(S)-b-AMino-4-chloro-benzeneethanol

67336-19-0

191109-51-0

The general procedure for the synthesis of (S)-2-amino-2-(4-chlorophenyl)ethanol from (S)-4-chlorophenylglycine was as follows: to a solution of (S)-2-amino-2-(4-chlorophenyl)acetic acid (10.0 g, 53.9 mmol) in tetrahydrofuran (THF, 216 mL) was slowly added dropwise to a solution of (S)-2-amino-2-(4-chlorophenyl)acetic acid (10.0 g, 53.9 mmol) in the presence of a 1.0 M borane tetrahydrofuran complex (216 mL. 216 mmol) over 45 min. After removal of the ice bath, the reaction mixture was continued to be stirred at room temperature for 3.25 hours. Subsequently, water (6.79 mL, 377 mmol) was slowly added followed by sodium hydroxide solution (40.4 mL, 202 mmol) dropwise over 15 minutes. The reaction mixture was heated to 65 °C and stirred at this temperature for 18 hours. After completion of the reaction, the solvent was removed by concentration under reduced pressure. The residue was dissolved in dichloromethane (DCM, 500 mL), the organic phase was separated and washed with deionized water (200 mL). The aqueous phase was further extracted with dichloromethane (2 x 250 mL). All organic phases were combined, dried with anhydrous sodium sulfate (Na2SO4) and concentrated under reduced pressure to afford (S)-2-amino-2-(4-chlorophenyl)ethanol as a white solid (8.55 g, 92% yield). The product was characterized by LC-MS and 1H NMR: the calculated exact mass (C8H10ClNO) was 171.1, and the measured LC-MS m/z (%) was 172.2 ([M+H]+, 35Cl, 100) and 174.2 ([M+H]+, 37Cl, 33); 1H NMR (400 MHz, methanol-d4) δ ppm 3.47- 3.57 (m, 1H), 3.59-3.69 (m, 1H), 3.93 (dd, J=7.58,5.05Hz, 1H), 7.23-7.42 (m, 4H).