反应详情

To a solution of N-(t-butoxycarbonyl)-3-(3-pyridyl)alanine (5.0 g, 18.8 mmol) in methanol (100 mL), was added thionyl chloride (2M solution in dichloromethane, 66 mL, 132 mmol). The resulting solution was stirred overnight at ambient temperature. The methanol was removed under reduced pressure to a minimum volume and ethyl acetate (100 mL) was added. The resulting white precipitate was collected in a fritted funnel. To a solution of the collected precipitate in a mixture of tetrahydrofuran/water (40 mL each), was added di-tert-butyl dicarbonate (4.8 g, 21.99 mmol) and sodium carbonate (1.95 g, 18.4 mmol). After stirring for 12 hours at ambient temperature, the reaction mixture was diluted with ethyl acetate (40 mL) and washed with a solution of saturated sodium bicarbonate (25 mL). The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum to give crude product. This product was subjected to flash column chromatography on silica gel (230-400 mesh) using a 8×52 cm column and eluting with a 10:90 mixture of ethyl acetate/hexane, followed by a 60:40 mixture of ethyl acetate/hexane. 4 g (74%) of the title compound was obtained as an oil. Thin-layer chromatography (silica gel; ethyl acetate), Rf=0.68.

1. customThe methanol was removed under reduced pressure to a minimum volume and ethyl acetate (100 mL)
2. additionwas added
3. customThe resulting white precipitate was collected in a fritted funnel
4. additionTo a solution of the collected precipitate in a mixture of tetrahydrofuran/water (40 mL each)
5. stirringAfter stirring for 12 hours at ambient temperature
6. washwashed with a solution of saturated sodium bicarbonate (25 mL)
7. dry with materialThe organic layer was dried over anhydrous sodium sulfate
8. concentrationconcentrated under vacuum
9. customto give crude product
10. washeluting with a 10:90 mixture of ethyl acetate/hexane
11. additionfollowed by a 60:40 mixture of ethyl acetate/hexane