521284-19-5

611-71-2

29968-78-3

521284-19-5

GENERAL STEPS: To a stirred solution of (R)-mandelic acid (97.61 g) in acetonitrile (1000 mL) was slowly added trimethyl borate (66.66 g) at 28 °C (±2 °C). After addition, the reaction system was warmed to 58 °C (±2 °C) and maintained for 90 min. Maintaining this temperature, 4-nitrophenylethylamine hydrochloride (100.0 g) was added to the reaction solution. Subsequently, N,N-diisopropylethylamine (82.92 g) was added slowly and the reaction mixture was heated to reflux for 12 hours. After completion of the reaction, the system was cooled to 30 °C (±2 °C) and diluted with ethyl acetate (1100 mL) and 1 M aqueous hydrochloric acid (1400 mL). The organic phase was separated and washed with 1M aqueous hydrochloric acid solution, 5% aqueous sodium hydroxide solution and saturated saline in turn. The organic phase was concentrated under reduced pressure and the residue was recrystallized from toluene (500 mL). The resulting solid was washed with toluene and dried under vacuum at 48 °C (±2 °C) to give the light yellow crystalline product (R)-2-hydroxy-N-[2-(4-nitrophenyl)ethyl]-2-phenylacetamide. Yield: 125 g (84.3%); HPLC purity: 98.65%.