Diethyl Oxalate → 5-Bromo-7-fluoro-1,4-dihydroquinoxaline-2,3-dione

HRID 439448Notes

Reaction equation

HRID 439448 reaction equation
[C:1]([O:8]CC)(=O)[C:2]([O:4]CC)=O.[NH2:11][C:12]1[CH:17]=[C:16]([F:18])[CH:15]=[C:14]([Br:19])[C:13]=1[NH2:20]>>[Br:19][C:14]1[CH:15]=[C:16]([F:18])[CH:17]=[C:12]2[C:13]=1[NH:20][C:2](=[O:4])[C:1](=[O:8])[NH:11]2

Participants

3

Reactant 2

HCID 7268Diethyl OxalateHCID 140299893-Bromo-5-fluorobenzene-1,2-diamine

Product 1

HCID 211900395-Bromo-7-fluoro-1,4-dihydroquinoxaline-2,3-dione

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 (3.31 mL, 24.4 mmol) and 1,2-diamino-3-bromo-5-fluorobenzene (500 mg, 2.44 mmol) was heated to reflux under N2 for 5 h. The reaction mixture was dark brown. The reaction was allowed to cool to room temperature and the solid collected by vacuum filtration and rinsed with EtOH (30 mL). The brown solid was air dried for 1 hr to give 250 mg (39.6% crude yield). A portion of this solid was removed and dissolved in 1N NaOH (10 mL) and a few insoluble particles were removed by gravity filtration. The solution was treated with decolorizing carbon and the mixture was filtered through a pad of celite and the resulting solution acidified with 1N HCl. White crystals formed that were isolated by vacuum filtration and washed with water (20 mL). The crystals were dried in a drying pistol (0.05 torr, 78° C.) to yield 54.1 mg, mp 308°-310° C. (dec). 1H NMR (d6 -DMSO) δ6.2 (dd, 1H, JH6-8 =2.7, JH-F =9.3, ArH), 7.35 (dd, 1H, JH6-8 =2.4, JHF =8.4 Hz), 11.1 (br s, 1H, NH), 12.1 (brs, 1H, NH). EIHRMS calc. for C8H4BrFN2O2 : 257.9440, found 257.9455.

Workup

  1. temperaturewas heated
  2. temperatureto reflux under N2 for 5 h
  3. filtrationthe solid collected by vacuum filtration
  4. washrinsed with EtOH (30 mL)
  5. customdried for 1 hr
  6. customto give 250 mg (39.6% crude yield)
  7. customA portion of this solid was removed
  8. dissolutiondissolved in 1N NaOH (10 mL)
  9. customa few insoluble particles were removed by gravity filtration
  10. additionThe solution was treated with decolorizing carbon
  11. filtrationthe mixture was filtered through a pad of celite
  12. customWhite crystals formed
  13. customthat were isolated by vacuum filtration
  14. washwashed with water (20 mL)
  15. customThe crystals were dried in a drying pistol (0.05 torr, 78° C.)
  16. customto yield 54.1 mg, mp 308°-310° C. (dec)

Sources & evidence

ORD record
ord-2fde8d6eaf9f4dbea217c8dfa9fa38c2
Source dataset
uspto-grants-1996_05
Patent number
US05514680

Reaction notes

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