular dynamics simulations confirmed the binding mode of compound D19 with SDH, and toxicity assays revealed a favorable safety profile of compound D19 .
CONCLUSION
Novel N‐substituted phenyl pyrazole amide derivatives with strong antifungal activity and safety profile can be used as a lead compound for the new type of SDHI fungicide. © 2026 Society of Chemical Industry.