Isopropanol → Tryptophol

Participants

Reaction Steps

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).

Provenance & Evidence