Step B. Synthesis of 4-benzylmorpholine-2-carboxylic acid. 4-Benzylmorpholine-2-carbonitrile (20.2 g, 100 mmol) was dissolved in toluene (60 mL), followed by the slow addition of 6 M hydrochloric acid solution (100 mL, 600 mmol). The reaction mixture was heated to 110 °C and kept at reflux for 1.5 hours. Upon completion of the reaction, the mixture was cooled to room temperature and stirring was continued for 18 hours. The precipitated solid was collected by filtration to afford the target product 4-benzyl-morpholine-2-carboxylic acid (22 g, 99% yield) as a white solid.
