Synthesis and Fungicidal Activity of N-(2,4,5-trichlorophenyl)-2-Oxo-and 2-Hydroxycycloalkylsulfonamides

A series of N-(2,4,5-trichlorophenyl)-2-Oxo- and 2-Hydroxycycloalkyl-sulfonamides (series II and III) were designed and synthesized based on the leading compound chesulfamide (code name: CAUWL-2004-L-13). Their structures were confirmed by H-1 NMR, IR and elemental analysis. Compounds II and III showed excellent activities against the Botrytis cinerea both in vitro and in vivo. Mycelia growth and conidial germination assays exhibited that EC50 of compound IId were 0.64 mu g mL(-1) and 0.34 mu g mL(-1) respectively. For in vivo control of B. cinerea in cucumber seedlings, compounds IIb and IId showed better control effect than the commercial fungicides procymidone and pyrimethanil. In addition, these new compounds had broader fungicidal spectra than chlorothalonil. The fungicidal activity was affected obviously by the size of cycloalkane. All the compounds with six-, seven-, and eight-membered ring showed high fungicidal activities.