Diethyl Oxalate → 6,7-Difluoroquinoxaline-2,3(1H,4H)-dione

HRID 1857374Notes

Reaction equation

HRID 1857374 reaction equation
[C:1]([O:8]CC)(=O)[C:2]([O:4]CC)=O.[F:11][C:12]1[C:17]([F:18])=[CH:16][C:15]([NH2:19])=[C:14]([NH2:20])[CH:13]=1>>[F:11][C:12]1[CH:13]=[C:14]2[C:15](=[CH:16][C:17]=1[F:18])[NH:19][C:1](=[O:8])[C:2](=[O:4])[NH:20]2

Participants

3

Reactant 2

HCID 7268Diethyl OxalateHCID 27367551,2-Diamino-4,5-difluorobenzene

Product 1

HCID 8228396,7-Difluoroquinoxaline-2,3(1H,4H)-dione

Procedure

The title compound (Sarges, R. et al., J. Med. Chem. 33:2240 (1990)) was prepared using an adaptation of the method of Cheeseman. (Cheeseman, G. W. H. J. Chem. Soc. 1171 (1962)). A mixture of diethyl oxalate (1.11 g, 7.63 mmol and 4,5-difluoro-1,2-diaminobenzene (110 mg, 0.763 mmol) was heated to reflux under N2 for 2 h. The reaction was allowed to cool to room temperature and the solid was collected by vacuum filtration, rinsed with hexanes, and air dried. This gray brown solid was recrystallized from 20 mL of EtOH and the brown-white crystals collected by vacuum filtration and the crystals further dried under vacuum (0.5 torr, 25° C.) to yield 45.3 mg (30.0%); mp>360° C. (lit.>310° C.); 1H NMR (d6 -acetone) δ 7.19 (t, 2H, ArH, JH-F =9.3), 10.9 (br s, 2H, NH).

Workup

  1. temperaturewas heated
  2. temperatureto reflux under N2 for 2 h
  3. filtrationthe solid was collected by vacuum filtration
  4. washrinsed with hexanes, and air
  5. customdried
  6. customThis gray brown solid was recrystallized from 20 mL of EtOH
  7. filtrationthe brown-white crystals collected by vacuum filtration
  8. customthe crystals further dried under vacuum (0.5 torr, 25° C.)
  9. customto yield 45.3 mg (30.0%)
  10. custommp>360° C. (lit.>310° C.)

Sources & evidence

ORD record
ord-72e9bd4c60f24615ba6a8b476be84dff
Source dataset
uspto-grants-2000_11
Patent number
US06147075

Reaction notes

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