5-Methoxyindole → 5-methoxy-2,3-dihydro-1H-indole

HRID 1740771Notes

Reaction equation

HRID 1740771 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:9](=[CH:10][CH:11]=1)[NH:8][CH:7]=[CH:6]2.C([BH3-])#N.[Na+].[H][H].[OH-].[Na+]>C(O)(=O)C.O>[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:9](=[CH:10][CH:11]=1)[NH:8][CH2:7][CH2:6]2

Participants

7

Reactant 4

HCID 138725-MethoxyindoleHCID 14798Sodium HydroxideHCID 5003444Sodium cyanoborohydrideHCID 178418361HCID 178418361, compound

Product 1

HCID 107019745-methoxy-2,3-dihydro-1H-indole

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 962WaterSolvent

Procedure

To a solution of 50.0 g (340 mmol) of 5-methoxyindole in 700 ml of glacial acetic acid are added portionwise, at 15-20° C., 53.4 g (850 mmol) of sodium cyanoborohydride. The weakly exothermic addition is carried out over 3 hours and is accompanied by a slight evolution of hydrogen. The mixture is left stirring below 20° C. for 12 hours, 700 ml of water are then added and the pH of the reaction medium is adjusted to between 10 and 12 by addition of 1200 ml of 30% sodium hydroxide solution. The mixture is extracted twice with dichloromethane and the organic phase is then washed with 300 ml of water. The mixture is evaporated and the residue is purified by flash chromatography on a column of silica, the eluent used being a mixture of increasing polarity of methanol in dichloromethane. 41.84 g of colorless oil which becomes pale yellow on storage (to be stored under nitrogen atmosphere and sheltered from the light) are obtained.

Workup

  1. additionThe weakly exothermic addition
  2. waitThe mixture is left
  3. extractionThe mixture is extracted twice with dichloromethane
  4. washthe organic phase is then washed with 300 ml of water
  5. customThe mixture is evaporated
  6. customthe residue is purified by flash chromatography on a column of silica
  7. additiona mixture
  8. temperatureof increasing polarity of methanol in dichloromethane
  9. customare obtained

Sources & evidence

ORD record
ord-99b9923450ea44f0803b3581a52b773d
Source dataset
uspto-grants-1999_10
Patent number
US05972927

Reaction notes

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