Reaktion #71125

Reaktionsgleichung

3-bromo-2-oxo-propionic acid ethyl ester

trifluoroacetic anhydride

Na2CO3

N2

3-Bromo-2-oxo-propionic acid ethyl ester

3-phenyl-acrylamide

NaHCO3

→

title compound

(E)-2-Styryl-oxazole-4-carboxylic acid ethyl ester

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe reaction mixture was heated
2. 2
   Temperaturat reflux for 15 h
3. 3
   Temperaturat reflux for 15 h
4. 4
   FiltrationThe reaction mixture was then filtered over celite
5. 5
   Sonstigethe solvents were evaporated under reduced pressure
6. 6
   workup.DISSOLUTIONThe residue was dissolved in THF (30 mL)
7. 7
   workup.ADDITIONtreated at 0° C.
8. 8
   workup.STIRRINGThe reaction mixture was then stirred at rt overnight
9. 9
   Extraktionthe mixture was extracted with EA (3×150 mL)
10. 10
    Trocknendried over MgSO4
11. 11
    Filtrationfiltered
12. 12
    Sonstigethe solvent was removed under reduced pressure
13. 13
    SonstigePurification of the residue by FC (1:9 EA-Hept)

Vorschrift

In a flame dried round-bottomed flask equipped with a magnetic stir bar and under inert atmosphere (N2), a suspension of 3-phenyl-acrylamide (10.31 g, 67.95 mmol) and NaHCO3 (28.47 g, 339.73 mmol) in THF (260 mL) was treated with 3-bromo-2-oxo-propionic acid ethyl ester (13.04 mL, 88.33 mmol) and the reaction mixture was heated at reflux for 15 h. 3-Bromo-2-oxo-propionic acid ethyl ester (13.04 mL, 88.33 mmol) was added again and the reaction mixture was stirred at reflux for 15 h. The reaction mixture was then filtered over celite and the solvents were evaporated under reduced pressure. The residue was dissolved in THF (30 mL) and treated at 0° C., dropwise, with trifluoroacetic anhydride (30.0 mL, 215.83 mmol). The reaction mixture was then stirred at rt overnight. Sat. aq. Na2CO3 was added and the mixture was extracted with EA (3×150 mL), dried over MgSO4, filtered, and the solvent was removed under reduced pressure. Purification of the residue by FC (1:9 EA-Hept) gave the title compound as a yellow solid. TLC:rf (1:9 EA-Hept)=0.1. LC-MS-conditions 02: tR=1.01 min; [M+H]+=244.48.

Quelle