Acetic Anhydride → 1-[2-(Propan-2-yl)pyrazolo[1,5-a]pyridin-3-yl]ethan-1-one

HRID 436805Notes

Reaction equation

HRID 436805 reaction equation
[CH:1]([C:4]1[CH:12]=[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][N:6]2[N:5]=1)([CH3:3])[CH3:2].[C:13](OC(=O)C)(=[O:15])[CH3:14]>S(=O)(=O)(O)O.[OH-].[K+]>[C:13]([C:12]1[C:4]([CH:1]([CH3:3])[CH3:2])=[N:5][N:6]2[CH:11]=[CH:10][CH:9]=[CH:8][C:7]=12)(=[O:15])[CH3:14]

Participants

5

Reactant 2

HCID 7918Acetic AnhydrideHCID 113786582-Isopropylpyrazolo[1,5-a]pyridine

Product 1

HCID 159338551-[2-(Propan-2-yl)pyrazolo[1,5-a]pyridin-3-yl]ethan-1-oneYield 81.1%

Reagents, catalysts & solvents 2

HCID 1118Sulfuric AcidCatalystHCID 14797Potassium HydroxideSolvent

Procedure

A mixture of 4.2g of 2-isopropylpyrazolo[1,5-a]pyridine, 10.2g of acetic anhydride and 2-3 drops of concentrated sulfuric acid was refluxed for 7 hr. After cooling, the mixture was added to 200 ml of 4M potassium hydroxide solution and stirred for 1 hr. The solution was extracted with chloroform and the chloroform solution was dried over sodium sulfate. The dried chloroform solution was concentrated and the residue was column-chromatographed over alumina to isolate objective product. Recrystallization from n-hexane gave 4.3g of colorless needles, mp 74° C. Yield 67%.

Workup

  1. temperaturewas refluxed for 7 hr
  2. temperatureAfter cooling
  3. extractionThe solution was extracted with chloroform
  4. dry with materialthe chloroform solution was dried over sodium sulfate
  5. concentrationThe dried chloroform solution was concentrated
  6. customthe residue was column-chromatographed over alumina
  7. customto isolate objective product
  8. customRecrystallization from n-hexane

Sources & evidence

ORD record
ord-e337613853a04d768982976cdd3ca353
Source dataset
uspto-grants-1977_06
Patent number
US04028370

Reaction notes

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