反应详情

温度

55 °C

To a solution of 4-amino-2,6-dichloropyridine (1.07 g, 6.56 mmol) in conc H2SO4 (3.5 mL) was added 0.50 mL of 70% HNO3 (7.94 mmol) at room temperature. The mixture was stirred at 55° C. for 15 h, then poured into ice-H2O (70 mL). To this mixture was added 40% aq. NaOH slowly to adjust the pH to 10. The precipitate was filtered, washed with water and dried to give 1.052 g (77%) of 23 as a pale yellow powder, mp 136°-8° C. 1H NMR (CDCl3) δ 6.116 (bs, 2H), 6.750 (s, 1H). It was used for the next reaction without further purification.

1. filtrationThe precipitate was filtered
2. washwashed with water
3. customdried