Design and synthesis of triazole sulfonamide inhibitors of bc1 complex

Currently, triazole sulfonamide fungicide could be used to effectively control cucumber downy mildew (CDM), caused by Pseudoperonospora cubensis . In this study, a series of triazole sulfonamide derivatives containing diphenyl ether (DE) fragment were designed and synthesized. All target compounds were evaluated for their fungicidal activity against four oomycete diseases. Compound 10b showed the best activity against CDM with 40 % control efficacy at 0.78 mg/L, which was the same as amisulbrom. Meanwhile, compounds 10d and 10h showed good inhibitory activity against Peronophythora litchii and compounds 10e , 10f , 10l and 10q showed good inhibitory activity against Phytophthora infestans . The results of computational chemistry showed that compound 10b had the same binding mode as amisulbrom and formed hydrogen bonds with the residues Gln9, His189 and Ash217. Compound 10b could be further investigated as a potential fungicide candidate. This study also provides a useful optimization strategy for the design of novel fungicides against CDM. • A series of novel triazole sulfonamide derivatives were designed and synthesized. • Compound 10b showed the best activity against CDM with 40 % control efficacy at 0.78 mg/L. • Compound 10b with favorable control efficacy acts as a promising fungicide candidate for bc 1 complex.