Oxalic acid dihydrate → 5,7-Dimethyl-1,4-dihydroquinoxaline-2,3-dione

HRID 1781032Notes

Reaction equation

HRID 1781032 reaction equation
[NH2:1][C:2]1[C:7]([CH3:8])=[CH:6][C:5]([CH3:9])=[CH:4][C:3]=1[NH2:10].O.O.[C:13](O)(=[O:17])[C:14](O)=[O:15]>Cl>[CH3:8][C:7]1[CH:6]=[C:5]([CH3:9])[CH:4]=[C:3]2[C:2]=1[NH:1][C:13](=[O:17])[C:14](=[O:15])[NH:10]2

Participants

4

Reactant 2

HCID 61373Oxalic acid dihydrateHCID 3613321(2-Amino-3,5-dimethylphenyl)amine

Product 1

HCID 6557775,7-Dimethyl-1,4-dihydroquinoxaline-2,3-dioneYield 87.2%

Reagents, catalysts & solvents 1

HCID 313Hydrochloric AcidSolvent

Procedure

A mixture of 1,2-diamino-4,6-dimethylbenzene (424 mg, 3.11 mmole) and oxalic acid dihydrate (432 mg, 3.43 mmole, used as received) in 4N HCl (20 mL) was refluxed at 120°-5° C. for 3 h, then cooled to room temperature. The mixture was centrifuged and the supernatant was removed. The yellow solid was washed with cold water (2×2 mL), collected by filtration, and dried in vacuo for 2 h, affording 516 mg of crude 5,7-dimethyl-1,4-dihydro-2,3-quinoxalinedione (87%) as a yellow powder. The crude product was taken up in 1N NaOH (10 mL) and filtered. The filtrate was acidified to pH=3, affording the pure title compound (490 mg) as a light yellow powder; mp: 345°-347° C. (dec); IR (KBr, cm-1): 3460, 3190, 2986, 1716, 1709, 1630. 1H NMR (DMSO-d6): δ11.858 (s, 1H), 11.173 (s, 1H), 6.766 (s, 1H), 6.745 (s, 1H), 2.280 (s, 3), 2.211 (s, 3). HRMS: calcd for C10H10N2O2 (M+) m/z: 190.0714; found: 190.0744.

Workup

  1. temperaturewas refluxed at 120°-5° C. for 3 h
  2. customthe supernatant was removed
  3. washThe yellow solid was washed with cold water (2×2 mL)
  4. filtrationcollected by filtration
  5. customdried in vacuo for 2 h

Sources & evidence

ORD record
ord-43fa774a4335414e86153f409864b47c
Source dataset
uspto-grants-1997_05
Patent number
US05631373

Reaction notes

Loading…