Sulfuric Acid → (4S)-4-Ethyl-7,8-dihydro-4-hydroxy-1H-pyrano(3,4-f)indolizine-3,6,10(4H)-trione

HRID 868314Notes

Reaction equation

HRID 868314 reaction equation
[CH2:1]([C@:3]([OH:31])([C:15]1[CH:23]=[C:22]2[N:18]([CH2:19][CH2:20][C:21]32OCC[O:24]3)[C:17](=[O:28])[C:16]=1[CH2:29][OH:30])[C:4](N[C@@H](C1C=CC=CC=1)C)=[O:5])[CH3:2].OS(O)(=O)=O.ClCCl>C(COC)OC>[CH2:1]([C@:3]1([OH:31])[C:15]2[CH:23]=[C:22]3[N:18]([CH2:19][CH2:20][C:21]3=[O:24])[C:17](=[O:28])[C:16]=2[CH2:29][O:30][C:4]1=[O:5])[CH3:2]

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 6344DichloromethaneHCID 11133734(S)-alpha-Ethyl-1,1-(ethylenedioxy)-alpha-hydroxy-6-(hydroxymethyl)-N-[(R)-1-phenylethyl]-5-oxo-1,2,3,5-tetrahydroindolizine-7-acetamide

Product 1

HCID 10220900(4S)-4-Ethyl-7,8-dihydro-4-hydroxy-1H-pyrano(3,4-f)indolizine-3,6,10(4H)-trioneYield 62.9%

Reagents, catalysts & solvents 1

HCID 80711,2-DimethoxyethaneSolvent

Procedure

Dissolved in 15 ml of dimethoxyethane was 815 mg of the compound (VI) obtained in the above procedure (1), followed by an addition of 5 ml of 2N H2SO4. The thus-prepared solution was heated with stirring for 20 hours under a nitrogen gas stream. After completion of the reaction, 150 ml of dichloromethane was added and the resultant mixture was washed with water. The organic layer was then dried over anhydrous sodium sulfate and the solvent was distilled off. The residue was recrystallized from a mixed solvent of ethanol and petroleum ether to obtain 315 mg of the title compound as colorless needle-like crystals.

Workup

  1. customobtained in the above procedure (1)
  2. temperatureThe thus-prepared solution was heated
  3. additionwas added
  4. washthe resultant mixture was washed with water
  5. dry with materialThe organic layer was then dried over anhydrous sodium sulfate
  6. distillationthe solvent was distilled off
  7. customThe residue was recrystallized from a mixed solvent of ethanol and petroleum ether

Sources & evidence

ORD record
ord-107818bd1ed84e0eab1f153f6d1c60b1
Source dataset
uspto-grants-1988_10
Patent number
US04778891

Reaction notes

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