Isopropanol → Tryptophol

HRID 461385Notes

Reaction equation

HRID 461385 reaction equation
C(O)(C)C.[NH:5]1[C:13]2[C:8](=[CH:9][CH:10]=[CH:11][CH:12]=2)[C:7]([C:14](=O)[C:15](OC)=[O:16])=[CH:6]1.[BH4-].[Na+]>O>[OH:16][CH2:15][CH2:14][C:7]1[C:8]2[C:13](=[CH:12][CH:11]=[CH:10][CH:9]=2)[NH:5][CH:6]=1

Participants

5

Reactant 3

HCID 3776IsopropanolHCID 588944Methyl 3-indoleglyoxylateHCID 4311764Sodium borohydride

Product 1

HCID 10685Tryptophol

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A vigorously-stirred mixture of isopropanol (3 1), methyl 3- indolylglyoxylate (305 g) and sodium borohydride (125 g) was warmed to 40° - 50° and held at that temperature until the initial exothermic reaction was complete. The mixture was then heated to reflux for 4 hours, cooled and diluted with water (5 l). After acidification with hydrochloric acid the product was extracted into dichloromethane. The separated extract was washed with sodium carbonate solution to remove 3-indolylacetic acid and then with water. Evaporation of the solvent gave the crude product as a brown oil. This was distilled at 0.5 - 1 mm pressure (vapour temperature 160° - 190° ) and crystallised from toluene (1 l) to give the title compound as white to pale brown crystals m.p. 57° - 59°. Yield 170 g. (70% of theory).

Workup

  1. temperaturewas warmed to 40° - 50°
  2. customexothermic reaction
  3. temperatureThe mixture was then heated
  4. temperatureto reflux for 4 hours
  5. temperaturecooled
  6. extractionAfter acidification with hydrochloric acid the product was extracted into dichloromethane
  7. extractionThe separated extract
  8. washwas washed with sodium carbonate solution
  9. customto remove 3-indolylacetic acid
  10. customEvaporation of the solvent
  11. customgave the crude product as a brown oil
  12. distillationThis was distilled at 0.5 - 1 mm pressure (vapour temperature 160° - 190° )
  13. customcrystallised from toluene (1 l)

Sources & evidence

ORD record
ord-f5d20c936e754c38bea4229c1dafed5c
Source dataset
uspto-grants-1977_12
Patent number
US04062869

Reaction notes

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