Sulfuric Acid → N-benzyl-1,2,3,4-tetrahydrocarbazole-3,4-dicarboximide

HRID 373986Notes

Reaction equation

HRID 373986 reaction equation
[CH2:1]([N:8]1[C:18](=[O:19])[CH:12]2[CH2:13][C:14](=O)[CH2:15][CH2:16][CH:11]2[C:9]1=[O:10])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.S(=O)(=O)(O)O.[C:25]1([NH:31]N)[CH:30]=[CH:29][CH:28]=[CH:27][CH:26]=1.C(=O)([O-])O.[Na+]>O.C(OCC)(=O)C.C(O)C>[CH2:1]([N:8]1[C:18](=[O:19])[CH:12]2[CH:11]([CH2:16][CH2:15][C:14]3[NH:31][C:25]4[C:30]([C:13]=32)=[CH:29][CH:28]=[CH:27][CH:26]=4)[C:9]1=[O:10])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

8

Reactant 4

HCID 1118Sulfuric AcidHCID 7516PhenylhydrazineHCID 516892Sodium BicarbonateHCID 28618042-benzyltetrahydro-1H-isoindole-1,3,5(2H,4H)-trione

Product 1

HCID 2865034N-benzyl-1,2,3,4-tetrahydrocarbazole-3,4-dicarboximideYield 29%

Reagents, catalysts & solvents 3

HCID 702EthanolSolventHCID 962WaterSolventHCID 8857Ethyl AcetateSolvent

Procedure

To 7 ml of anhydrous ethanol were added 510 mg of N-benzyl-4-oxocyclohexane-1,2-dicarboximide, 490 mg of concentrated sulfuric acid and 220 mg of phenylhydrazine. The mixture was refluxed for 2 hours and then cooled to room temperature. Thereto were added 30 ml of ethyl acetate and 20 ml of water. The resulting mixture was adjusted to pH 7.5 with an aqueous saturated sodium hydrogencarbonate solution. The organic layer was separated, washed with an aqueous saturated sodium chloride solution, and dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure. The residue was purified by column chromatography (eluant: benzene/ethyl acetate =50/1 to 20/1) to obtain two fractions. The first obtained fraction was concentrated to dryness under reduced pressure, and the residue was recrystallized from isopropyl alcohol to obtain 190 mg (yield: 29%) of N-benzyl-1,2,3,4-tetrahydrocarbazole-3,4-dicarboximide as colorless needles. The later obtained fraction was concentrated to dryness under reduced pressure to remove the solvent, and the residue was recrystallized from isopropyl alcohol to obtain 120 mg (yield: 18%) of N-benzyl-1,2,3,4-tetrahydrocarbazole-2,3-dicarboximide as colorless needles.

Workup

  1. temperatureThe mixture was refluxed for 2 hours
  2. customThe organic layer was separated
  3. washwashed with an aqueous saturated sodium chloride solution
  4. dry with materialdried over anhydrous magnesium sulfate
  5. customThe solvent was removed by distillation under reduced pressure
  6. customThe residue was purified by column chromatography (eluant: benzene/ethyl acetate =50/1 to 20/1)
  7. customto obtain two fractions
  8. concentrationThe first obtained fraction was concentrated to dryness under reduced pressure
  9. customthe residue was recrystallized from isopropyl alcohol

Sources & evidence

ORD record
ord-74fe7bd1939b4d4eacfbead4f4f671f3
Source dataset
uspto-grants-1992_11
Patent number
US05166204

Reaction notes

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