Patent ID: 6194584
Filing Date: 2001-02-27
Classification: C07D

Abstract:
Process for the preparation of a compound of formula VII ##STR9##wherein R.sub.1 is chlorine, fluorine or trifluoromethyl;R.sub.2 is hydrogen, chlorine, fluorine or trifluoromethyl;R.sub.3 is C.sub.1-4 alkyl; characterized in that an olefin of formula ##STR10##wherein R.sub.1 and R.sub.2 are as defined above, and R is hydrogen or a protecting group of the hydroxy moiety, is epoxidized to give the oxirane of III ##STR11##wherein R, R.sub.1 and R.sub.2 are as defined above, which, treated With (C.sub.1-4)alkyl-magnesium halide in the presence of copper(I) iodide gives a triol of formula IV ##STR12##wherein R, R.sub.1, R.sub.2 and R.sub.3 are as defined above; and characterized in that the triol of formula IV is treated with a sulfonic acid chloride or with a halogenating agent, then with a strong base, to give the compound of formula V ##STR13##wherein R.sub.1, R.sub.2 and R.sub.3 are as defined above, and Lg is halogen or a OSO.sub.2 R.sup.IV group wherein in R.sup.IV is a (C.sub.1-4)alkyl group or an optionally methyl-substituted phenyl group, which is subdued to a reaction for substituting the Lg leaving group thus yielding the compound of formula VI ##STR14##wherein R.sub.1, R.sub.2 and R.sub.3 are as defined above, which is treated with 1,2,4-triazole in basic medium and gives the compound of formula VII.