Synthesis and Fungicidal Activity of the Cycloproply Derris Dihydrazone Derivatives

Abstract

A novel series of cycloproply derris dihydrazone derivatives 3a~3p were designed and synthesized by reacting substituted aldehydes/ketones with intermediate (2R)-5-[(5',6'-dimethoxy-1',1'a,2',7'b-tetrahydrocyclopro-pa[c]chromen-7'byl)(hydrazono)methyl]-2-(prop-1"-en-2"-yl)-2,3-dihydrobenzofuran-4-ol (2), which was synthesized via the reactions of the rotenone, dimethyloxosulphonium methylide and hydrazine hydrate. Their structures were characterized by H NMR and LRMS. The results of bioassay indicated that the title compounds exhibited potent fungicidal activity against Rhizoctonia solani, Sclerotonia sclerotiorum and Blumeria graminis. Compounds 3d and 3o showed 55.1% and 55.5% control rates against Rhizoctonia solani at 500 mg/L, respectively, compounds 3a, 3c, 3e, 3h and 3k showed 76.8%, 87.0%, 70.6%, 72.5% and 65.2% inhibition rates against Sclerotonia sclerotiorum at 25 mg/L, respectively, and compounds 3a, 3c, 3g, 3i and 3l showed 80.0%~90.0% control rate against Blumeria graminis at 500 mg/L.