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

HRID 1670302Notes

Reaction equation

HRID 1670302 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-811dc588c8994990bfb39ac571eaa7a2
Source dataset
uspto-grants-2011_08
Patent number
US07989477B2

Reaction notes

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