Potassium Nitrate → Acea-1031

HRID 54327Notes

Reaction equation

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

Participants

Conditions

Temperature: 0 °C

Procedure

The procedure of Cheeseman, G. W. H., J. Chem. Soc. 1170 (1962) was adapted. To a stirred suspension of 6,7-dibromo-1,4-dihydro-2,3-quinoxalinedione (576 mg, 1.8 mMol) in concentrated H2SO4 (6 mL) at 0° C. for 30 min. was added KNO3 (220 mg, 2.18 mMol, Baker) in one portion. The mixture was stirred at 0° C. for 3 h then at room temperature for one day. The color of mixture was changed from red to yellow brown. Then it was poured into ice (60 g) resulting in the separation of a bright yellow precipitate, which was collected by filtration and washed with distilled water (2×2 mL) followed by ethanol (2×1 mL) to get 498 mg of crude 5-nitro-6,7-dibromo-1,4-dihydro-2,3-quinoxalinedione (76%, contains minor impurities by NMR). Crystallization from DMSO/H2O gave pure 5-nitro-6,7-dibromo-1,4-dihydro-2,3-quinoxalinedione as bright yellow microcrystals; mp: 352°-354° C. (dec.). IR (KBr, cm-1): 3387; 3256; 1756; 1700; 1537. NMR (1H, DMSO-d6): δ7.475 (s, 1H); 12.217 (s, 1H); 12.265 (s, 1H). HRMS: calcd for C8H3N3O4Br2 (M+) m/z: 362.8489; found: 362.8509.

Workup

waitat room temperature for one day
customresulting in the separation of a bright yellow precipitate, which
filtrationwas collected by filtration
washwashed with distilled water (2×2 mL)

Sources & evidence

ORD record: ord-16f1f1872f2949f68aabf2087a8ad3e0
Source dataset: uspto-grants-1997_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05622952

Reaction notes

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