2-Oxime 2,3-butanedione → Ethyl 5-(4-chloromethyl-5-methyl-1,3-oxazol-2-yl)thiophene-2-carboxylate

HRID 2221642

Reaktionsgleichung

Reaktionsgleichung von HRID 2221642
[CH:1]([C:3]1[S:7][C:6]([C:8]([O:10][CH2:11][CH3:12])=[O:9])=[CH:5][CH:4]=1)=[O:2].[CH3:13][C:14](=[N:18]O)[C:15](=O)[CH3:16].[ClH:20].C(OCC)(=O)C>>[Cl:20][CH2:13][C:14]1[N:18]=[C:1]([C:3]2[S:7][C:6]([C:8]([O:10][CH2:11][CH3:12])=[O:9])=[CH:5][CH:4]=2)[O:2][C:15]=1[CH3:16]

Komponenten

4

Edukt 3

HCID 63989692-Oxime 2,3-butanedioneHCID 10797570Ethyl 5-formylthiophene-2-carboxylateHCID 21866389Hydrogen chloride-ethyl acetate

Produkt 1

HCID 23076614Ethyl 5-(4-chloromethyl-5-methyl-1,3-oxazol-2-yl)thiophene-2-carboxylateAusbeute 24 %

Versuchsvorschrift

A mixture of ethyl 5-formylthiophene-2-carboxylate (14.6 g), 2,3-butanedione-2-oxime (8.02 g) and 4N hydrogenchloride-ethyl acetate (300 mL) was stirred at room temperature for 15 hrs. The reaction mixture was concentrated, diethyl ether was added to the residue to allow precipitation of crystals, and crystals were collected by filtration. A mixture of the obtained crystal, tetrahydrofuran (500 mL) and thionyl chloride (14.16 g) was heated under reflux for 2 hrs. The reaction mixture was concentrated and ethyl acetate was added to the residue. The ethyl acetate layer was washed successively with saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous magnesium sulfate and concentrated. The obtained residue was subjected to silica gel column chromatography and eluted with ethyl acetate-hexane (1:6, v/v) to give ethyl 5-(4-chloromethyl-5-methyl-1,3-oxazol-2-yl)thiophene-2-carboxylate as colorless crystals (5.41 g, yield 24%). Recrystallization from ethyl acetate-hexane gave colorless prism crystals. melting point: 101-102° C.

Aufarbeitung

  1. concentrationThe reaction mixture was concentrated
  2. additiondiethyl ether was added to the residue
  3. customprecipitation of crystals, and crystals
  4. filtrationwere collected by filtration
  5. additionA mixture of the obtained crystal, tetrahydrofuran (500 mL) and thionyl chloride (14.16 g)
  6. temperaturewas heated
  7. temperatureunder reflux for 2 hrs
  8. concentrationThe reaction mixture was concentrated
  9. additionethyl acetate was added to the residue
  10. washThe ethyl acetate layer was washed successively with saturated aqueous sodium hydrogen carbonate solution and saturated brine
  11. dry with materialdried over anhydrous magnesium sulfate
  12. concentrationconcentrated
  13. washeluted with ethyl acetate-hexane (1:6, v/v)

Quellen und Nachweise

ORD-Eintrag
ord-153c4d47d5ca4274ba664f148409f6ca
Quelldatensatz
uspto-grants-2008_05
Patentnummer
US07368578B2

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