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

HRID 457776Notes

Reaction equation

HRID 457776 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

30 g (0.26 mol) of indole 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 it was filtered off. 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 were obtained.

Workup

  1. temperaturethe mixture was heated
  2. temperatureto reflux for 5 h
  3. customPotassium chloride precipitated
  4. filtrationit was filtered off
  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-ad14c7810666438b81e14b060110f6b0
Source dataset
uspto-grants-2007_03
Patent number
US07189741B2

Reaction notes

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