Synthesis
Step 1: Preparation of methyl (2S)-2-aminobutyrate; (2S)-2-aminobutyric acid (21.56 g, 0.21 mol) was dissolved in 120 mL of methanol. The reaction mixture was cooled to 0°C in an ice-water bath and thionyl chloride (30.5 mL, 0.42 mol) was added slowly and dropwise with continuous stirring. After the dropwise addition, the reaction mixture was heated to reflux for 2 hours and subsequently cooled to room temperature. The solvent was removed by concentration under reduced pressure to afford methyl (2S)-2-aminobutyrate (31.87 g, 99.3% yield) as a white solid.
References
[1] Patent: EP2481739, 2012, A1. Location in patent: Page/Page column 78
[2] Patent: US2012/184543, 2012, A1. Location in patent: Page/Page column 79
[3] Patent: WO2009/23655, 2009, A1. Location in patent: Page/Page column 53
[4] Journal of the American Chemical Society, 1991, vol. 113, # 11, p. 4297 - 4303
[5] Justus Liebigs Annalen der Chemie, 1961, vol. 649, p. 183 - 202
