Potassium Nitrate → 6-Bromo-5-nitro-7-trifluoromethyl-1,4-dihydro-2,3-quinoxalinedione

HRID 54374Notes

Reaction equation

[Br:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][C:11]=1[C:12]([F:15])([F:14])[F:13])[NH:8][C:7](=[O:16])[C:6](=[O:17])[NH:5]2.[N+:18]([O-])([O-:20])=[O:19].[K+]>OS(O)(=O)=O>[Br:1][C:2]1[C:3]([N+:18]([O-:20])=[O:19])=[C:4]2[C:9](=[CH:10][C:11]=1[C:12]([F:14])([F:15])[F:13])[NH:8][C:7](=[O:16])[C:6](=[O:17])[NH:5]2

Participants

Conditions

Temperature: 25 °C

Procedure

To a solution of 6-bromo-7-trifluoromethyl-1,4-dihydro-2,3-quinoxalinedione (40 mg, 0.13 mmol) in concentrated H2SO4 (0.5 mL) at 25° C. was added KNO3 (16 mg, 0.15 mmol, Baker). The mixture was stirred at 25° C. for 30 h and poured into ice water (2 g). The yellow precipitate was collected by filtration and the solid was dissolved in 1N KOH (10 mL). It was filtered and the filtrate was acidified to pH=5 with 4N HCl (2.5 mL) to give a yellow precipitate. The precipitate was collected and dried in the air at 50° C. for 4 h, affording the title compound (34 mg, 74%) as a yellow powder. Recrystallization from DMSO/H2O gave 18 mg (40%) of the title compound as yellow needles. Mp: 333°-5° C. (dec.); IR (KBr, cm-1): 3428, 3308, 3251, 3207, 1761, 1698, 1537, 600. 1H NMR (DMSO-d6): δ12.601 (br, 1H), 12.341 (s, 1H), 7.606 (s, 1H).

Workup

filtrationThe yellow precipitate was collected by filtration
dissolutionthe solid was dissolved in 1N KOH (10 mL)
filtrationIt was filtered
customto give a yellow precipitate
customThe precipitate was collected
customdried in the air at 50° C. for 4 h

Sources & evidence

ORD record: ord-51faf0efae5149bc80030001c037187c
Source dataset: uspto-grants-1997_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05622952

Reaction notes

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