Water → 1,5-Dimethyl-3-ethoxycarbonylpyrazole

HRID 976983

Reaction equation

HRID 976983 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); νmax (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 the reaction temperature to 8°-10° C
  2. customdid not rise above 15° C
  3. washThe organic phase was washed with saturated sodium bicarbonate solution, water and brine
  4. dry with materialbefore drying (MgSO4)
  5. customPurification
  6. washeluting with 50% ethyl acetate in hexane
  7. customEvaporation of solvent

Sources & evidence

ORD record
ord-d48a9f0db23f4cca9faa341a82c62c3d
Source dataset
uspto-grants-1997_03
Patent number
US05612477

Linked notes

Loading…