2-Fluoro-4-(trifluoromethyl)aniline

115029-24-8

69409-98-9

General procedure for the synthesis of 4-amino-3-fluorobenzotrifluoride from 2-fluoro-4-(trifluoromethyl)benzoic acid: 2-fluoro-4-(trifluoromethyl)benzoic acid (1 kg, 4.805 mol, 1.00 eq.) and CuCl (14.26 g, 0.144 mol, 0.03 eq.) were dissolved in 0-BuOH (11.7 L). Triethylamine (TEA, 533.8 g, 5.286 mol, 1.10 eq.) was added slowly and dropwise at room temperature. The reaction mixture was then heated to 50 °C and diphenylphosphoryl azide (DPPA, 1393 g, 5.045 mol, 1.05 eq.) was added slowly dropwise at 50-60 °C. The reaction mixture was heated at 80-85 °C overnight. After completion of the reaction, the solution was concentrated under reduced pressure. The residue was dissolved in water and filtered. The filtrate was extracted with ethyl acetate and the organic layer was dried with anhydrous Na2SO4, filtered and concentrated under reduced pressure. The residue was dissolved in tert-butyl methyl ether (TBME) and HCl gas was passed into it for 2 hours. The filtrate was collected, dissolved in water and alkalized with 2M NaOH solution. The alkalized solution was extracted with TBME and the organic layer was dried and concentrated under reduced pressure to give 2-fluoro-4-(trifluoromethyl)aniline (498 g, 58% yield) as a red oil. The product was confirmed by 1H-NMR (300 MHz, CDCl3): δ 7.27 (m, 2H), 6.82 (m, 1H), 4.05 (bs, 2H); mass spectrum (MS): m/z = 180 [M + H]+.