5-Methylindole → 5-Methylindoline

HRID 1459037Notes

Reaction equation

HRID 1459037 reaction equation
C([BH3-])#N.[Na+].[CH3:5][C:6]1[CH:7]=[C:8]2[C:12](=[CH:13][CH:14]=1)[NH:11][CH:10]=[CH:9]2.[H][H].[OH-].[Na+]>C(O)(=O)C.O>[CH3:5][C:6]1[CH:7]=[C:8]2[C:12](=[CH:13][CH:14]=1)[NH:11][CH2:10][CH2:9]2

Participants

7

Reactant 4

HCID 119785-MethylindoleHCID 14798Sodium HydroxideHCID 5003444Sodium cyanoborohydrideHCID 178418361HCID 178418361, compound

Product 1

HCID 140236795-MethylindolineYield 75%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 962WaterSolvent

Procedure

28.74 g (457 mmol) of sodium cyanoborohydride are added in small portions at below 20° C. to a solution of 20.0 g (152 mmol) of 5-methylindole in 300 ml of glacial acetic acid. The addition, which is slightly exothermic, is made over 3 hours and is accompanied by slight evolution of hydrogen. The mixture is stirred for 12 hours at below 20° C., and then 300 ml of water are added and the pH of the reaction medium is adjusted to between 10 and 12 by addition of 500 ml of 30% sodium hydroxide solution. The mixture is extracted twice with dichloromethane and the organic phase is washed with 100 ml of water. It is evaporated and the residue is purified by flash chromatography on a silica column, the eluent used being a mixture of increasing polarity of methanol in methylene chloride. 15.3 g (yield=75%) are obtained of a colourless oil which develops a brown colour on storage (under a nitrogen atmosphere with the exclusion of light).

Workup

  1. additionThe addition, which
  2. extractionThe mixture is extracted twice with dichloromethane
  3. washthe organic phase is washed with 100 ml of water
  4. customIt is evaporated
  5. customthe residue is purified by flash chromatography on a silica column
  6. additiona mixture
  7. temperatureof increasing polarity of methanol in methylene chloride
  8. custom15.3 g (yield=75%) are obtained of a colourless oil which

Sources & evidence

ORD record
ord-898642d5d52047ed958ff1f7b1574bef
Source dataset
uspto-grants-1998_12
Patent number
US05852190

Reaction notes

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