Hydrazine → ethyl 5-(2-methylpropyl)-1H-pyrazole-3-carboxylate

HRID 1984323Notes

Reaction equation

HRID 1984323 reaction equation
[NH2:1][NH2:2].[CH3:3][CH:4]([CH3:16])[CH2:5][C:6](=O)[CH2:7][C:8](=O)[C:9]([O:11][CH2:12][CH3:13])=[O:10].[Na]>C(O)(=O)C>[CH3:3][CH:4]([CH3:16])[CH2:5][C:6]1[NH:2][N:1]=[C:8]([C:9]([O:11][CH2:12][CH3:13])=[O:10])[CH:7]=1

Participants

5

Reactant 3

HCID 9321HydrazineHCID 3006751ethyl 6-methyl-2,4-dioxoheptanoateHCID 5360545Sodium

Product 1

HCID 3804408ethyl 5-(2-methylpropyl)-1H-pyrazole-3-carboxylate

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

Anhydrous hydrazine (3.58 g, 112 mmol) was added dropwise over a period of 30 minutes to a solution of ethyl 6-methyl-2,4-dioxoheptanoate, sodium salt (24.8 g, 112 mmol) in acetic acid (160 mL). The reaction was stirred overnight at ambient temperature, and then the solvent was removed under reduced pressure. The residue was dissolved in a mixture of diethyl ether and water, and solid sodium bicarbonate and sodium carbonate were added to adjust the mixture to pH 8. The aqueous layer was extracted twice with diethyl ether; the combined organic fractions were washed with brine, dried over magnesium sulfate, filtered, and concentrated under reduced pressure. The residue was purified by chromatography on a HORIZON HPFC system (FLASH 65I cartridge, eluting with 50:50 ethyl acetate/hexanes) to provide 21.0 g of ethyl 5-(2-methylpropyl)-1H-pyrazole-3-carboxylate as a solid.

Workup

  1. customthe solvent was removed under reduced pressure
  2. dissolutionThe residue was dissolved in a mixture of diethyl ether and water, and solid sodium bicarbonate and sodium carbonate
  3. additionwere added
  4. extractionThe aqueous layer was extracted twice with diethyl ether
  5. washthe combined organic fractions were washed with brine
  6. dry with materialdried over magnesium sulfate
  7. filtrationfiltered
  8. concentrationconcentrated under reduced pressure
  9. customThe residue was purified by chromatography on a HORIZON HPFC system (FLASH 65I cartridge, eluting with 50:50 ethyl acetate/hexanes)

Sources & evidence

ORD record
ord-cc70c1a0025e4c58ae5ec82ff91ffbfd
Source dataset
uspto-grants-2009_06
Patent number
US07544697B2

Reaction notes

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