反应详情

To a stirring solution of (S)-4-(benzyloxycarbonylamino)-2-hydroxybutanoic acid (1, 612 g, 2.41 mol) in THF (6 L) at 0° C. was added DMAP (2.4 g) and pyridine (196 mL, 2.41 mol). After stirring for 20 minutes, benzoyl chloride (280 mL) was added slowly and the reaction was allowed to stir overnight at room temperature. The resulting precipitate was filtered and the filtrate was acidified with 1 M citric acid (1 L). The organic solvent was removed by rotary evaporation and the desired product was extracted with EtOAc (2×2 L). The combined organic layers were washed with 1 M citric acid (1 L), brine (1 L) and then dried over MgSO4. Solvent removal under vacuum resulted in a viscous oil, which was purified on a 6-inch reverse-phase HPLC column to yield (S)-2-(benzoyloxy)-4-(benzyloxycarbonylamino)butanoic acid (2) as a non-flowing viscous oil (439 g, 51% yield).

1. stirringto stir overnight at room temperature
2. filtrationThe resulting precipitate was filtered
3. customThe organic solvent was removed by rotary evaporation
4. extractionthe desired product was extracted with EtOAc (2×2 L)
5. washThe combined organic layers were washed with 1 M citric acid (1 L), brine (1 L)
6. dry with materialdried over MgSO4
7. customSolvent removal under vacuum
8. customresulted in a viscous oil, which
9. customwas purified on a 6-inch reverse-phase HPLC column