反应详情

To a mixture of diethyl malonate (115.8 g) and tetrahydrofuran (300 mL) was added sodium hydride (60%, oil, 24.12 g) under ice-cooling. After stirring the mixture at room temperature for 30 min., a solution (100 mL) of 4-chloromethyl-5-methyl-2-phenyloxazole (50.0 g) in tetrahydrofuran was added to the reaction mixture under ice-cooling, and the mixture was heated under reflux for 1 hr. Water was added to the reaction mixture, and the mixture was concentrated. Ethyl acetate was added to the residue and the mixture was washed with saturated brine, dried over anhydrous magnesium sulfate and concentrated to give an oil. A mixture of this oil, 6N hydrochloric acid (300 mL) and acetic acid (150 ml) was heated under reflux for 20 hrs. The reaction mixture was concentrated, and ethyl acetate was added to the residue. The mixture was washed with saturated brine, dried over anhydrous magnesium sulfate and concentrated. The residue was subjected to silica gel column chromatography to give crystals (22.4 g, 40%) of 3-(5-methyl-2-phenyl-4-oxazolyl)propionic acid from a fraction eluted with ethyl acetate-hexane (1:4, v/v). Recrystallization from ethyl acetate-hexane gave colorless prism crystals. melting point: 124-125° C.

1. temperaturecooling
2. temperaturecooling
3. temperaturethe mixture was heated
4. temperatureunder reflux for 1 hr
5. concentrationthe mixture was concentrated
6. additionEthyl acetate was added to the residue
7. washthe mixture was washed with saturated brine
8. dry with materialdried over anhydrous magnesium sulfate
9. concentrationconcentrated
10. customto give an oil
11. temperaturewas heated
12. temperatureunder reflux for 20 hrs
13. concentrationThe reaction mixture was concentrated
14. additionethyl acetate was added to the residue
15. washThe mixture was washed with saturated brine
16. dry with materialdried over anhydrous magnesium sulfate
17. concentrationconcentrated