2,5-Bis(trifluoromethyl)aniline is a haloalkul substituted aniline used in the preparation of anti-benign prostatic hyperplasia drug, Dutasteride (D735000).
Example 8: To an autoclave was added 1.05 g of Raney nickel catalyst (10 wt%) and 100 mL of isopropanol followed by 10.0 g of 2,5-bis(trifluoromethyl)nitrobenzene. Hydrogen was passed under stirring until the pressure reached 5 kg/cm2 and the temperature was raised to 70 °C. The reaction was continued at 70-90°C for 8 hours. After completion of the reaction, the temperature was allowed to drop to room temperature, the hydrogen pressure was released, the catalyst was removed by filtration and the filtrate was washed with isopropanol. The filtrate was concentrated to give 6.42 g of 2,5-bis(trifluoromethyl)aniline in 73% yield and 99.4% GC purity. The structure of the product was confirmed by GC-MS, 1H-NMR and 19F-NMR analysis.
[1] Patent: EP1468983, 2004, A1. Location in patent: Page 6
[2] Journal of the American Chemical Society, 1953, vol. 75, p. 4967
[3] Patent: WO2011/150156, 2011, A2. Location in patent: Page/Page column 132
