Hydrochloric Acid → Tryptophol

HRID 461386Notes

Reaction equation

HRID 461386 reaction equation
[NH:1]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[C:3]([C:10](=O)[C:11](OC(C)C)=[O:12])=[CH:2]1.[BH4-].[Li+].Cl>C(O)(C)C.O>[OH:12][CH2:11][CH2:10][C:3]1[C:4]2[C:9](=[CH:8][CH:7]=[CH:6][CH:5]=2)[NH:1][CH:2]=1

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 4148881Lithium borohydrideHCID 10398999HCID 10398999, compound

Product 1

HCID 10685Tryptophol

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 3776IsopropanolSolvent

Procedure

To a stirred suspension of isopropyl 3-indolylglyoxylate (46.4 g.) in isopropanol (500 ml.), lithium borohydride (13.1 g.) was added in small portions. The resulting solution was heated to reflux and stirred for 5 hours then cooled and diluted with water (2 l.). The mixture was acidified with hydrochloric acid and the product extracted into dichloromethane. The extract was washed with sodium carbonate solution then with water and the solvent was evaporated under reduced pressure to give an oil which was crystallised from toluene (50 ml.). The crude product was a red-brown powder, yield 25.0 g. (78%). This was distilled at 0.5 - 1mm. pressure and the distillate crystallised from toluene (100 ml.), giving 3-(2-hydroxyethyl)indole as white crystals, mp. 57°-59°. Yield 20.7g(64.5%)

Workup

  1. additionwas added in small portions
  2. temperatureThe resulting solution was heated
  3. temperatureto reflux
  4. temperaturethen cooled
  5. extractionthe product extracted into dichloromethane
  6. washThe extract was washed with sodium carbonate solution
  7. customwith water and the solvent was evaporated under reduced pressure
  8. customto give an oil which
  9. customwas crystallised from toluene (50 ml.)
  10. distillationThis was distilled at 0.5 - 1mm
  11. custompressure and the distillate crystallised from toluene (100 ml.)

Sources & evidence

ORD record
ord-b829cfdfa1ff4073b487bd48b8c2bbf8
Source dataset
uspto-grants-1977_12
Patent number
US04062869

Reaction notes

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