Triethylamine → (S,E)-3-(pent-2-enoyl)-4-phenyloxazolidin-2-one

Temperature

0 °C

To a solution of 2-pentenoic acid (5.44 g, 54 mmol) and triethylamine (6 g, 60 mmol) in anhydrous tetrahydrofuran (120 mL) under nitrogen at −78° C. was added trimethylacetyl chloride (7.36 mL, 60 mmol). The reaction mixture was stirred at −78° C. for 10 minutes, 0° C. for 1 hour, then re-cooled to −78° C. At the same time, in a seperate flask charged with a solution of (S)-(+)-4-phenyl-2-oxazolidinone (8.86 g, 54 mmol) in anhydrous tetrahydrofuran (130 mL) under nitrogen at −78° C. was added dropwise a solution of n-butyl lithium (22 mL, 54 mmol, 2.5 M in hexanes). The mixture was stirred at −78° C. for 20 minutes and then transferred via a cannula into the reaction flask containing the mixed anhydride at −78° C. The reaction mixture was stirred at 0° C. for 1 hour, then warmed to room temperature and stirred for 18 hours. The mixture was quenched with saturated aqueous ammonium chloride solution (200 mL), concentrated to about half of its original volume under reduced pressure to remove tetrahydrofuran. The remaining mixture was extracted with ethyl acetate (2×250 mL). The organic layer was separated, combined, dried over sodium sulfate and concentrated under reduced pressure. The residue was purified by chromatography over silica gel eluted with 2:1 ethyl acetate/hexanes to give (S)-3-((E)-pent-2-enoyl)-4-phenyl-oxazolidin-2-one as a white foam (9.9 g, 75%).

1. temperaturere-cooled to −78° C
2. stirringThe mixture was stirred at −78° C. for 20 minutes
3. stirringThe reaction mixture was stirred at 0° C. for 1 hour
4. temperaturewarmed to room temperature
5. stirringstirred for 18 hours
6. customThe mixture was quenched with saturated aqueous ammonium chloride solution (200 mL)
7. concentrationconcentrated to about half of its original volume under reduced pressure
8. customto remove tetrahydrofuran
9. extractionThe remaining mixture was extracted with ethyl acetate (2×250 mL)
10. customThe organic layer was separated
11. dry with materialdried over sodium sulfate
12. concentrationconcentrated under reduced pressure
13. customThe residue was purified by chromatography over silica gel
14. washeluted with 2:1 ethyl acetate/hexanes

ORD record

ord-53421b5e9a7b4975b298fee024fee84d

Source dataset

uspto-grants-2008_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07427635B2