Patent ID: 7348450
Filing Date: 2008-03-25
Classification: C07C,C07D

Abstract:
1. A method for preparing a compounds of formula: or an enol thereof, or an E or Z isomer thereof, in which X is in each case independently of one another fluorine, chlorine or bromine, and in which R 1 is alkyl, cycloalkyl, aryl or aralkyl, comprising (a) initially converting a compound of formula: in which X has the stated meaning, by reacting the hydroxyl group of the compound of formula II with a compound of the formula (R 2 O) 2 SO 2 or with a compound of the formula Y—R 2 in which Y is tosyl, chlorine, bromine or iodine, and in which R 2 is in each case alkyl, cycloalkyl, or benzyl, into a compound of formula: in which R 2 and X each has the above mentioned meaning, and (b) converting the compound of formula III by reaction with a metal alcoholate of the formula R 1 O − 1/nM n+ in which R 1 has the above-mentioned meaning and M n+ is an alkali metal or alkaline earth metal cation and n=1 or 2, and (c) further treating with a strong acid, into a compound of formula I and/or an enol thereof and/or an E or Z isomer thereof.