Sulfuric Acid → Ethyl 2-(3-chloro-2-pyridinyl)-2,5-dihydro-5-oxo-1H-pyrazole-3-carboxylate

HRID 475469

反応式

HRID 475469 の反応式
[Cl:1][C:2]1[C:3]([N:8]2[CH:12]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH2:11][C:10](=[O:18])[NH:9]2)=[N:4][CH:5]=[CH:6][CH:7]=1.S(=O)(=O)(O)O.S(OOS([O-])(=O)=O)([O-])(=O)=O.[K+].[K+]>C(#N)C>[Cl:1][C:2]1[C:3]([N:8]2[C:12]([C:13]([O:15][CH2:16][CH3:17])=[O:14])=[CH:11][C:10](=[O:18])[NH:9]2)=[N:4][CH:5]=[CH:6][CH:7]=1

参加物

5

反応物 3

HCID 1118Sulfuric AcidHCID 24412Potassium PersulfateHCID 22280352Ethyl 2-(3-Chloro-2-pyridinyl)-5-oxo-3-pyrazolidinecarboxylate

生成物 1

HCID 21113391Ethyl 2-(3-chloro-2-pyridinyl)-2,5-dihydro-5-oxo-1H-pyrazole-3-carboxylate収率 15.7%

試薬・触媒・溶媒 1

HCID 6342Acetonitrile溶媒

実験手順

To a suspension of ethyl 2-(3-chloro-2-pyridinyl)-5-oxo-3-pyrazolidinecarboxylate (i.e. product of Example 12, Step A) (27 g, 100 mmol) stirred in dry acetonitrile (200 mL) was added sulfuric acid (20 g, 200 mmol) in one portion. The reaction mixture thinned to form a pale green, nearly clear solution before thickening again to form a pale yellow suspension. Potassium persulfate (33 g, 120 mmol) was added in one portion, and then the reaction mixture was heated at gentle reflux for 3.5 hours. After cooling using an ice bath, a precipitate of white solid was removed by filtration and discarded. The filtrate was diluted with water (400 mL) and then extracted three times with ethyl ether (700 mL total). Concentration of the combined ether extracts to a reduced volume (75 mL) caused precipitation of an off-white solid (3.75 g), which was collected by filtration. The ether mother liquor was further concentrated to yield a second crop of an off-white precipitate (4.2 g), which was also collected by filtration. An off-white solid also precipitated from the aqueous phase; this solid (4.5 g) was collected by filtration to provide a combined total of 12.45 g of the title compound.

後処理

  1. customThe reaction mixture thinned to form a pale green, nearly clear solution
  2. customto form a pale yellow suspension
  3. temperaturethe reaction mixture was heated
  4. temperatureat gentle reflux for 3.5 hours
  5. temperatureAfter cooling
  6. customa precipitate of white solid was removed by filtration
  7. additionThe filtrate was diluted with water (400 mL)
  8. extractionextracted three times with ethyl ether (700 mL total)
  9. customprecipitation of an off-white solid (3.75 g), which
  10. filtrationwas collected by filtration
  11. concentrationThe ether mother liquor was further concentrated

出典と根拠

ORDレコード
ord-deef078599954c1fac16d9e6cd681935
出典データセット
uspto-grants-2014_01
特許番号
US08637552B2

関連ノート

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