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

HRID 1840931Notes

Reaction equation

HRID 1840931 reaction equation
[NH:1]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[CH:3]=[CH:2]1.[OH-].[K+].Cl.O.[NH:14]1[CH2:19][CH2:18][C:17](=O)[CH2:16][CH2:15]1>CO>[NH:14]1[CH2:15][CH:16]=[C:17]([C:3]2[C:4]3[C:9](=[CH:8][CH:7]=[CH:6][CH:5]=3)[NH:1][CH:2]=2)[CH2:18][CH2:19]1

Participants

5

Reactant 3

HCID 798IndoleHCID 14797Potassium HydroxideHCID 2723901Piperonylamine

Product 1

HCID 27610233-(1,2,3,6-Tetrahydropyridin-4-yl)-1H-indole

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

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.

Workup

  1. temperaturethe mixture was heated
  2. temperatureto reflux for 5 h
  3. customPotassium chloride precipitated
  4. filtrationthe salt was filtered
  5. concentrationThe liquid phase was concentrated until only one third of the liquid
  6. customThe solid formed during the concentration of the liquid phase
  7. filtrationwas filtered
  8. washwashed thoroughly with ethanol

Sources & evidence

ORD record
ord-7696003d63bc437289e2e01d78c4bf65
Source dataset
uspto-grants-2004_01
Patent number
US06683096B2

Reaction notes

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