Diethyl Oxalate → 5,6,7,8-Tetrafluoro-1,4-dihydro-2,3-quinoxalinedione

HRID 439445Notes

Reaction equation

HRID 439445 reaction equation
[C:1]([O:8]CC)(=O)[C:2]([O:4]CC)=O.[F:11][C:12]1[C:13]([NH2:22])=[C:14]([NH2:21])[C:15]([F:20])=[C:16]([F:19])[C:17]=1[F:18]>>[F:11][C:12]1[C:17]([F:18])=[C:16]([F:19])[C:15]([F:20])=[C:14]2[C:13]=1[NH:22][C:2](=[O:4])[C:1](=[O:8])[NH:21]2

Participants

3

Reactant 2

HCID 7268Diethyl OxalateHCID 27739573,4,5,6-Tetrafluorobenzene-1,2-diamine

Product 1

HCID 211899685,6,7,8-Tetrafluoro-1,4-dihydro-2,3-quinoxalinedione

Procedure

The title compound (Allison, et al., J. Fluorine Chem. 1:59 (1971)) was prepared using an adaptation of the method of Cheeseman (Cheeseman, G. W. H., J. Chem. Soc. 1171 (1962)). A mixture of diethyl oxalate (2.86 mL, 4.1 mmol) and 3,4,5,6-tetrafluoro-1,2-diaminobenzene (380 mg, 2.11 mmol) was heated to reflux with stirring under N2 for 8 h. The reaction was cooled to room temperature and a small amount of purple precipitate was observed. The excess diethyl oxalate was evaporated and the resulting solid was suspended in 20 ml hexanes, vacuum filtered and the solid rinsed with hexanes (20 mL) and ethyl acetate (10 mL). The solid was air dried to yield 244.8 mg (49.9%). mp 330°-331° C. (lit. ca. 300° C. dec.). 1H NMR (d6 -DMSO) δ12.33 (br s, NH). 19F NMR (C6F6 external standard, δ-162.9), δ-157.7(m), -167.9(m).

Workup

  1. temperaturewas heated
  2. temperatureto reflux
  3. customThe excess diethyl oxalate was evaporated
  4. filtrationvacuum filtered
  5. washthe solid rinsed with hexanes (20 mL) and ethyl acetate (10 mL)
  6. customdried
  7. customto yield 244.8 mg (49.9%)

Sources & evidence

ORD record
ord-994708aecd1e41a6b158d8fbdad8d23e
Source dataset
uspto-grants-1996_05
Patent number
US05514680

Reaction notes

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