反应详情

In this example, 3.0 g of 1-(3,4-methylenedioxybenzoylmethyl)-4-(2-oxo-3,4-dihydro-2H-1,3-benzoxazin-3-yl)-piperidine obtained in Example 2 is mixed with 150 ml of methanol. While the mixture is stirred at 0° to 10° C., 0.8 g of sodium borohydride is added thereto over a period of 3 hours. Then, the mixture is stirred overnight at room temperature. The mixture is further mixed with 0.4 g of sodium borohydride and stirred at room temperature for 3 hours. The white crystals deposited are separated by filtration, washed with methanol and water and dried to obtain 2.36 g of a crude product. In the meantime, the filtrate is concentrated under reduced pressure. The residue is mixed with water. The crystals deposited are separated by filtration, washed with water and dried to obtain 0.37 g of a crude product. The two crude products are combined and recrystallized from ethanol to obtain 2.49 g of the desired product.

1. stirringThen, the mixture is stirred overnight at room temperature
2. stirringstirred at room temperature for 3 hours
3. customThe white crystals deposited are separated by filtration
4. washwashed with methanol and water
5. customdried
6. customto obtain 2.36 g of a crude product
7. concentrationIn the meantime, the filtrate is concentrated under reduced pressure
8. additionThe residue is mixed with water
9. customThe crystals deposited are separated by filtration
10. washwashed with water
11. customdried
12. customto obtain 0.37 g of a crude product
13. customrecrystallized from ethanol