Water → 1,5-Dimethyl-3-ethoxycarbonylpyrazole

HRID 1825331

Reaction equation

HRID 1825331 reaction equation
O=[C:2]([CH2:8][C:9](=O)[CH3:10])[C:3]([O:5][CH2:6][CH3:7])=[O:4].[CH3:12][NH:13][NH2:14].C(OCC)(=O)C.O>C(O)(=O)C>[CH2:6]([O:5][C:3]([C:2]1[CH:8]=[C:9]([CH3:10])[N:13]([CH3:12])[N:14]=1)=[O:4])[CH3:7]

Participants

6

Reactant 4

HCID 962WaterHCID 6061MethylhydrazineHCID 8857Ethyl AcetateHCID 69208Ethyl 2,4-dioxovalerate

Product 1

HCID 1385771,5-Dimethyl-3-ethoxycarbonylpyrazole

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

Ethyl 2,4-dioxovalerate (5.6 ml, 40 mM) was dissolved in glacial acetic acid (35 ml) before cooling the-reaction temperature to 8-10° C. Methylhydrazine (2.0 ml, 38 mM) was added dropwise so that the reaction temperature did not rise above 15° C. After stirring at room temperature for 90 minutes the reaction was poured into ethyl acetate and water. The organic phase was washed with saturated sodium bicarbonate solution, water and brine before drying (MgSO4). Purification was accomplished was by chromatography on silica gel (10×4.5 cm) loading in dichloromethane and eluting with 50% ethyl acetate in hexane. Evaporation of solvent gave the title compound as a coloured oil which crystallised on standing (4.69 g); υmax (CH2Cl2) 1717 and 1223 cm−1; δH (CDCl3) 1.39 (3H, t, J 7.13 Hz), 2.30 (3H, s), 3.85 (3H, s), 4.39 (2H, q, J 7.21 Hz), 6.57 (1H, s); E.I. m/e 168 (25%).

Workup

  1. temperaturebefore cooling
  2. customthe-reaction temperature to 8-10° C
  3. customdid not rise above 15° C
  4. washThe organic phase was washed with saturated sodium bicarbonate solution, water and brine
  5. dry with materialbefore drying (MgSO4)
  6. customPurification
  7. washeluting with 50% ethyl acetate in hexane
  8. customEvaporation of solvent

Sources & evidence

ORD record
ord-58464fc4319b4dd78e46328d58954e3f
Source dataset
uspto-grants-2006_05
Patent number
US07045619B2

Linked notes

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