Ethanol → Ethyl 5-chloropyridine-2-carboxylate 1-oxide

HRID 70530

反応式

HRID 70530 の反応式
S(=O)(=O)(O)O.[Cl:6][C:7]1[CH:8]=[CH:9][C:10]([C:13]([OH:15])=[O:14])=[N:11][CH:12]=1.[OH2:16].[CH2:17](O)[CH3:18]>>[Cl:6][C:7]1[CH:12]=[N+:11]([O-:16])[C:10]([C:13]([O:15][CH2:17][CH3:18])=[O:14])=[CH:9][CH:8]=1

参加物

5

反応物 4

HCID 702EthanolHCID 962WaterHCID 1118Sulfuric AcidHCID 27628725-Chloro-2-picolinic acid

生成物 1

HCID 67397297Ethyl 5-chloropyridine-2-carboxylate 1-oxide

実験手順

Concentrated sulfuric acid (4 mL) was added to a solution of 5-chloropyridine-2-carboxylic acid (25.3 g) in ethanol (500 mL) under ice-cooling, and the mixture was stirred under reflux for four hours. The reaction solution was cooled to room temperature and water was added, followed by extraction with chloroform. The organic layer was dried over anhydrous magnesium sulfate and filtered. The solvent was then evaporated under reduced pressure. The residue was purified by silica gel column chromatography (chloroform only→hexane:ethyl acetate=1:1) and the solvent was evaporated under reduced pressure from the fraction containing ethyl 5-chloropyridine-2-carboxylate. Urea peroxide (30.2 g) was added to a solution of the residue in chloroform (300 mL) under ice-cooling. A mixture of trifluoroacetic anhydride (44.7 mL) and chloroform (300 mL) was added dropwise over 30 minutes, and the mixture was stirred while gradually returning to room temperature for two hours. A saturated sodium thiosulfate solution was added dropwise to the reaction solution, followed by extraction with chloroform. The organic layer was dried over anhydrous magnesium sulfate and filtered. The solvent was then evaporated under reduced pressure. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=1:1) to give ethyl 5-chloropyridine-2-carboxylate 1-oxide as a yellow oil (36.8 g, quant.).

後処理

  1. temperaturecooling
  2. temperatureunder reflux for four hours
  3. extractionfollowed by extraction with chloroform
  4. dry with materialThe organic layer was dried over anhydrous magnesium sulfate
  5. filtrationfiltered
  6. customThe solvent was then evaporated under reduced pressure
  7. customThe residue was purified by silica gel column chromatography (chloroform only→hexane
  8. customethyl acetate=1:1) and the solvent was evaporated under reduced pressure from the fraction
  9. additioncontaining ethyl 5-chloropyridine-2-carboxylate
  10. additionUrea peroxide (30.2 g) was added to a solution of the residue in chloroform (300 mL) under ice-
  11. temperaturecooling
  12. additionA mixture of trifluoroacetic anhydride (44.7 mL) and chloroform (300 mL)
  13. additionwas added dropwise over 30 minutes
  14. stirringthe mixture was stirred
  15. additionA saturated sodium thiosulfate solution was added dropwise to the reaction solution
  16. extractionfollowed by extraction with chloroform
  17. dry with materialThe organic layer was dried over anhydrous magnesium sulfate
  18. filtrationfiltered
  19. customThe solvent was then evaporated under reduced pressure
  20. customThe residue was purified by silica gel column chromatography (hexane:ethyl acetate=1:1)

出典と根拠

ORDレコード
ord-8b9f3b0a55c040c6a4e792a8075ae462
出典データセット
uspto-grants-2014_09
特許番号
US08822503B2

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