Water → 9H-Indeno[1,2-b]pyrazine-3,9(4H)-dione 9-(1,2-dimethylethylene) acetal

HRID 263900Notes

Reaction equation

HRID 263900 reaction equation
[N:1]1[C:2]2[C:14](=[O:15])[C:13]3[CH:12]=[CH:11][CH:10]=[CH:9][C:8]=3[C:3]=2[NH:4][C:5](=[O:7])[CH:6]=1.[C:16]1(C)C=C[C:19](S(O)(=O)=O)=[CH:18][CH:17]=1.[OH2:27]>C1(C)C=CC=CC=1.CC(O)C(O)C>[CH3:16][CH:17]1[O:27][C:5]2([NH:4][C:3]3[C:8]4[CH:9]=[CH:10][CH:11]=[CH:12][C:13]=4[C:14](=[O:15])[C:2]=3[N:1]=[CH:6]2)[O:7][CH:18]1[CH3:19]

Participants

6

Reactant 3

HCID 962WaterHCID 6101p-Toluenesulfonic acidHCID 190359769H-Indeno[1,2-b]pyrazine-3,9(4H)-dione

Product 1

HCID 677228019H-Indeno[1,2-b]pyrazine-3,9(4H)-dione 9-(1,2-dimethylethylene) acetalYield 78.5%

Reagents, catalysts & solvents 2

HCID 2622,3-ButanediolSolventHCID 1140TolueneSolvent

Procedure

A suspension of 9H-indeno[1,2-b]pyrazine-3,9(4H)-dione (2.0 g, 10.09 mmol) in toluene (50 ml), 2,3-butanediol (20 ml) and p-toluenesulfonic acid (40 mg) was refluxed with water separation for 20 hours. The reaction mixture was evaporated in vacuo to dryness and another portion of toluene, 2,3-butanediol and p-toluenesulfonic acid was added and the mixture was refluxed again for 20 hours. After evaporation to dryness, the residue was suspended in ethanol (10 ml) and the precipitate was filtered off and washed with ethanol and dried to give 2.14 g (78.5%) of the title compound as a mixture of isomers. 1H-NMR (DMSO-d6, δ): 1.24-1.4 (m, 6H), 4.03-4.87 (m, 2H), 7.42-7.91 (m, 5H), 12.6 (s, 1H).

Workup

  1. customThe reaction mixture was evaporated in vacuo to dryness
  2. additionanother portion of toluene, 2,3-butanediol and p-toluenesulfonic acid was added
  3. temperaturethe mixture was refluxed again for 20 hours
  4. customAfter evaporation to dryness
  5. filtrationthe precipitate was filtered off
  6. washwashed with ethanol
  7. customdried

Sources & evidence

ORD record
ord-cd4524f72ee9420c8230d0fdac19e1b3
Source dataset
uspto-grants-1997_07
Patent number
US05646146

Reaction notes

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