Discovery of Pyrazine-Carboxamide-Diphenyl-Ethers as Novel Succinate Dehydrogenase Inhibitors via Fragment Recombination
Hua Li, Mengqi Gao, Yan Chen, Yuxia Wang, Xiao‐Lei Zhu, Guang‐Fu Yang
Abstract
The discovery of novel succinate dehydrogenase inhibitors (SDHIs) has attracted great attention worldwide. Herein, a fragment recombination strategy was proposed to design new SDHIs by understanding the ligand–receptor interaction mechanism of SDHIs. Three fragments, pyrazine from pyraziflumid, diphenyl-ether from flubeneteram, and a prolonged amide linker from pydiflumetofen and fluopyram, were identified and recombined to produce a pyrazine-carboxamide-diphenyl-ether scaffold as a new SDHI. After substituent optimization, compound 6y was successfully identified with good inhibitory activity against porcine SDH, which was about 2-fold more potent than pyraziflumid. Furthermore, compound 6y exhibited 95% and 80% inhibitory rates against soybean gray mold and wheat powdery mildew at a dosage of 100 mg/L in vivo assay, respectively. The results of the present work showed that the pyrazine-carboxamide-diphenyl-ether scaffold could be used as a new starting point for the discovery of new SDHIs.