Water → 1,5-Dimethyl-3-ethoxycarbonylpyrazole

HRID 1452081

Reaktionsgleichung

Reaktionsgleichung von HRID 1452081
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]

Komponenten

6

Edukt 4

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

Produkt 1

HCID 1385771,5-Dimethyl-3-ethoxycarbonylpyrazole

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 176Acetic AcidLösungsmittel

Versuchsvorschrift

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% ).

Aufarbeitung

  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

Quellen und Nachweise

ORD-Eintrag
ord-b71efcf5e9aa4651bd33ef6c61d6e0b4
Quelldatensatz
uspto-grants-1997_02
Patentnummer
US05606051

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