Benzaldehyde → (2S)-2-(benzylamino)-3-hydroxypropanoic acid

Temperature

5 °C

Racemic serine (14.7 g, 140 mmol) was dissolved in 2M NaOH (70 mL) and benzaldehyde (14.64 g, 14.0 mL, 138 mmol) added with stirring. The mixture was stirred at r.t. for 1 h before cooling to 5° C. Sodium borohydride (1.5 g, 40 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 sodium borohydride (1.5 g, 40 mmol) added portionwise such that an internal temperature <10° C. was maintained. The ice bath was removed on completion of addition and the reaction stirred at r.t. for 16 h. The reaction mixture was extracted with Et2O (3×100 mL) and the aqueous phase acidified to pH 5 with concentrated hydrochloric acid. 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%). 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). Some exchangeable protons were not observed.

1. stirringThe mixture was stirred at r.t. for 1 h
2. temperaturewas maintained
3. additionAfter addition the reaction mixture
4. stirringto stir at 5° C. for 30 minutes
5. temperatureThe reaction mixture was cooled to 5° C.
6. temperaturewas maintained
7. customThe ice bath was removed on completion of addition
8. stirringthe reaction stirred at r.t. for 16 h
9. extractionThe reaction mixture was extracted with Et2O (3×100 mL)
10. filtrationThe resultant white precipitate was filtered
11. washwashed with water
12. customThe product was dried in vacuo

ORD record

ord-7e188438f57f4697a1313480dc78a108

Source dataset

uspto-grants-2011_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07888344B2