Sodium Carbonate → 2-Chloro-4-pyridinecarboxaldehyde

HRID 1598771Notes

Reaction equation

HRID 1598771 reaction equation
[Cl:1][C:2]1[CH:7]=[C:6]([CH2:8][OH:9])[CH:5]=[CH:4][N:3]=1.C1C(=O)N(Br)C(=O)C1.C([O-])([O-])=O.[K+].[K+].C([O-])([O-])=O.[Na+].[Na+]>CCOC(C)=O>[Cl:1][C:2]1[CH:7]=[C:6]([CH:8]=[O:9])[CH:5]=[CH:4][N:3]=1

Participants

6

Reactant 4

HCID 10340Sodium CarbonateHCID 11430Potassium CarbonateHCID 67184N-bromobutanimide2×HCID 7062237(2-Chloropyridin-4-yl)methanol

Product 1

HCID 27629942-Chloro-4-pyridinecarboxaldehyde

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Procedure

A suspension of 2-chloro-4-pyridinemethanol (8.0 g, 55.9 mmol), NBS (14.9 g, 83.9 mmol), and K2CO3 (11.75 g, 97.1 mmol) in EtOAc was refluxed for 3 h. A second portion of NBS (14.9 g, 83.9 mmol) and Na2CO3 (12.0 g, 114 mmol) were added and the reaction was heated to reflux for an additional 3.5 h, cooled and filtered through a pad of celite. The filtrate, after concentration to a small volume, was subjected to flash chromatography eluting with 0.5-4% CH3OH/CH2Cl2. The fractions containing product were combined, washed successively with sat aq NaHCO3 10% Na2S2O3, and brine, dried (MgSO4) and concentrated in vacuo to give the title compound as a light yellow solid; yield 5.3 g (67%). 1H NMR,,(CDCl3) δ 10.06 (s, 1H), 8.66 (d, 1H, J=5.0 Hz), 7.76 (s, 1H), 7.66 (d, 1H, J=5.0 Hz).

Workup

  1. temperaturewas refluxed for 3 h
  2. temperaturethe reaction was heated
  3. temperatureto reflux for an additional 3.5 h
  4. temperaturecooled
  5. filtrationfiltered through a pad of celite
  6. concentrationThe filtrate, after concentration to a small volume
  7. washeluting with 0.5-4% CH3OH/CH2Cl2
  8. additionThe fractions containing product
  9. washwashed successively with sat aq NaHCO3 10% Na2S2O3, and brine
  10. dry with materialdried (MgSO4)
  11. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-171b7ade004d4e13bf7675eace72ab44
Source dataset
uspto-grants-1998_04
Patent number
US05739143

Reaction notes

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