Ethyl 2,4-dioxovalerate → Ethyl 1-ethyl-5-methyl-1H-pyrazole-3-carboxylate

HRID 1360441Notes

Reaction equation

HRID 1360441 reaction equation
C(O)(=O)C(O)=O.[CH2:7]([NH:9][NH2:10])[CH3:8].[CH3:11][CH2:12][O:13][C:14]([C:16]([CH2:18][C:19]([CH3:21])=O)=O)=[O:15]>C(O)C>[CH2:7]([N:9]1[C:19]([CH3:21])=[CH:18][C:16]([C:14]([O:13][CH2:12][CH3:11])=[O:15])=[N:10]1)[CH3:8]

Participants

4

Reactant 2

HCID 69208Ethyl 2,4-dioxovalerateHCID 96181Hydrazine, ethyl-, ethanedioate (1:1)

Product 1

HCID 16394811Ethyl 1-ethyl-5-methyl-1H-pyrazole-3-carboxylateYield 100.5%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Ethylhydrazine oxalate (23.7 g, 158 mmol) was added slowly to an 11° C. solution of ethyl acetopyruvate (50.0 g, 316 mmol) in ethanol so that the internal temperature did not exceed 14° C. The reaction was allowed to warm to ambient temperature and was stirred overnight. The reaction was concentrated under reduced pressure and 2 M sodium carbonate was added to adjust the mixture to pH 9. The mixture was transferred to a separatory funnel. The aqueous phase was extracted with methyl tert-butyl ether (3×600 mL). The organic layers were combined, dried over magnesium sulfate, filtered, and concentrated under reduced pressure to yield 28.94 g of ethyl 1-ethyl-5-methyl-1H-pyrazole-3-carboxylate as an orange oil that was used without purification in the next reaction.

Workup

  1. customdid not exceed 14° C
  2. concentrationThe reaction was concentrated under reduced pressure and 2 M sodium carbonate
  3. additionwas added
  4. customThe mixture was transferred to a separatory funnel
  5. extractionThe aqueous phase was extracted with methyl tert-butyl ether (3×600 mL)
  6. dry with materialdried over magnesium sulfate
  7. filtrationfiltered
  8. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-08d9deb8acff49c891f04e4b57649dd2
Source dataset
uspto-grants-2011_02
Patent number
US07879849B2

Reaction notes

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