Synthesis
The general procedure for the synthesis of 2,6-difluoro-4-nitroaniline from 3,4,5-trifluoronitrobenzene was as follows: 3,4,5-trifluoro-1-nitrobenzene (5 g, 28.4 mmol) was dissolved in a methanol solution of 7N ammonia (30 mL) and the reaction was stirred at 80°C for 2 days. After completion of the reaction, the mixture was cooled to room temperature, diluted with water (50 mL) and extracted with ethyl acetate (3 x 100 mL). The organic phases were combined, washed sequentially with water (2 × 50 mL), dried over anhydrous magnesium sulfate, and subsequently concentrated under reduced pressure. The crude product was purified by fast silica gel column chromatography (eluent ratio of ethyl acetate:hexane=20:80) to afford the target compound 2,6-difluoro-4-nitroaniline (1.53 g, 31% yield). The product was detected by ESI-MS with m/z of 196 ([M+Na]+, 100%); 1H NMR (600 MHz, DMSO-d6) δppm: 7.82-7.95 (m, 2H), 6.86 (s, 2H).
