Acetic Acid → 1-(1-Ethyl-4-hydroxy-5-methyl-1H-pyrazol-3-yl)ethan-1-one

HRID 1880330Notes

Reaction equation

HRID 1880330 reaction equation
[CH3:1][C:2]([CH:4]=O)=[O:3].[C:6]([OH:11])(=O)[C:7](O)=O.[CH2:12]([NH:14][NH2:15])[CH3:13].[C:16](O)(=O)C>O>[CH2:12]([N:14]1[C:7]([CH3:16])=[C:6]([OH:11])[C:4]([C:2](=[O:3])[CH3:1])=[N:15]1)[CH3:13]

Participants

5

Reactant 3

HCID 176Acetic AcidHCID 880MethylglyoxalHCID 96181Hydrazine, ethyl-, ethanedioate (1:1)

Product 1

HCID 534402521-(1-Ethyl-4-hydroxy-5-methyl-1H-pyrazol-3-yl)ethan-1-oneYield 56%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

An aqueous solution of methyl glyoxal (pyruvaldehyde) (40%, 6.5 mL, 40 mmol) was added to a solution of ethylhydrazine oxalate (1 g, 6.7 mmol) and acetic acid (0.57 mL, 10 mmol) in water (11 mL), and the resulting mixture was heated at reflux for 3 hours. The reaction mixture was cooled to room temperature and extracted with EtOAc (3×). The combined organic layers were dried, filtered, and concentrated under reduced pressure. The crude product was purified by flash chromatography (silica gel) eluting with a gradient of heptane to heptane:ethyl acetate (80:20) to give 622 mg (56%) of 1-(1-ethyl-4-hydroxy-5-methyl-1H-pyrazol-3-yl)ethanone as a white solid.

Workup

  1. temperaturethe resulting mixture was heated
  2. temperatureat reflux for 3 hours
  3. extractionextracted with EtOAc (3×)
  4. customThe combined organic layers were dried
  5. filtrationfiltered
  6. concentrationconcentrated under reduced pressure
  7. customThe crude product was purified by flash chromatography (silica gel)
  8. washeluting with a gradient of heptane to heptane:ethyl acetate (80:20)

Sources & evidence

ORD record
ord-1a8b0048c53c4b208fb121e42315d3de
Source dataset
uspto-grants-2012_11
Patent number
US08318762B2

Reaction notes

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