Hydrazine → 1H-Pyrazole-3-carboxylic acid, 5-ethyl-, ethyl ester

HRID 1360454Notes

Reaction equation

HRID 1360454 reaction equation
O=[C:2]([CH2:8][C:9](=O)[CH2:10][CH3:11])[C:3]([O:5][CH2:6][CH3:7])=[O:4].[NH2:13][NH2:14]>C(O)(=O)C>[CH2:10]([C:9]1[NH:14][N:13]=[C:2]([C:3]([O:5][CH2:6][CH3:7])=[O:4])[CH:8]=1)[CH3:11]

Participants

4

Reactant 2

HCID 9321HydrazineHCID 61590Ethyl-2,4-dioxohexanoate

Product 1

HCID 80276141H-Pyrazole-3-carboxylic acid, 5-ethyl-, ethyl esterYield 57.7%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A solution of ethyl 2,4-dioxohexanoate (˜0.464 mol), prepared as described in Part A of Example 10, in glacial acetic acid (300 mL) was cooled to 0° C. Hydrazine (8.91 g, 0.278 mol) was added dropwise. The reaction was allowed to warm to ambient temperature, stirred overnight, and concentrated under reduced pressure. The residue was adjusted to pH 10 with the addition of 2 M aqueous sodium carbonate. The mixture was extracted with chloroform (3×250 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated under reduced pressure to provide 27.0 g of ethyl 5-ethyl-1H-pyrazole-3-carboxylate, 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
  3. extractionThe mixture was extracted with chloroform (3×250 mL)
  4. dry with materialThe combined organic layers were dried over sodium sulfate
  5. filtrationfiltered
  6. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-8ffcbb7d030a4a07b665e8afb724010d
Source dataset
uspto-grants-2011_02
Patent number
US07879849B2

Reaction notes

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