Hydrochloric Acid → Methyl 2,3-dihydro-1H-indole-7-carboxylate

HRID 568792Notes

Reaction equation

HRID 568792 reaction equation
[CH3:1][O:2][C:3]([C:5]1[CH:6]=[CH:7][CH:8]=[C:9]2[C:13]=1[NH:12][CH:11]=[CH:10]2)=[O:4].[B-][N+](C)(C)C.Cl.[OH-].[Na+]>O1CCOCC1.CCOCC.O>[CH3:1][O:2][C:3]([C:5]1[CH:6]=[CH:7][CH:8]=[C:9]2[C:13]=1[NH:12][CH2:11][CH2:10]2)=[O:4]

Participants

8

Reactant 4

HCID 313Hydrochloric Acid2×HCID 14798Sodium HydroxideHCID 676694Methyl indole-7-carboxylateHCID 6327651Borane,N-dimethylmethanamine (1:1)

Product 1

HCID 14072919Methyl 2,3-dihydro-1H-indole-7-carboxylateYield 71.2%

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 3283Diethyl EtherSolventHCID 312751,4-DioxaneSolvent

Procedure

1.75 g of indole-7-carboxylic acid methyl ester and 2.92 g of borane-trimethylamine complex are dissolved in 10 ml of dioxane. To the resulting solution, 2 ml of concentrated hydrochloric acid are added. The reaction solution is heated under reflux for 30 minutes, and then cooled to room temperature. 10 ml of 6N hydrochloric acid are added to the reaction solution, which is then refluxed under heating for 15 minutes, and thereafter cooled to room temperature. The reaction solution is poured into 50 ml of water. The resulting mixture is neutralized with a 2N aqueous sodium hydroxide solution, and then extractd with ether. The organic layer is washed with a saturated aqueous sodium chloride solution, and dried over anhydrous sodium sulfate. After the solvent has been distilled off, 1.26 g of 2,3-dihydroindole-7-carboxylic acid methyl ester are obtained, mp. 70° to 73° C.

Workup

  1. temperatureThe reaction solution is heated
  2. temperatureunder reflux for 30 minutes
  3. temperatureis then refluxed
  4. temperatureunder heating for 15 minutes
  5. temperaturecooled to room temperature
  6. washThe organic layer is washed with a saturated aqueous sodium chloride solution
  7. dry with materialdried over anhydrous sodium sulfate
  8. distillationAfter the solvent has been distilled off

Sources & evidence

ORD record
ord-6e4da85376484ebdb25a60f35da2ad1d
Source dataset
uspto-grants-1988_03
Patent number
US04729998

Reaction notes

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