Design, synthesis and fungicidal activity of novel 2-substituted aminocycloalkylsulfonamides

Abstract

A series of novel 2-substituted aminocycloalkylsulfonamides were designed and synthesized by highly selective N-alkylation reaction, whose structures were characterized by ¹H NMR, ¹³C NMR and HRMS. Among them, the configuration of compounds III12 and III20 were confirmed by X-ray single crystal diffraction. Bioassays demonstrated that the title compounds had considerable effects on different strains of Botrytis cinerea and Pyricularia grisea. Comparing with positive control procymidone (EC₅₀=10.31mg/L), compounds III28, III29, III30 and III31 showed excellent fungicidal activity against a strain of B. cinerea (CY-09), with EC₅₀ values of 3.17, 3.04, 2.54 and 1.99mg/L respectively. Their in vivo fungicidal activities were also better than the positive controls cyprodinil, procymidone, boscalid and carbendazim in pot experiments. Moreover, the fungicidal activity of III28 (EC₅₀=4.62mg/L) against P. grisea was also better than that of the positive control isoprothiolane (EC₅₀=6.11mg/L). Compound III28 would be great promise as a hit compound for further study based on the structure-activity relationship.

Keywords: 2-Aminocycloalkylsulfonamides; Botrytis cinerea; Fungicidal activity; Structure-activity relationship.