Methylhydrazine → Ethyl 5-ethyl-1-methyl-1H-pyrazole-3-carboxylate

HRID 977006Notes

Reaction equation

HRID 977006 reaction equation
O=[C:2]([CH2:8][C:9](=O)[CH2:10][CH3:11])[C:3]([O:5][CH2:6][CH3:7])=[O:4].[CH3:13][NH:14][NH2:15]>C(O)(=O)C>[CH2:10]([C:9]1[N:14]([CH3:13])[N:15]=[C:2]([C:3]([O:5][CH2:6][CH3:7])=[O:4])[CH:8]=1)[CH3:11]

Participants

4

Reactant 2

HCID 6061MethylhydrazineHCID 61590Ethyl-2,4-dioxohexanoate

Product 1

HCID 22145397Ethyl 5-ethyl-1-methyl-1H-pyrazole-3-carboxylate

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

Ethyl 2,4-dioxohexanoate (12 g) in glacial acetic acid (75 ml) was cooled in an ice-bath and treated with methylhydrazine (3.21 g) in a dropwise fashion over 5-10 m. On complete addition the ice cooling was removed and the yellow homogeneous solution stirred at room temperature for ca. 2 h. The acetic acid was then removed in vacuo and the residual oil re-dissolved in ethyl acetate (~ 100 mls). The ethyl acetate solution was washed with saturated sodium hydrogen carbonate (3×) and brine. After drying over anhydrous magnesium sulphate the solvent was evaporated. The crude material was purified by silica gel chromatography eluting with 20-70% ethyl acetate/hexane giving the title compound as a pale yellow oil, (6.656 g, 52%); dH (CDCl3) 1.28 (3H, t, J7.6 Hz), 1.38 (3H, t, J7.1 Hz), 2.61 (2H, q, J7.6 Hz), 3.84 (3H, s), 4.38 (2H, q, J7.1 Hz) and 6.58 (1H, s).

Workup

  1. customwas removed
  2. customThe acetic acid was then removed in vacuo
  3. dissolutionthe residual oil re-dissolved in ethyl acetate (~ 100 mls)
  4. washThe ethyl acetate solution was washed with saturated sodium hydrogen carbonate (3×) and brine
  5. dry with materialAfter drying over anhydrous magnesium sulphate the solvent
  6. customwas evaporated
  7. customThe crude material was purified by silica gel chromatography
  8. washeluting with 20-70% ethyl acetate/hexane giving the title compound as a pale yellow oil, (6.656 g, 52%)

Sources & evidence

ORD record
ord-184c2c38406b4848ac412c165e6b07a8
Source dataset
uspto-grants-1997_03
Patent number
US05612477

Reaction notes

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