alpha,alpha,alpha,3-Tetrafluorotoluene → 2-Fluoro-6-(trifluoromethyl)benzoic acid

참여 물질

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반응 단계

A mixture of 3-fluorobenzotrifluoride (25.0 g, 0.15 mol) in tetrahydrofuran (200 ml) was cooled to -78° C. in a dry ice/acetone bath under nitrogen atmosphere. To this solution was added dropwise with rapid stirring N-butyl lithium (1.6M, 95.2 ml) at such rate that the temperature did not exceed -60° C. When the addition was complete, the mixture was allowed to stir at -78° C. for an additional five hours. The mixture was then poured over a slurry of dry ice/ether and allowed to come to room temperature. The solvent was removed by evaporation under reduced pressure to obtain a white solid residue. This solid was dissolved in a minimum amount of water, the solution was extracted with diethyl ether (2×100 ml) and the aqueous phase was acidified to pH 2 with dilute hydrochloric acid. An oil formed and this was dissolved in diethyl ether; the solution was washed several times with water and dried over magnesium sulfate. The solvent was removed by evaporation under reduced pressure to give a white solid. NMR analysis indicated this product was a mixture of the title compound and an isomer. A yield of 15.6 g (50 percent of theory) was obtained.

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