Hydrochloric Acid → 9-Acetylcarbazole-3,4-dicarboxylic anhydride

HRID 373989Notes

Reaction equation

HRID 373989 reaction equation
C(N1C(=O)C2[C:22]3[C:21]4[C:16](=[CH:17][CH:18]=[CH:19][CH:20]=4)[NH:15][C:14]=3[CH:13]=[CH:12]C=2C1=O)C1C=CC=CC=1.[O:26]1CCO[CH2:28][CH2:27]1.[OH-:32].[Na+].Cl.[C:35]([O:38][CH2:39][CH3:40])(=[O:37])[CH3:36]>O>[C:27]([N:15]1[C:14]2[CH:13]=[CH:12][C:36]3[C:35]([O:38][C:39](=[O:32])[C:40]=3[C:22]=2[C:21]2[C:16]1=[CH:17][CH:18]=[CH:19][CH:20]=2)=[O:37])(=[O:26])[CH3:28]

Participants

7

Reactant 5

HCID 313Hydrochloric AcidHCID 8857Ethyl AcetateHCID 14798Sodium HydroxideHCID 312751,4-DioxaneHCID 19808688N-benzylcarbazole-3,4-dicarboximide

Product 1

HCID 183667359-Acetylcarbazole-3,4-dicarboxylic anhydrideYield 78%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

To 330 mg of N-benzyl carbazole-3,4-dicarboximide were added 5 ml of dioxane and 1.0 ml of a 5 N aqueous sodium hydroxide solution. The mixture was refluxed for 30 minutes. Thereto was added 3.0 ml of concentrated hydrochloric acid. The resulting 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 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. To the residue was added 3.0 ml of acetic anhydride, and the mixture was refluxed for 30 minutes and then cooled to room temperature. The precipitated crystals were collected by filtration and washed with diethyl ether to obtain 220 mg (yield: 78%) of 9-acetylcarbazole-3,4-dicarboxylic anhydride as light yellow crystals.

Workup

  1. temperatureThe mixture was refluxed for 30 minutes
  2. temperatureThe resulting mixture was refluxed for 2 hours
  3. customThe organic layer was separated
  4. washwashed with an aqueous saturated sodium chloride solution
  5. dry with materialdried over anhydrous magnesium sulfate
  6. customThe solvent was removed by distillation under reduced pressure
  7. additionTo the residue was added 3.0 ml of acetic anhydride
  8. temperaturethe mixture was refluxed for 30 minutes
  9. temperaturecooled to room temperature
  10. filtrationThe precipitated crystals were collected by filtration
  11. washwashed with diethyl ether

Sources & evidence

ORD record
ord-078ff7364b944d1eb1d4aed26a851615
Source dataset
uspto-grants-1992_11
Patent number
US05166204

Reaction notes

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