2,5-Hexanedione → 5-Bromo-2-(2,5-dimethyl-1H-pyrrol-1-yl)pyridine

HRID 1831000Notes

Reaction equation

HRID 1831000 reaction equation
[CH3:1][C:2](=O)[CH2:3][CH2:4][C:5](=O)[CH3:6].[NH2:9][C:10]1[CH:15]=[CH:14][C:13]([Br:16])=[CH:12][N:11]=1>C1(C)C=CC(S(O)(=O)=O)=CC=1>[Br:16][C:13]1[CH:14]=[CH:15][C:10]([N:9]2[C:2]([CH3:1])=[CH:3][CH:4]=[C:5]2[CH3:6])=[N:11][CH:12]=1

Participants

4

Reactant 2

HCID 80352,5-HexanedioneHCID 706222-Amino-5-bromopyridine

Product 1

HCID 120436225-Bromo-2-(2,5-dimethyl-1H-pyrrol-1-yl)pyridineYield 74.7%

Reagents, catalysts & solvents 1

HCID 6101p-Toluenesulfonic acidCatalyst

Procedure

2,5-hexanedione (46.2 g, 0.41 mol) was added to a suspension of 2-amino-5-bromopyridine (50.0 g, 0.29 mol) and the reaction heated to reflux for 24 hours under Dean and Stark conditions. para-Toluene sulfonic acid (100 mg) was added and the reaction was refluxed for a further 18 hours. 8 ml of water were removed, so the reaction was cooled to room temperature, washed with water (100 ml) and passed through a plug of silica gel, eluting with toluene. The eluent was concentrated in vacuo and the residue dissolved in pentane:dichloromethane (1:1 by volume) and passed through a plug of silica gel, eluting with pentane:dichloromethane (1:1 by volume). The eluent was concentrated in vacuo to give a red liquid, which solidified on standing. The solid was recrystallised from isopropanol to give the title compound as a pale yellow solid (54.4 g).

Workup

  1. temperaturethe reaction heated
  2. temperatureto reflux for 24 hours under Dean and Stark conditions
  3. temperaturethe reaction was refluxed for a further 18 hours
  4. custom8 ml of water were removed
  5. washwashed with water (100 ml)
  6. washeluting with toluene
  7. concentrationThe eluent was concentrated in vacuo
  8. dissolutionthe residue dissolved in pentane:dichloromethane (1:1 by volume)
  9. washeluting with pentane:dichloromethane (1:1 by volume)
  10. concentrationThe eluent was concentrated in vacuo
  11. customto give a red liquid, which
  12. customThe solid was recrystallised from isopropanol

Sources & evidence

ORD record
ord-c4151767b5dc4613aac2ce05b1ef6c45
Source dataset
uspto-grants-2006_06
Patent number
US07067541B2

Reaction notes

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