Phosphorus oxychloride → 4-Chloro-1,2,5-trimethyl-6-oxo-1,6-dihydropyridine-3-carboxylic acid ethyl ester

HRID 15930Notes

Reaction equation

HRID 15930 reaction equation
P(Cl)(Cl)([Cl:3])=O.[CH2:6]([O:8][C:9]([C:11]1[C:16](O)=[C:15]([CH3:18])[C:14](=[O:19])[N:13]([CH3:20])[C:12]=1[CH3:21])=[O:10])[CH3:7]>>[CH2:6]([O:8][C:9]([C:11]1[C:16]([Cl:3])=[C:15]([CH3:18])[C:14](=[O:19])[N:13]([CH3:20])[C:12]=1[CH3:21])=[O:10])[CH3:7]

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 66673467Ethyl 4-hydroxy-1,2,5-trimethyl-6-oxo-1,6-dihydropyridine-3-carboxylate

Product 1

HCID 666739724-Chloro-1,2,5-trimethyl-6-oxo-1,6-dihydropyridine-3-carboxylic acid ethyl esterYield 89%

Conditions

Temperature
80 °C

Procedure

Phosphorous oxychloride (20.0 mL, 216 mmol) was added to 4-hydroxy-1,2,5-trimethyl-6-oxo-1,6-dihydropyridine-3-carboxylic acid ethyl ester and heated to 80° C. After two hours, the reaction mixture was concentrated under reduced pressure. The resulting residue was poured onto ice and, carefully neutralized with saturated NaHCO3, and diluted with EtOAc. After stirring for 16 hours, the organic layer was separated and the aqueous layer was reextracted with EtOAc repeatedly. The pH of the aqueous layer was adjusted to pH 11 with saturated K2CO3 and extracted with EtOAc (2×). The combined organic extracts were dried (MgSO4) and concentrated under reduced pressure to give 3.42 g (89%) clean desired product.

Workup

  1. concentrationthe reaction mixture was concentrated under reduced pressure
  2. additionThe resulting residue was poured onto ice
  3. additiondiluted with EtOAc
  4. customthe organic layer was separated
  5. extractionextracted with EtOAc (2×)
  6. dry with materialThe combined organic extracts were dried (MgSO4)
  7. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-7683030ccf3a44bd83ce9b6ff57213f2
Source dataset
uspto-grants-2010_06
Patent number
US07732616B2

Reaction notes

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