Hydrochloric Acid → 4-methoxy-2,3-dihydro-1H-indole

HRID 430779Notes

Reaction equation

HRID 430779 reaction equation
[B-][N+](C)(C)C.Cl.[CH3:7][O:8][C:9]1[CH:17]=[CH:16][CH:15]=[C:14]2[C:10]=1[CH:11]=[CH:12][NH:13]2>O1CCOCC1>[CH3:7][O:8][C:9]1[CH:17]=[CH:16][CH:15]=[C:14]2[C:10]=1[CH2:11][CH2:12][NH:13]2

Participants

5

Reactant 3

HCID 313Hydrochloric Acid2×HCID 1383634-Methoxy-1H-indoleHCID 6327651Borane,N-dimethylmethanamine (1:1)

Product 1

HCID 162444414-methoxy-2,3-dihydro-1H-indoleYield 83%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

Borane-trimethylamine complex (3.00 g) and 10.5N hydrochloric acid (2.25 ml) were added to 4-methoxyindole (1.29 g) in dioxane (20 ml), and the mixture was heated to reflux for 30 minutes. To this mixture, 6N hydrochloric acid (7.00 ml) was added and the mixture was heated to reflux for 15 minutes. The solvent was removed under reduced pressure and 1N aqueous sodium hydroxide solution was added to change the aqueous layer to alkaline condition, followed by extracting the aqueous layer with ether (3×20 ml). The obtained organic layers were washed with saturated brine and dried over sodium sulfate. After removing solids by filtration, the solvent was removed under reduced pressure, and the obtained crude product was purified by silica gel column chromatography to obtain the desired compound (1.08 g, yield: 83%).

Workup

  1. temperaturethe mixture was heated
  2. temperatureto reflux for 30 minutes
  3. temperaturethe mixture was heated
  4. temperatureto reflux for 15 minutes
  5. customThe solvent was removed under reduced pressure and 1N aqueous sodium hydroxide solution
  6. additionwas added
  7. extractionby extracting the aqueous layer with ether (3×20 ml)
  8. washThe obtained organic layers were washed with saturated brine
  9. dry with materialdried over sodium sulfate
  10. customAfter removing solids
  11. filtrationby filtration
  12. customthe solvent was removed under reduced pressure
  13. customthe obtained crude product
  14. customwas purified by silica gel column chromatography

Sources & evidence

ORD record
ord-cc3004f1dd034e4c8e56fa2c8decc2a1
Source dataset
uspto-grants-2001_11
Patent number
US06323235B1

Reaction notes

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