Preparation of Fungicide Difenoconazole

The preparation of fungicide difenoconazole is studied.Difenoconazole was prepared from(2,4-dichloroacetophenone) followed by etherification,bromination,ketal reaction and nucleophilic substitution.Phenol salt formation and etherification were finished in one step pathway to give(Ⅲ) in 93.6% yield.Bromination of(Ⅲ) with bromine gave(Ⅳ) in 89.1% yield.The compound(Ⅴ) was obtained by ketal reaction of(Ⅳ) with 1,2-propylene glycol in 89.6% yield.The title compound(Ⅵ) was then prepared by nucleophilic substitution of(Ⅴ) with 1H-1,2,4-triazole in 69.0% yield.The procedure was eventually improved and the total yield reached 51.6%.