| 摘要 |
PURPOSE:To obtain the subject compound useful as an intermediate raw material for pharmaceuticals, agricultural chemicals, photosensitizing materials, liquid crystal materials, etc., by hydroxylating tetrafluorophthalic acid and then decarbonating the product. CONSTITUTION:Tetrafluorophthalic acid is hydroxylated in an alkaline aqueous solution (e.g. NaOH solution) at 20-100 deg.C to obtain 3,4,6-trifluoro-4- hydroxyphthalic acid. The product is heated in a solvent optionally in the presence of a catalyst to effect decarbonation reaction and obtain novel 2,4,5- trifluoro-3-hydroxybenzoic acid. The solvent is water, an aprotic polar solvent, a nitrogen-containing organic base free from N-H bond or their mixture, etc. Reaction of the above novel compound with an alkylation agent gives a novel 2,4,5-trifluoro-3-alkoxybenzoic acid which is a derivative of the above compound. |
