Benzaldehyde → (R)-2-(Benzylamino)-3-hydroxypropanoic acid

Participants

Reaction Steps

To a stirred solution of D-serine (14.7 g, 140.0 mmol) in aqueous 2M NaOH (70 mL) was added benzaldehyde (14.6 g, 14.0 mL, 138.0 mmol). The reaction mixture was then stirred at r.t. for 1 h before cooling to 5° C. NaBH4 (1.5 g, 40.0 mmol) was added portionwise such that an internal temperature of between 6 and 10° C. was maintained. After addition, the reaction mixture was allowed to stir at 5° C. for 30 minutes and then at r.t. for 1 h. The reaction mixture was cooled to 5° C. and a further portion of NaBH4 (1.5 g, 40.0 mmol) was added portionwise such that an internal temperature of <10° C. was maintained. The ice bath was removed on completion of addition and the reaction mixture stirred at r.t. for 16 h. The reaction mixture was then extracted with Et2O (3×100 mL) and the aqueous phase acidified to pH 5 with conc. HCl. The resultant white precipitate was filtered and washed with water. The product was dried in vacuo to give the title compound (24.0 g, 88%) as a white solid. δH (DMSO-d6) 7.45-7.30 (5H, m), 4.04-3.91 (2H, m), 3.70-3.61 (3H, m), 3.17 (1H, t, J 5.8 Hz).

Provenance & Evidence