Sulfuric Acid → Diethyl 1,2,3,4-tetrahydrocarbazole-2,3-dicarboxylate

HRID 373990Notes

Reaction equation

HRID 373990 reaction equation
O=[C:2]1[CH2:7][CH2:6][CH:5]([C:8]([O:10][CH2:11][CH3:12])=[O:9])[CH:4]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH2:3]1.S(=O)(=O)(O)O.[C:23]1([NH:29]N)[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=1.C(=O)([O-])O.[Na+]>O.C(OCC)(=O)C.C(O)C>[CH2:6]1[C:7]2[NH:29][C:23]3[C:24](=[CH:25][CH:26]=[CH:27][CH:28]=3)[C:2]=2[CH2:3][CH:4]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH:5]1[C:8]([O:10][CH2:11][CH3:12])=[O:9]

Participants

8

Reactant 4

HCID 1118Sulfuric AcidHCID 7516PhenylhydrazineHCID 516892Sodium BicarbonateHCID 14062941Diethyl 4-oxocyclohexane-1,2-dicarboxylate

Product 1

HCID 19808697Diethyl 1,2,3,4-tetrahydrocarbazole-2,3-dicarboxylateYield 59.4%

Reagents, catalysts & solvents 3

HCID 702EthanolSolventHCID 962WaterSolventHCID 8857Ethyl AcetateSolvent

Procedure

To 20 ml of ethanol were added 2.66 g of diethyl 4-oxocyclohexane-1,2-dicarboxylate, 2.45 g of concentrated sulfuric acid and 1.08 g of phenylhydrazine. The mixture was refluxed for 2 hours and then cooled to room temperature. Thereto were added 50 ml of ethyl acetate and 50 ml of water. The 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 recrystallized from ethanol to obtain 1.87 g (yield: 59%) of diethyl 1,2,3,4-tetrahydrocarbazole-2,3-dicarboxylate 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 recrystallized from ethanol

Sources & evidence

ORD record
ord-754ae980b0c441478053da60818f18c9
Source dataset
uspto-grants-1992_11
Patent number
US05166204

Reaction notes

Loading…