2,4-Dioxo-4-phenyl-butyric acid ethyl ester → Methyl 5-phenyl-1,2-oxazole-3-carboxylate

HRID 1093580

Reaktionsgleichung

Reaktionsgleichung von HRID 1093580
[CH2:1]([O:3][C:4](=[O:16])[C:5](=O)[CH2:6][C:7](=[O:14])[C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1)C.Cl.[NH2:18]O>CO>[CH3:1][O:3][C:4]([C:5]1[CH:6]=[C:7]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=2)[O:14][N:18]=1)=[O:16]

Komponenten

4

Edukt 2

HCID 2265032,4-Dioxo-4-phenyl-butyric acid ethyl esterHCID 443297Hydroxyamine hydrochloride

Produkt 1

HCID 905953Methyl 5-phenyl-1,2-oxazole-3-carboxylateAusbeute 79 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 887MethanolLösungsmittel

Versuchsvorschrift

To a stirred solution of 2,4-dioxo-4-phenyl-butyric acid ethyl ester (3.86 g, 0.01754 mole) in methanol (78 mL) was added hydroxylamine hydrochloride (3.657 g, 0.0526 mole) at ambient temperature. The resulting mixture was then heated to reflux overnight. Volatiles were then removed by evaporation and the resulting residue was diluted with water and the product extracted with chloroform. The chloroform layer was collected and washed with brine solution, dried over sodium sulfate and concentrated under reduced pressure. The resulting residue was purified by column chromatography using silica gel 60-120 mesh (4% ethyl acetate in hexane) to afford 2.8 g (79%) of 5-phenyl-isoxazole-3-carboxylic acid methyl ester. LCMS: 204.06 (M+1)+, 97.58%. To a stirred solution of 5-phenyl-isoxazole-3-carboxylic acid methyl ester (2.8 g, 0.01379 mol) in a mixture of THF (10 mL), methanol (10 mL) and H2O (10 mL) was added LiOH.H2O (0.87 g, 0.02073 mol) and the resulting mixture was stirred at ambient temperature for 2.5 hours. Volatiles were then evaporated and the resulting residue was diluted with water, acidified with concentrated HCl and extracted with ethyl acetate. The ethyl acetate layer was collected and washed with brine solution, dried over sodium sulfate and concentrated under reduced pressure to afford 2.2 g (85%) of 5-phenyl-isoxazole-3-carboxylic acid. LCMS: 190.04 (M+1)+, 96.4%.

Aufarbeitung

  1. temperatureThe resulting mixture was then heated
  2. temperatureto reflux overnight
  3. customVolatiles were then removed by evaporation
  4. additionthe resulting residue was diluted with water
  5. extractionthe product extracted with chloroform
  6. customThe chloroform layer was collected
  7. washwashed with brine solution
  8. dry with materialdried over sodium sulfate
  9. concentrationconcentrated under reduced pressure
  10. customThe resulting residue was purified by column chromatography

Quellen und Nachweise

ORD-Eintrag
ord-313a25e6dfde479ba74ad7d924cefc17
Quelldatensatz
uspto-grants-2012_03
Patentnummer
US08129376B2

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