Ethyl propiolate → Ethyl 3-bromo-1,2-oxazole-5-carboxylate

HRID 2233885Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 2233885
[Br:1][C:2](Br)=[N:3][OH:4].[C:6]([O:10][CH2:11][CH3:12])(=[O:9])[C:7]#[CH:8].C(=O)(O)[O-].[K+]>CCO.O>[Br:1][C:2]1[CH:8]=[C:7]([C:6]([O:10][CH2:11][CH3:12])=[O:9])[O:4][N:3]=1

Komponenten

6

Edukt 3

HCID 12182Ethyl propiolateHCID 516893Potassium BicarbonateHCID 27632191-bromo-N-hydroxymethanecarbonimidoyl bromide

Produkt 1

HCID 13802099Ethyl 3-bromo-1,2-oxazole-5-carboxylateAusbeute 78 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 702EthanolLösungsmittelHCID 962WaterLösungsmittel2×

Versuchsvorschrift

Dibromoformaldoxime (407 mg, 2.07 mmol) (prepared via the procedure of J C Rohloff, et. al., Tetrahedron Lett 1992, 33:3113-6), and ethyl propiolate (311 mg, 3.17 mmol) were dissolved in 10 ml of 50% aqueous EtOH. While stirring, a solution of 243 mg (2.43 mmol) of potassium bicarbonate in 5 ml of water was added dropwise over 1 h. The resulting solution was stirred for an additional 4 h, diluted with 25 ml of water, and extracted with chloroform (3×25 ml). The combined organic extract was dried over sodium sulfate and concentrated in vacuo to a colourless oil, 345 mg (78% yield) as a 7:1 mixture of the 5- and 4-carboxylates.

Aufarbeitung

  1. stirringThe resulting solution was stirred for an additional 4 h
  2. extractionextracted with chloroform (3×25 ml)
  3. extractionThe combined organic extract
  4. dry with materialwas dried over sodium sulfate
  5. concentrationconcentrated in vacuo to a colourless oil, 345 mg (78% yield) as a 7:1 mixture of the 5- and 4-carboxylates

Quellen und Nachweise

ORD-Eintrag
ord-fd2320ff1502494f87cb73eefdab2088
Quelldatensatz
uspto-grants-2010_05
Patentnummer
US07709503B2

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