反应详情

Finely powdered potassium nitrate (1.01 g, 10 mmol) is added during 5 min. to a stirred solution of 6-chloro-2,3-dihydroxyquinoxaline (1.97 g, 10 mmol) in 50 ml of concentrated sulfuric acid at 0° C. After 1 h, the ice bath was removed and stirring continued for 2.5 h at room temperature. The mixture is poured into 200 ml of ice/water and the precipitate is isolated, washed with water, ethanol, and ether. The product is dissolved in 70 ml of hot 2N sodium hydroxide, filtered while hot, and reprecipitated with concentrated hypochloric acid to give 2.12 g (88%) of pure title compound. 3H-NMR (DMSO-d6): δ 7.23 (s, 1H, H-5); δ 7.82 (s, 1H, h-8); δ 12.1 (broad s, 2H, 2NH).

1. customthe ice bath was removed
2. waitcontinued for 2.5 h at room temperature
3. additionThe mixture is poured into 200 ml of ice/water
4. customthe precipitate is isolated
5. washwashed with water, ethanol, and ether
6. dissolutionThe product is dissolved in 70 ml of hot 2N sodium hydroxide
7. filtrationfiltered while hot, and
8. customreprecipitated with concentrated hypochloric acid