1. Novel Pyrazole Acyl(thio)urea Derivatives Containing a Biphenyl Scaffold as Potential Succinate Dehydrogenase Inhibitors: Design, Synthesis, Fungicidal Activity, and SAR.
- Author
-
Sun NB, Min LJ, Sun XP, Zhai ZW, Bajsa-Hirschel J, Wei ZC, Hua XW, Cantrell CL, Xu H, Duke SO, and Liu XH
- Subjects
- Urea, Molecular Docking Simulation, Structure-Activity Relationship, Pyrazoles chemistry, Antifungal Agents pharmacology, Succinate Dehydrogenase, Fungicides, Industrial chemistry, Biphenyl Compounds
- Abstract
As part of a program to discover novel succinate dehydrogenase inhibitor fungicides, a series of new pyrazole acyl(thio)urea compounds containing a diphenyl motif were designed and synthesized. Their structures were confirmed by
1 H NMR, HRMS, and single X-ray crystal diffraction analysis. Most of these compounds possessed excellent activity against 10 fungal plant pathogens at 50 μg mL-1 , especially against Rhizoctonia solani, Alternaria solani , Sclerotinia sclerotiorum , Botrytis cinerea , and Cercospora arachidicola . Interestingly, compounds 3-(difluoromethyl)-1-methyl- N -((3',4',5'-trifluoro-[1,1'-biphenyl]-2-yl)carbamoyl)-1 H -pyrazole-4-carboxamide ( 9b , EC50 = 0.97 ± 0.18 μg mL-1 ), 1,3-dimethyl- N -((3',4',5'-trifluoro-[1,1'-biphenyl]-2-yl)carbamoyl)-1 H -pyrazole-4-carboxamide ( 9a , EC50 = 2.63 ± 0.41 μg mL-1 ), and N -((4'-chloro-[1,1'-biphenyl]-2-yl)carbamoyl)-1,3-dimethyl-1 H -pyrazole-4-carboxamide ( 9g , EC50 = 1.31 ± 0.15 μg mL-1 ) exhibited activities against S. sclerotiorum that were better than the commercial fungicide bixafen (EC50 = 9.15 ± 0.05 μg mL-1 ) and similar to the positive control fluxapyroxad (EC50 = 0.71 ± 0.11 μg mL-1 ). These compounds were not significantly phytotoxic to monocotyledonous and dicotyledonous plants. Structure-activity relationships (SAR) are discussed by substituent effects/molecular docking, and density functional theory analysis indicated that these compounds are succinate dehydrogenase inhibitors.- Published
- 2024
- Full Text
- View/download PDF