Oxalic acid dihydrate → 7-Bromo-5-trifluoromethyl-1,4-dihydro-2,3-quinoxalinedione
Reaction equation
[NH2:1][C:2]1[C:7]([NH2:8])=[CH:6][C:5]([Br:9])=[CH:4][C:3]=1[C:10]([F:13])([F:12])[F:11].O.O.[C:16](O)(=[O:20])[C:17](O)=[O:18]>Cl.[OH-].[Na+]>[Br:9][C:5]1[CH:6]=[C:7]2[C:2]([NH:1][C:16](=[O:20])[C:17](=[O:18])[NH:8]2)=[C:3]([C:10]([F:13])([F:11])[F:12])[CH:4]=1Participants
Procedure
A mixture of 2,3-diamino-5-bromobenzotrifluoride (150 mg, 0.612 mmol) and oxalic acid dihydrate (81 mg, 0.643 mmol, used as received) in 2N HCl (4 mL) was refluxed at 120°-5° C. for 3 h, then cooled to room temperature. The mixture was centrifuged and the liquid layer was removed. The yellow solid was washed twice by cold water (2×2 mL), collected by filtration, and dried at 60° C. for 2 h, affording 150 mg of crude title compound (81.9%) as a red powder. The crude compound was dissolved in 1N NaOH (6 mL) and filtered. The filtrate was acidified to pH=6, affording 135 mg of title compound. Recrystallization from DMSO/H2O gave 125 mg of pure title compound (68.3%) as red microcrystals. Mp: 307°-9° C. (dec. from 290° C.). IR (KBr, cm-1) 3412, 3250, 1756, 1706, 1606; 1H NMR (DMSO-d6): δ 7.514 (d, 1H, J=1.5 Hz); 7.556 (d, 1H, J=1.5 Hz); 11.342 (s, 1H); 12.220 (s, 1H). HRMS: calcd for C9H4BrF3N2O2 (M+) m/z: 307.9407; found: 307.9420.
Workup
- temperaturewas refluxed at 120°-5° C. for 3 h
- customthe liquid layer was removed
- washThe yellow solid was washed twice by cold water (2×2 mL)
- filtrationcollected by filtration
- customdried at 60° C. for 2 h
- customaffording 150 mg of crude title compound (81.9%) as a red powder
- filtrationfiltered
Sources & evidence
- ORD record
- ord-ff5771b2bc68468b973da63eda30837f
- Source dataset
- uspto-grants-1997_04
- Patent number
- US05620979
Reaction notes
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