反应详情

温度

-78 °C

A mixture of 2-benzoylamino-4-methyl-3-oxo-butanoic acid benzyl ester (1.26 g, 3.88 mmol), triphenylphosphine (2.64 g, 10.09 mmol), and iodine (1.04 g, 8.225 mmol) in tetrahydrofuran (60 mL) was cooled to −78° C., followed by addition of triethylamine (2.18 mL, 15.52 mmol). The resulting solution was stirred at −78° C. for about 10 min, and then was warmed up to room temperature for about 1 hr. The solvent was removed and the residue was triturated with dichloromethane and filtered. The filtrate was evaporated and the residue dissolved in 70 mL of ethyl acetate, washed with 0.5 M citric acid (2×50 mL), saturated sodium bicarbonate (2×50 mL), and brine, dried over magnesium sulfate, filtered and then concentrated in vacuo. Flash chromatography (Merck silica gel 60, 230-400 mesh, 0-10% ethyl acetate in hexane) gave 5-ethyl-2-phenyl-oxazole-4-carboxylic acid benzyl ester (1 g) as a light yellow solid. LCMS calcd for C19H17NO3 (m/e) 321, obsd 322 (M+H).

1. temperaturewas warmed up to room temperature for about 1 hr
2. customThe solvent was removed
3. customthe residue was triturated with dichloromethane
4. filtrationfiltered
5. customThe filtrate was evaporated
6. dissolutionthe residue dissolved in 70 mL of ethyl acetate
7. washwashed with 0.5 M citric acid (2×50 mL), saturated sodium bicarbonate (2×50 mL), and brine
8. dry with materialdried over magnesium sulfate
9. filtrationfiltered
10. concentrationconcentrated in vacuo