Propanoic acid, 3-[[(1,1-dimethylethoxy)carbonyl]amino]-2-hydroxy-, (2S)-

565-71-9

24424-99-5

52558-24-4

(S)-Isoserine (21 g, 0.20 mol) was dissolved in tetrahydrofuran (100 mL), followed by addition of a solvent mixture of 10% aqueous sodium hydroxide (100 mL) and di-tert-butyl dicarbonate (50 mL, 0.22 mol). The reaction mixture was stirred at room temperature for 9 hours. After completion of the reaction, the aqueous phase was adjusted to pH 2 with 4 mol/L hydrochloric acid and then extracted with dichloromethane/methanol (v/v=5/1, 50 mL x 3). The organic phases were combined and dried with anhydrous sodium sulfate. After drying, the desiccant was removed by filtration and the filtrate was concentrated under reduced pressure to give 3-tert-butoxycarbonylamino-(S)-2-hydroxypropionic acid as a colorless oil (35 g, yield: 85%).