2-Propenamide, 3-phenyl- → ethyl 2-[(E)-2-phenylethenyl]-1,3-oxazole-4-carboxylate

HRID 1397386Notes

Reaction equation

HRID 1397386 reaction equation
Br[CH2:2][C:3](=O)[C:4]([O:6][CH2:7][CH3:8])=[O:5].[C:10]1([CH:16]=[CH:17][C:18]([NH2:20])=[O:19])[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1.C([O-])(O)=O.[Na+]>C1COCC1>[CH:17](/[C:18]1[O:19][CH:2]=[C:3]([C:4]([O:6][CH2:7][CH3:8])=[O:5])[N:20]=1)=[CH:16]\[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1

Participants

5

Reactant 3

HCID 121352-Propenamide, 3-phenyl-HCID 66144Ethyl bromopyruvateHCID 516892Sodium Bicarbonate

Product 1

HCID 5708074ethyl 2-[(E)-2-phenylethenyl]-1,3-oxazole-4-carboxylateYield 51.1%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

Ethyl bromopyruvate (10 mL, 81.55 mmol) was added dropwise to a solution of 3-phenylacrylamide (5 g, 33.97 mmol) and NaHCO3 (11.42 g, 135.89 mmol) in anhydrous THF (120 mL) at 0° C. The reaction mixture was heated to reflux for 23 h. The mixture was then filtered through Celite and the solvent was removed under reduced pressure. The crude product was dissolved in anhydrous THF (80 mL) and trifluoroacetic anhydride (37 mL) was added dropwise at 0° C. The reaction mixture was stirred at room temperature for 10 h, and quenched with saturated NaHCO3 solution at 0° C. The organic product was extracted with EtOAc, and the combined extracts were washed with brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product was purified by column chromatography (silica gel 60-120 mesh, eluent 10% EtOAc in petroleum ether) to afford (E)-ethyl 2-styryloxazole-4-carboxylate (4.22 g, yield 51%) as an off white solid. 1H NMR (300 MHz, CDCl3) δ 8.21 (s, 1H), 7.66-7.61 (d, J=16.4 Hz, 1H), 7.56-7.52 (m, 2H), 7.44-7.36 (m, 3H), 7.00-6.94 (d, J=16.4 Hz, 1H), 4.46-4.39 (q, J=7.0 Hz, 2H), 1.44-1.39 (t, J=7.0 Hz, 3H). MS (ESI) m/z: Calculated for C14H13NO3: 243.09. found: 243.8 (M+H)+.

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureto reflux for 23 h
  3. filtrationThe mixture was then filtered through Celite
  4. customthe solvent was removed under reduced pressure
  5. dissolutionThe crude product was dissolved in anhydrous THF (80 mL)
  6. additiontrifluoroacetic anhydride (37 mL) was added dropwise at 0° C
  7. customquenched with saturated NaHCO3 solution at 0° C
  8. extractionThe organic product was extracted with EtOAc
  9. washthe combined extracts were washed with brine
  10. dry with materialdried over anhydrous sodium sulfate
  11. concentrationconcentrated under reduced pressure
  12. customThe crude product was purified by column chromatography (silica gel 60-120 mesh, eluent 10% EtOAc in petroleum ether)

Sources & evidence

ORD record
ord-ca51afa57b5e42d5826257c93afe8139
Source dataset
uspto-grants-2014_12
Patent number
US08901156B2

Reaction notes

Loading…