Citric Acid → Carbamic acid, N-(1-benzyl-2-hydroxyethyl)-, benzyl ester

Participants

Reaction Steps

To a solution of the objective compound of step (8) (109 g, 0.345 mol) in THF (500 mL) were added mortar-pulverized lithium chloride (29.2 g, 0.689 mol) and sodium tetrahydroborate (26.1 g, 0.690 mol). To the resulting suspension was added ethanol (1000 mL) with dropwise over 40 minutes, and the mixture was stirred at room temperature for 14 hours. To the reaction mixture was added 10% citric acid aqueous solution (700 mL), and the mixture was stirred at room temperature for 30 minutes. The organic solvent was distilled off under reduced pressure. The residue was added to water (700 mL) and extracted with dichloromethane. The extract was washed with saturated brine and dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure to give white crystals. The crystals were recrystallized from ethyl acetate-hexane (1:2.7, 370 mL) to give 87.8 g (89%) of N-benzyloxycarbonyl-DL-phenylalaninol as white crystals.

Provenance & Evidence