反应详情

Thionyl chloride (5.25 mL, 72 mmol, 3.6 equiv.) is added dropwise to a 0° C. solution of absolute ethyl alcohol (20 ml). Diisopropyl ethylamine (3.45 ml, 19. mmol, 1 equiv.) was added and then 4.8 g of N-CBZ-L-serine methyl ester was added as a solid. Stirring is continued for 16 hours at room temperature. The ethanol and thionyl chloride are then removed by rotary evaporation and the residue is dissolved in ethyl acetate (200 ml). The organic phase is washed with 1N hydrochloric acid (50 ml) and saturated sodium bicarbonate (50 ml) and brine (20 ml). The organic layer is dried with magnesium sulfate. Rotary evaporation of the product gives an oil which is chromatographed on silica gel with hexane/ethyl acetate (3:1) to give N-CBZ-L-serine ethyl ester.

1. customThe ethanol and thionyl chloride are then removed by rotary evaporation
2. dissolutionthe residue is dissolved in ethyl acetate (200 ml)
3. washThe organic phase is washed with 1N hydrochloric acid (50 ml) and saturated sodium bicarbonate (50 ml) and brine (20 ml)
4. dry with materialThe organic layer is dried with magnesium sulfate
5. customRotary evaporation of the product
6. customgives an oil which
7. customis chromatographed on silica gel with hexane/ethyl acetate (3:1)