[OH:1][CH2:2][C:3]1[CH:11]=[CH:10][C:6]([C:7]([OH:9])=[O:8])=[C:5]([C:12]([F:15])([F:14])[F:13])[CH:4]=1.[C:16]1(C)C=CC=CC=1.S(=O)(=O)(O)O>CO>[CH3:16][O:8][C:7](=[O:9])[C:6]1[CH:10]=[CH:11][C:3]([CH2:2][OH:1])=[CH:4][C:5]=1[C:12]([F:13])([F:14])[F:15]To a solution of 4-hydroxymethyl-2-trifluoromethyl-benzoic acid (Example I8) (9.07 g) in methanol (250 ml) was added toluene (250 ml) and concentrated sulfuric acid (4.5 ml). The reaction mixture was stirred at 80° C. for 16 hours. The methanol was removed and the residue diluted with aqueous sodium hydrogen carbonate (saturated) (150 ml) and ethyl acetate (150 ml). The phases were separated and the aqueous layer was extracted with more ethyl acetate (2×150 ml). The combined organic extracts were washed with brine, dried over sodium sulfate and concentrated to give 4-hydroxymethyl-2-trifluoromethyl-benzoic acid methyl ester (5.97 g) as a colorless oil. 1H-NMR (CDCl3, 400 MHz): 8.76-7.27 (m, 3H), 4.78 (s, 2H), 3.93 (s, 3H), 2.5 (br s, 1H).
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