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

HRID 1600702Notes

Reaction equation

HRID 1600702 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-349542d2a6864f8b8f9dd9cedfef6abb
Source dataset
uspto-grants-1999_11
Patent number
US05977107

Reaction notes

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