Acetic Anhydride → 1H-Imidazo[1,2-b]pyrazole-1-carbaldehyde

HRID 1463978Notes

Reaction equation

HRID 1463978 reaction equation
C(O[C:5](=[O:7])C)(=O)C.[NH:8]1[C:15]2[N:11]([N:12]=[CH:13][CH:14]=2)[CH:10]=[CH:9]1>C(O)=O>[CH:5]([N:8]1[C:15]2[N:11]([N:12]=[CH:13][CH:14]=2)[CH:10]=[CH:9]1)=[O:7]

Participants

4

Reactant 2

HCID 7918Acetic AnhydrideHCID 178419859HCID 178419859, compound

Product 1

HCID 190891101H-Imidazo[1,2-b]pyrazole-1-carbaldehyde

Reagents, catalysts & solvents 1

HCID 284Formic AcidSolvent

Procedure

A mixture of acetic anhydride (3.68 ml) and formic acid (3 ml) was stirred at room temperature for 1 hour. The solution was cooled in an ice-bath and 1H-imidazo-[1,2-b]pyrazole (2.1 g) was added thereto. The mixture was stirred at room temperature for 1 hour. The reaction mixture was evaporated and the residue was subjected to column chromatography on silica gel using a mixture of n-hexane and ethyl acetate (1:1) as an eluent. Fractions containing the object compound were combined and the solvent was evaporated to give 1-formyl-1H-imidazo[1,2-b]pyrazole (1.83 g). NMR (DMSO-d6, δ) : 6.20 and 6.28 (total 1H, each d, J=2Hz), 7.65-7.72 (1H, m), 7.71 (1H, d, J=2Hz), 7.87-7.92 (1H, m), 9.02 (1H, br s)

Workup

  1. temperatureThe solution was cooled in an ice-bath
  2. stirringThe mixture was stirred at room temperature for 1 hour
  3. customThe reaction mixture was evaporated
  4. additiona mixture of n-hexane and ethyl acetate (1:1) as an eluent
  5. additionFractions containing the object compound
  6. customthe solvent was evaporated

Sources & evidence

ORD record
ord-357254dcf9da41658840d002b6730c2d
Source dataset
uspto-grants-1994_04
Patent number
US05302712

Reaction notes

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