Ethyl-2,4-dioxohexanoate → Ethyl 1,5-diethylpyrazole-3-carboxylate

HRID 1360417Notes

Reaction equation

HRID 1360417 reaction equation
O=[C:2]([CH2:8][C:9](=O)[CH2:10][CH3:11])[C:3]([O:5][CH2:6][CH3:7])=[O:4].C(O)(=O)C(O)=O.[CH2:19]([NH:21][NH2:22])[CH3:20]>C(O)(=O)C>[CH2:19]([N:21]1[C:9]([CH2:10][CH3:11])=[CH:8][C:2]([C:3]([O:5][CH2:6][CH3:7])=[O:4])=[N:22]1)[CH3:20]

Participants

4

Reactant 2

HCID 61590Ethyl-2,4-dioxohexanoateHCID 96181Hydrazine, ethyl-, ethanedioate (1:1)

Product 1

HCID 22145420Ethyl 1,5-diethylpyrazole-3-carboxylateYield 54.3%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A solution of ethyl 2,4-dioxohexanoate (˜0.345 mol), prepared as described in Part A of Example 10, in glacial acetic acid (350 mL) was cooled to 0° C. Ethylhydrazine oxalate (41.43 g, 0.276 mol) was added over a period of 20 minutes. The reaction was allowed to warm to ambient temperature, stirred for 20 hours, and concentrated under reduced pressure. The residue was adjusted to pH 10 with the addition of 2 M aqueous sodium carbonate, and chloroform was added. The mixture was filtered to remove a solid. The aqueous filtrate was extracted with chloroform (3×), and the combined organic fractions were dried over sodium sulfate, filtered, and concentrated under reduced pressure to provide 29.4 g of ethyl 1,5-diethyl-1H-pyrazole-3-carboxylate as an orange oil, which was used without purification.

Workup

  1. concentrationconcentrated under reduced pressure
  2. additionThe residue was adjusted to pH 10 with the addition of 2 M aqueous sodium carbonate, and chloroform
  3. additionwas added
  4. filtrationThe mixture was filtered
  5. customto remove a solid
  6. extractionThe aqueous filtrate was extracted with chloroform (3×)
  7. dry with materialthe combined organic fractions were dried over sodium sulfate
  8. filtrationfiltered
  9. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-fdd654582b684e6bb5865e348fda7e8d
Source dataset
uspto-grants-2011_02
Patent number
US07879849B2

Reaction notes

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