This compound can be obtained by two related ways: 1) The reaction of alpha-bromo-2-chlorostyrene (I) with magnesium gives the corresponding magnesiane (II), which is condensed with alpha,4-dichloroacetophenone (III) yielding 3-(2-chlorophenyl-2-(4-chlorophenyl)-1,2-epoxy-3-butene (IV). Finally, this compound is treated with potassium 1,2,4-triazole (V). 2) The reaction of 1-(2-chlorophenyl)-2-(4-chlorophenyl)-2,3-epoxy-1-propane (VI) with methyltriphenylphosphonium bromide and n-butyllithium gives epoxide (IV), already obtained.
The intermediate epoxide (IV) was synthesized by two different procedures: 1) The Grignard reagent (II), prepared from 1-bromo-2'-chlorostyrene (I) and Mg, was condensed with 2-chloro-2',4'-difluoroacetophenone (III) to afford epoxide (IV). 2) Alternatively, Wittig reaction of epoxyketone (V) with methylenetriphenylphosphorane provided the target intermediate (IV). The title compound was then obtained by epoxide opening of (IV) with potassium triazole (VI) in DMF at 60 C, and was isolated as the methanesulfonate salt.