Ethyl 2,4-dioxovalerate → 1-Benzyl-5-methyl-1h-pyrazole-3-carboxylate

HRID 2374051Notes

Reaction equation

HRID 2374051 reaction equation
Cl.Cl.[CH2:3]([NH:10][NH2:11])[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1.CCN(C(C)C)C(C)C.O=[C:22]([CH2:28][C:29](=O)[CH3:30])[C:23]([O:25]CC)=[O:24]>CCO>[CH2:3]([N:10]1[C:29]([CH3:30])=[CH:28][C:22]([C:23]([OH:25])=[O:24])=[N:11]1)[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1

Participants

5

Reactant 3

HCID 69208Ethyl 2,4-dioxovalerateHCID 81531DiisopropylethylamineHCID 146540Benzylhydrazine dihydrochloride

Product 1

HCID 103760031-Benzyl-5-methyl-1h-pyrazole-3-carboxylateYield 92.5%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

To a solution of 1-benzylhydrazine dihydrochloride (Aldrich, 0.98 g, 5.0 mmol) in EtOH (30 mL) were added DIEA (2.0 mL) and ethyl 2,4-dioxopentanoate (0.70 mL, 5.0 mmol). The mixture was stirred at room temperature for 12 h and was concentrated in vacuo. The residue was dissolved in 1 N NaOH (10 mL). The solution was heated at 60° C. for 1 h. After cooling down, the solution was extracted with DCM (3×50 mL). The aqueous layer was neutralized to pH 2.0 and then was extracted with EtOAc. The organic layer was washed with brine and dried over MgSO4. It was filtered and concentrated to give 1-benzyl-5-methyl-1H-pyrazole-3-carboxylic acid (1.0 g, 92% yield). MS(ESI+): m/z 217.12 (M+H)+.

Workup

  1. concentrationwas concentrated in vacuo
  2. dissolutionThe residue was dissolved in 1 N NaOH (10 mL)
  3. temperatureThe solution was heated at 60° C. for 1 h
  4. temperatureAfter cooling down
  5. extractionthe solution was extracted with DCM (3×50 mL)
  6. extractionwas extracted with EtOAc
  7. washThe organic layer was washed with brine
  8. dry with materialdried over MgSO4
  9. filtrationIt was filtered
  10. concentrationconcentrated

Sources & evidence

ORD record
ord-a5a56a32c4534c30a47c0cdffe285bcb
Source dataset
uspto-grants-2008_12
Patent number
US07459562B2

Reaction notes

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