Patent ID: 6596907
Filing Date: 2003-07-22
Classification: A61P,C07C

Abstract:
A process for the preparation of a 4,4â€²-dihalogen-o-hydroxydiphenyl compound of formula (1), which comprisesa) halogenating an alkoxyphenol of formula (6) with a halogenating agent selected from the group consisting of elemental chlorine and sulfuryl chloride, in the presence of an aromatic, aliphatic or cycloaliphatic hydrocarbon in step (a1), reacting the resulting halogenated phenol compound of formula (5) with a p-dihalobenzene of formula (4a) in the presence of copper and/or copper salts and alkali hydroxide to the diphenyl ether compound of formula (2) in step (a2) wherein the alkali hydroxide is used in less than an equivalent amount, with subsequent ether fission with AlCl3 in an inert solvent to the diphenyl ether compound of formula (1) in step (a3), or b) reacting an alkoxyphenol of formula (6) with the halobenzene of formula (4b) to the compound of formula (3) in step (b1), halogenating this compound in step (b2), with subsequent ether fission of the resulting compound of formula (2) with AlCl3 in an inert solvent to the diphenyl ether compound of formula (1) in step (b3), in correspondence with the following reaction scheme: whereinR1 is C1-C5alkyl; R2 is hydrogen; chloro or bromo; and Hal1, Hal2 and Hal3 are each independently of one another a halogen atom.