反应详情

温度

60 °C

Methyl 2-(5-methyl-2-phenyl-4-oxazolyl)acetate (compound [5]; 170 g) obtained in Example 2 was dissolved in tetrahydrofuran (935 mL) and sodium borohydride (27.81 g) was added at room temperature. This suspension was heated to 60° C. and stirred, and methyl alcohol (57.9 mL) was added dropwise over 1 hr. After dropwise addition, the reaction mixture was cooled to room temperature and water (35 mL) was added dropwise. The mixture was stirred at room temperature for 1 hr and filtered to remove solid components. The solid components were washed with tetrahydrofuran and the washing was combined with the previous filtrate, which was followed by concentration under reduced pressure. Ethyl acetate (1 L) was added to the residue and after dissolution, water (1 L) was added for partitioning. The aqueous layer was again extracted with ethyl acetate (0.5 L), and the organic layers were combined and washed successively with saturated sodium hydrogencarbonate solution (1 L) and saturated brine (1 L) and dried over anhydrous magnesium sulfate. After filtration, the filtrate was concentrated under reduced pressure to give crude crystals (compound [6]; 149 g). The crystals were recrystallized from a mixed solvent of n-hexane (1 L) and ethyl acetate (0.2 L) to give the title compound (compound [6]; 134 g, yield 89.7%).

1. additionAfter dropwise addition
2. temperaturethe reaction mixture was cooled to room temperature
3. stirringThe mixture was stirred at room temperature for 1 hr
4. filtrationfiltered
5. customto remove solid components
6. washThe solid components were washed with tetrahydrofuran
7. concentrationwas followed by concentration under reduced pressure
8. additionEthyl acetate (1 L) was added to the residue
9. dissolutionafter dissolution, water (1 L)
10. additionwas added
11. customfor partitioning
12. extractionThe aqueous layer was again extracted with ethyl acetate (0.5 L)
13. washwashed successively with saturated sodium hydrogencarbonate solution (1 L) and saturated brine (1 L)
14. dry with materialdried over anhydrous magnesium sulfate
15. filtrationAfter filtration
16. concentrationthe filtrate was concentrated under reduced pressure