反应详情

To a suspension of 4-(2,6-difluorophenyl)thiomorpholine 1,1-dioxide (Step 1, 300 g, 1.21 mol) in 3 L of acetic acid, nitric acid (255 mL, ca. 6 mol, fuming, 90%) is added over 30 minutes at ambient temperature. A yellow precipitate forms within minutes and increases over time. The reaction is kept at room temperature for 18 h and is then poured into 6 L of water. After stirring for 2 h, the yellow suspension is filtered. The precipitate is washed with water (1.5 L×3) and ethanol (0.5 L×2) and dried at 50° C. overnight to give the title compound, 1H NMR (DMSO-d6) δ 8.05 (m, 2H), 3.69 (m, 4H), 3.26 (m, 4H).

1. additionis added over 30 minutes at ambient temperature
2. waitA yellow precipitate forms within minutes
3. temperatureincreases over time
4. filtrationthe yellow suspension is filtered
5. washThe precipitate is washed with water (1.5 L×3) and ethanol (0.5 L×2)
6. customdried at 50° C. overnight