| 摘要 |
The present invention relates to a process for the preparation of 4-alkoxy-3,5,6-trifluorophthalic acids of the formula <IMG> (1), in which R is an alkyl radical having 1 to 5 carbon atoms which may be monofluorinated or polyfluorinated, a cycloalkyl radical having 3 to 5 carbon atoms in the ring which may be monofluorinated or polyfluorinated, or an araliphatic radical which may be monofluorinated or polyfluorinated, or, if desired, of 3-alkoxy-2,4,5-trifluorobenzoic acids of the formula <IMG> (2), in which R is as defined above, which involves reacting tetrafluorophthalic acid or tetrafluorophthalic anhydride with an alcohol of the formula ROH in which R is as defined above and with a water-soluble base in water at elevated temperature, isolating the 4-alkoxy-3,5,6-trifluorophthalic acid formed and, if desired, decarboxylating the 4-alkoxy-3,5,6-trifluorophthalic acid in the presence of a basic solvent and, if desired, of an inert solvent at from 70 to 180.degree.C, and isolating the 3-alkoxy-2,4,5-trifluorobenzoic acid formed.
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