反应详情

温度

0 °C

To a solution of 1,1-dimethylethyl 4-piperidinylcarbamate (50 g) was added tetrahydro-4H-pyran-4-one (35.75 g) in dry DCM (1000 ml), then was added sodium triacetoxyborohydride (141 g) portion wise over 10 minutes at about 25° C. The mixture was stirred under nitrogen for about 30 hours, then cooled to 0° C. Water (107 ml) was added portion wise in 20 minutes, followed by saturated aqueous potassium carbonate (178 ml) and saturated brine (178 g in 178 ml). The mixture was stirred for 10 minutes at about 25° C., then the layers were separated and the organic layer washed with saturated brine (3×214 ml). After drying over anhydrous sodium sulphate, the organic layer was concentrated and the residue was treated with 100 ml isopropanol and reconcentrated. The residue was slowly heated to reflux with 11% HCl in isopropanol (200 ml) for 2 hours then cooled to about 25° C. The solid was filtered, and slurry washed with diethyl ether (100 ml), then dried under high vacuum to give the title product (43 g).

1. stirringThe mixture was stirred for 10 minutes at about 25° C.
2. customthe layers were separated
3. washthe organic layer washed with saturated brine (3×214 ml)
4. dry with materialAfter drying over anhydrous sodium sulphate
5. concentrationthe organic layer was concentrated
6. additionthe residue was treated with 100 ml isopropanol
7. temperatureThe residue was slowly heated
8. temperatureto reflux with 11% HCl in isopropanol (200 ml) for 2 hours
9. temperaturethen cooled to about 25° C
10. filtrationThe solid was filtered
11. washslurry washed with diethyl ether (100 ml)
12. customdried under high vacuum