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

HRID 53774Notes

Reaction equation

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

Participants

Conditions

Temperature: 0 °C

Procedure

To a solution of 7-bromo-5-trifluoromethyl-1,4-dihydro-2,3-quinoxalinedione (31 mg, 0.10 mmol) in concentrated H2SO4 (0.5 mL) at 0° C. was added KNO3 (11 mg, 0.109 mmol, Baker). The mixture was stirred at 0° C. for 0.5 h, then at room temperature for 12 h and it was poured into ice water (2 g). The precipitate was collected by filtration, affording 32 mg (91.4%) of crude title compound. It was dissolved in 1N KOH (1 mL) and filtered. The filtrate was acidified to pH 2 with 4N HCl to give a brown precipitate, which was collected by filtration, and dried at 50° C. for 4 h, affording pure title compound (28 mg, 79.3%) as a yellow powder. Mp: 292°-94° C., IR (KBr, cm-1): 3412, 3068, 3937, 1718, 1556, 1387. 1H NMR (DMSO-d6): δ 7.644 (s, 1H, 11.721 (s, 1H), 12.423 (s, 1H). HRMS: calcd for C9H3ClF3N3O4 (M+) m/z: 352.9258, found: 352.9259.

Workup

waitat room temperature for 12 h
filtrationThe precipitate was collected by filtration
customaffording 32 mg (91.4%) of crude title compound
filtrationfiltered
customto give a brown precipitate, which
filtrationwas collected by filtration
customdried at 50° C. for 4 h

Sources & evidence

ORD record: ord-74001c90ef7f40e9af54a1f2dbc71e73
Source dataset: uspto-grants-1997_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05620979

Reaction notes

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