Process for the preparation of 4-alkoxy-3,5,6-trifluorophthalic acids and 3-alkoxy-2,4,5-trifluorobenzoic acids

摘要

Prodn. of 4-alkoxy-3,5,6-trifluoro-phthalic acids of formula (I) or 3-alkoxy-2,4,5-trifluoro-benzoic acids of formula (II) comprises: (a) reacting tetrafluorophthalic acid (IIIa) or tetrafluorophthalic anhydride (IIIb) with an alcohol of formula ROH and a water-soluble base in water at elevated temp., and isolating (I); and opt. (b) decarboxylating (I) at 70-180 degrees C in the presence of a basic solvent and opt. an inert solvent, and isolating (II): R = an opt. fluorinated 1-5C alkyl, 3-5C cycloalkyl or araliphatic gp..