Methane → 5,7-Dibromo-1,4-dihydro-2,3-quinoxalinedione

HRID 439434Notes

Reaction equation

HRID 439434 reaction equation
[C:1]([O:8]CC)(=O)[C:2]([O:4]CC)=O.[Br:11][C:12]1[C:13]([NH2:20])=[C:14]([NH2:19])[CH:15]=[C:16]([Br:18])[CH:17]=1.C>[OH-].[Na+]>[Br:11][C:12]1[CH:17]=[C:16]([Br:18])[CH:15]=[C:14]2[C:13]=1[NH:20][C:2](=[O:4])[C:1](=[O:8])[NH:19]2

Participants

5

Reactant 3

HCID 297MethaneHCID 7268Diethyl OxalateHCID 1014513,5-Dibromo-1,2-benzenediamine

Product 1

HCID 105917505,7-Dibromo-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 (2.19 g, 15.0 mmol) and 3,5-dibromo-1,2-diaminobenzene (400 mg, 1.50 mmol) was heated to reflux under N2 for 6 h. The reaction was allowed to cool to room temperature and the pale brown shiny solid collected by vacuum filtration and rinsed with EtOH (20 mL) and air dried to give 264 mg (55%). 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 2N 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 50.0 mg of powdery white solid, mp 356°-358° C. (dec). 1H NMR (d6 -DMSO) δ7.21 (d, 1H, J=2.1, H-8), 7.53 (d, 1H, J=2.1, H-6), 11.1 (br s, 1H, NH), 12.1 (br s, 1H, NH). EIMS m/z 322 (M+4, 51.3), 320 (M+2, bp), 318 (M+, 53.9), 294 (32.2), 292 (62.6), 290 (28.7), 185 (24.3), 183 (25.2). EIHRMS calc. for C8H4Br2N2O2 317.8641, found 317.8642.

Workup

  1. temperaturewas heated
  2. temperatureto reflux under N2 for 6 h
  3. filtrationthe pale brown shiny solid collected by vacuum filtration
  4. washrinsed with EtOH (20 mL) and air
  5. customdried
  6. customto give 264 mg (55%)
  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) and
  12. customdried under vacuum (0.1 torr, 78° C.)

Sources & evidence

ORD record
ord-7208620e420e4be6b1b71fb7653aa0fb
Source dataset
uspto-grants-1996_05
Patent number
US05514680

Reaction notes

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