Synthesis
To a three-necked flask equipped with a mechanical stirrer, reflux condenser, thermometer and under nitrogen protection was added L-alanine (5.0 g, 56.1 mmol) and 11.1% w/w solution of isopropanol hydrochloride (73.8 g, 224.5 mmol). The reaction mixture was heated to 80-85 °C for 4 h at reflux. The reaction process was monitored by thin layer chromatography (TLC) using 7:3 ethanol-water as the unfolding agent and ninhydrin for color development. Upon completion of the reaction, the reaction mixture was concentrated under reduced pressure to remove isopropanol and the residue was co-evaporated with isopropyl acetate several times to give the final product (R)-isopropyl 2-aminopropionate hydrochloride in oil form (9.4 g, quantitative yield).
References
[1] Patent: WO2016/151542, 2016, A1. Location in patent: Page/Page column 19
[2] European Journal of Organic Chemistry, 2018, vol. 2018, # 20, p. 2622 - 2628
[3] ACS Medicinal Chemistry Letters, 2016, vol. 7, # 12, p. 1197 - 1201
[4] Patent: WO2015/38596, 2015, A1. Location in patent: Page/Page column 237; 238
[5] Patent: WO2016/145142, 2016, A1. Location in patent: Page/Page column 287