反应详情

Mixture of 2-benzoylamino-4-methyl-3-oxo-pentanoic acid benzyl ester (1.08 g, 3 mmol), triphenylphosphine (2.01 g, 8 mmol), and iodine (1.62 g, 6.37 mmol) in tetrahydrofuran (60 mL) was cooled to −78 degrees, followed by addition of triethylamine (1.7 mL). The resulted solution was stirred at −78 degrees for about 10 min, and then was warmed up to room temperature. The reaction continued at room temperature for about 1 hr. After the reaction, the solvent was removed, and dichloromethane was added. The resulted solution was washed in sequence with saturated sodium bicarbonate, citric acid (0.5 M), and brine, dried over sodium sulfate, filtered and then concentrated in vacuo. Flash chromatography (Merck silica gel 60, 230-400 mesh, 0-40% ethyl acetate in hexane for 20 min) gave 5-isopropyl-2-phenyl-oxazole-4-carboxylic acid benzyl ester (0.84 g, 82%) as a light yellow solid. LCMS calcd for C20H19NO3 (m/e) 321, obsd 322 (M+H).

1. temperaturewas cooled to −78 degrees
2. waitThe reaction continued at room temperature for about 1 hr
3. customAfter the reaction
4. customthe solvent was removed
5. additiondichloromethane was added
6. washThe resulted solution was washed in sequence with saturated sodium bicarbonate, citric acid (0.5 M), and brine
7. dry with materialdried over sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated in vacuo