反应详情

A mixture of Cbz-L-serine (10.0 g, 42 mmol), benzyltriethylammonium chloride (9.5 g, 42 mmol) and potassium carbonate (38.0 g, 275 mmol) in CH3CN (80 mL) was stirred vigorously for 5 h at RT. 2-Bromo-2-methyl propane was added and the reaction mixture was warmed to 45-50° C. and stirred rapidly. The reaction mixture became very thick after 2-3 h. Additional CH3CN was added (50 mL) to facilitate stirring and the resulting reaction mixture was stirred for 24 h. The reaction mixture was then cooled to RT and most of the CH3CN was removed by rotary evaporation. The reaction mixture was then partitioned between ethyl acetate (200 mL) and water (100 mL). The aqueous layer was extracted with ethyl acetate (3×100 mL). The ethyl acetate layers were combined and washed with water (100 mL), then with sat. aq. NaCl solution (2×100 mL), and then dried over Na2SO4, filtered and concentrated. If the product did not crystallize upon concentration, it was triturated with hexanes and filtered to give 2-benzyloxycarbonylamino-3-hydroxy-propionic acid tert-butyl ester as a white solid (10.0 g, 81% yield).

1. temperaturethe reaction mixture was warmed to 45-50° C.
2. stirringstirred rapidly
3. waitThe reaction mixture became very thick after 2-3 h
4. stirringto facilitate stirring
5. customthe resulting reaction mixture
6. stirringwas stirred for 24 h
7. customwas removed by rotary evaporation
8. customThe reaction mixture was then partitioned between ethyl acetate (200 mL) and water (100 mL)
9. extractionThe aqueous layer was extracted with ethyl acetate (3×100 mL)
10. washwashed with water (100 mL)
11. dry with materialwith sat. aq. NaCl solution (2×100 mL), and then dried over Na2SO4
12. filtrationfiltered
13. concentrationconcentrated
14. customIf the product did not crystallize upon concentration, it
15. customwas triturated with hexanes
16. filtrationfiltered