The Synthesis And Biological Activity Of Triazole-containing Of1,3-dioxolane

Propiconazole and Difenoconazole are a class of efficient, low toxicity,broad-spectrum and systemic fungicide, mainly for the control of wheat powderymildew, rust, root rot and leaf spot, etc. In industrial production, the crude products ofthem contain10%~15%of isomers. In this paper, we designed a new route forpreparation of high-purity Propiconazole and Difenoconazole.Propiconazole and Difenoconazole were designed and synthesized from2-arylethylene oxide by ring opening reaction with1,2,4-triazole, oxidation, andcondensation with1,2-diol. This process reduces the generation of4-substitutedtriazole isomers, and solves the problem of high content of isomers in the currenttechnological process.We also designed and synthesized a series of2-(1,2,4-triazol-1-methyl)-2-(2,2-dimethyl-2,3-dihydro-benzofuran-5-yl)-1,3-dioxolane.4-Hydroxyacetophenone wastransformed into2,2-dimethyl-5-acetyl-2,3-dihydro-benzofuran (1c) by etherification,Claisen rearrangement, cyclization reaction. Then compound1reacted with copper(II)bromide and5,5-dimethyl-1,3-dichloro-hydantoin to get2,2-dimethyl-5-acetyl-halo-2,3-dihydro-benzofuran (2a~2d). Compounds (2a~2d) react with1,2-diolketal to give2-halomethyl-2-(2,2-dimethyl-2,3-dihydro-benzofuran-5-yl)-1,3-dioxolane(3). Finally compound3was reacted with1,2,4-triazole by condensationreaction to synthesis of a series of compounds4containing a triazole,1,3-dioxolaneand benzofuran ring. The structures of the new compounds were clearly characterizedby1H NMR.The samples of2-(1,2,4-triazol-1-methyl)-2-(2,2-dimethyl-2,3-dihydro-benzofuran-5-yl)-1,3-dioxolane were tested for their fungicidal activities. The results offungicidal screening reveal that the inhibition rates of compounds4a、4f、4g、4h、4k and4l against S. sclerotiorum are more than70%at500mg/L, and the inhibitionrates of compounds4g and4h against B. graminis at25mg/L are80.0%and80.0%,respectively.