Indole → 3-(1,2,3,6-Tetrahydropyridin-4-yl)-1H-indole

Participants

Reaction Steps

Indole (30 g, 0.26 mol) was dissolved in a solution of potassium hydroxide (77.6 g, 1.38 mol) in methanol (692 ml). 4-piperidone monohydrate hydrochloride (102.3 g, 0.66 mol) was added in one portion and the mixture was heated to reflux for 5 h. Potassium chloride precipitated upon cooling at room temperature and the salt was filtered. The liquid phase was concentrated until only one third of the liquid remained in the round-bottom flask. The solid formed during the concentration of the liquid phase was filtered and washed thoroughly with ethanol and, finally, with ethyl ether. 31.9 g (63% of yield) of the final product was obtained.

Provenance & Evidence