Pyridine → (S)-2-(benzoyloxy)-4-(benzyloxycarbonylamino)butanoic acid

Beteiligte Stoffe

Reaktionsschritte

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).

Herkunft & Nachweise