Phosphorus oxychloride → Triethyl 6-chloro-2,3,5-pyridinetricarboxylate

HRID 1733840

Reaction equation

HRID 1733840 reaction equation
O=[C:2]1[NH:7][C:6]([C:8]([O:10][CH2:11][CH3:12])=[O:9])=[C:5]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH:4]=[C:3]1[C:18]([O:20][CH2:21][CH3:22])=[O:19].P(Cl)(Cl)([Cl:25])=O>CN(C)C=O>[Cl:25][C:2]1[N:7]=[C:6]([C:8]([O:10][CH2:11][CH3:12])=[O:9])[C:5]([C:13]([O:15][CH2:16][CH3:17])=[O:14])=[CH:4][C:3]=1[C:18]([O:20][CH2:21][CH3:22])=[O:19]

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 19958207Triethyl 1,6-dihydro-6-oxo-2,3,5-pyridinetricarboxylate

Product 1

HCID 19958209Triethyl 6-chloro-2,3,5-pyridinetricarboxylateYield 47%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

A solution of triethyl 1,6-dihydro-6-oxo-2,3,5-pyridine-tricarboxylate (39.7 g) in 300 mL of phosphorous oxychloride and 0.5 mL dimethylformamid e is stirred at 100° C. for four hours and 15 minutes. After cooling, the excess phosphorous oxychloride is removed under vacuum. The residue is taken up in 200 mL methylene chloride and the solution poured into 500 mL of ice water and the layers are separated. The aqueous layer, made basic with concentrated ammonium hydroxide and ice, is extracted with 150 mL methylene chloride. The combined methylene chloride extracts are dried over magnesium sulfate, filtered and concentrated under vacuum, and the resulting crude product is chromatogra phed on silica using 5:1 hexanes:ethyl acetate and then 4:1 hexanes:ethyl acetate as eluants affording 26.5 g (47%) of the title product as an oil.

Workup

  1. temperatureAfter cooling
  2. customthe excess phosphorous oxychloride is removed under vacuum
  3. additionthe solution poured into 500 mL of ice water
  4. customthe layers are separated
  5. extractionis extracted with 150 mL methylene chloride
  6. dry with materialThe combined methylene chloride extracts are dried over magnesium sulfate
  7. filtrationfiltered
  8. concentrationconcentrated under vacuum

Sources & evidence

ORD record
ord-9dff64f7816a44f5823c077e952a61bb
Source dataset
uspto-grants-1996_07
Patent number
US05532207

Linked notes

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