Methane → 5-Bromo-6,7-difluoro-1,4-dihydro-2,3-quinoxalinedione

HRID 54294Notes

Reaction equation

HRID 54294 reaction equation
[C:1]([O:8]CC)(=O)[C:2]([O:4]CC)=O.[Br:11][C:12]1[C:13]([NH2:21])=[C:14]([NH2:20])[CH:15]=[C:16]([F:19])[C:17]=1[F:18].C>[OH-].[Na+]>[Br:11][C:12]1[C:17]([F:18])=[C:16]([F:19])[CH:15]=[C:14]2[C:13]=1[NH:21][C:2](=[O:4])[C:1](=[O:8])[NH:20]2

Participants

5

Reactant 3

HCID 297MethaneHCID 7268Diethyl OxalateHCID 199585973-Bromo-4,5-difluorobenzene-1,2-diamine

Product 1

HCID 199585655-Bromo-6,7-difluoro-1,4-dihydro-2,3-quinoxalinedione

Reagents, catalysts & solvents 1

HCID 14798Sodium HydroxideSolvent

Procedure

The title compound was prepared using an adaptation of the method of Cheeseman. (Cheeseman, G. W. H. J. Chem. Soc. 1171 (1962)). A mixture of diethyl oxalate (2.70 g, 18.5 mmol) and 3-bromo-4,5-difluoro-1,2-diaminobenzene (410 mg, 1.85 mmol) was heated to reflux under N2 for 15 h. The reaction was allowed to cool to room temperature and the dark-brown solid collected by vacuum filtration and rinsed with EtOH (20 mL) and air dried to give 215 mg (42%). A portion of this solid (150 mg) was taken and dissolved in 20 mL 1N NaOH with heating. The solution was treated with activated charcoal and filtered through a pad of Celite. The resulting solution was carefully acidified with 1N HCl (pH=1). Pale yellow needles slowly formed in the solution and were collected by vacuum filtration, rinsed with 20 mL of H2O and dried under vacuum (0.1 torr, 78° C.) to yield 67.8 mg of powdery pale yellow crystals, mp 306°-310° C. (dec). 1H NMR (d6 -DMSO) δ7.09 (dd, 1H, J=7.5, H-8), 11.3 (br s, 1H, NH), 12.1 (br s, 1H, NH). EIMS m/z 278 (M+2, 75), 276 (M+, 77), 250 (56), 248 (57), 141 (bp). EIHRMS calc. for C8H4BrF2N2O2 275.9346, found 275.9331.

Workup

  1. temperaturewas heated
  2. temperatureto reflux under N2 for 15 h
  3. filtrationthe dark-brown solid collected by vacuum filtration
  4. washrinsed with EtOH (20 mL) and air
  5. customdried
  6. customto give 215 mg (42%)
  7. temperaturewith heating
  8. filtrationfiltered through a pad of Celite
  9. customPale yellow needles slowly formed in the solution
  10. filtrationwere collected by vacuum filtration
  11. washrinsed with 20 mL of H2O
  12. customdried under vacuum (0.1 torr, 78° C.)

Sources & evidence

ORD record
ord-323771094f0e44679c7087e7c36d9229
Source dataset
uspto-grants-1997_04
Patent number
US05622952

Reaction notes

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