Discovery of Novel Pyrazole Carboxylate Derivatives Containing Thiazole as Potential Fungicides.

Inspired by commercially established fluxapyroxad as the lead compound of novel efficient antifungal ingredients, novel pyrazole carboxylate derivatives containing a flexible thiazole backbone were successfully designed, synthesized, and detected for their and biological activities against eight agricultural fungi. The antifungal bioassay results showed that compound revealed excellent bioactivities against and , with median effective concentrations (EC) of 0.40 and 3.54 mg/L, respectively. Compound revealed remarkable antifungal activity against , with an EC value of 0.32 mg/L. For fungicide control against and , compounds and at 25 mg/L, respectively, displayed prominent efficacy on cherry tomatoes and apple branches. Molecular docking results demonstrated that compound could form an interaction with several crucial residues of succinate dehydrogenase (SDH), and the enzyme assay indicated that the target compound displayed an inhibitory effect toward SDH, with an IC value of 82.26 μM. The experimental results indicated that phenyl pyrazole carboxylate derivatives displayed a weak antifungal property and low activity compared to the other title substituent pyrazole carboxylate derivatives. Compounds , , and are promising antifungal candidates worthy of further fungicide development due to their prominent effectiveness.