DL-O-Methylserine → O-Methyl-D-serine

Participants

Reaction Conditions

Reaction Steps

Into a 250 mL round-bottomed flask equipped with a stirrer, reflux condenser and thermometer was added O-methyl-D,L-serine (5 g) in ethanol (150 mL). N-Acetyl-(R)-naphthylalanine (10.80 g) was added in one portion and the mixture heated to 50° C. overnight. The suspension was cooled to room temperature and filtered, and the solid was rinsed with ethanol (5 mL) and dried at 40° C. under vacuum for 3 h. Crude N-acetyl-(R)-naphthylalanine salt of O-methyl-D-serine (6.4 g, 40.5%) was obtained as a white solid with a chiral purity >90%. A portion (5 g) of this solid was suspended in ethanol (30 mL), heated to 50° C. for 4 h, cooled to room temperature and filtered. The resulting solid was rinsed with ethanol (5 mL) and dried at 40° C. under vacuum for 3 h. Pure N-acetyl-(R)-naphthylalanine salt of O-methyl-D-serine (4.6 g, 91.5%) was obtained as a white solid with a chiral purity >95%. Regeneration of the title compound could be effected by adjustment of the pH to 1-2 by treatment with HCl, followed by extraction into an organic solvent and subsequent adjustment of the pH to ˜7 with NaOH.

Provenance & Evidence