反应详情

To 5,6,7-trifluoro-1,4-dihydro-2,3-quinoxalinedione (93 mg, 0.43 mmol) is added concentrated sulfuric acid (0.5 mL). While the flask is in an ice bath, KNO3 is slowly added, giving a brown mixture, which is stirred overnight. The reaction mixture, now dark red, is then added to ice water (5 mL), instantly giving an orange precipitate, which is collected by centrifugation. The powder is crystallized from EtOH (5 mL) and dried in vacuo to yield 24 mg (20%) of pale orange microcrystals. 1H NMR (DMSO-d6), 11.9 (br s, 1H), 12.6 (br s, 1H).

1. customWhile the flask is in an ice bath
2. customgiving a brown mixture, which
3. custominstantly giving an orange precipitate, which
4. customis collected by centrifugation
5. customThe powder is crystallized from EtOH (5 mL)
6. customdried in vacuo
7. customto yield 24 mg (20%) of pale orange microcrystals