2104-89-4

501-53-1

14464-15-4

General procedure for the synthesis of N-Cbz-DL-serine methyl ester from methyl 2-amino-3-hydroxypropionate (19.04 mmol) and benzyl chloroformate: methyl 2-amino-3-hydroxypropionate was dissolved in 34 mL of water. To this solution was added 59.02 mmol (3.1 eq.) of magnesium oxide and 16 mL of ether. The mixture was cooled to 0°C in an ice bath. Under stirring conditions, a 50% solution of benzyl chloroformate dissolved in toluene (9.0 mL) was slowly added and stirred continuously for 2 hours at 0°C. Subsequently, the reaction mixture was slowly warmed to room temperature and stirring was continued for 30 minutes. After completion of the reaction, the mixture was filtered and the filtrate was washed with 2 mL of ether. The aqueous phase was acidified with citric acid to pH ≈ 3 and subsequently extracted with ethyl acetate. The organic phase was dried with anhydrous sodium sulfate. The course of the reaction was monitored by thin layer chromatography (TLC) in a 30% ethyl acetate/hexane and n-butanol:acetic acid:water (3:1:1) system. The final product was a white crystalline solid in 74% yield with a melting point of 116-120°C (literature value: 118-120°C).