149690-12-0

1012341-50-2

149690-12-0

The general procedure for the synthesis of ethyl (2R,4S)-5-([1,1'-biphenyl]-4-yl)-4-[(tert-butoxycarbonyl)amino]-2-methylpentanoate hydrochloride using (2R,4S)-5-([1,1'-biphenyl]-4-yl)-4-amino-2-methylpentanoic acid (1.91 g, 5.0 mmol) as the raw material is as follows: the raw material was added into a reaction flask with ethanol (20 mL). Thionyl chloride (0.41 mL, 5.5 mmol) was slowly added dropwise at 60 °C, and the reaction was continued for 1 h after completion of the dropwise addition. The reaction was confirmed by HPLC. After completion of the reaction, the reaction solution was concentrated under reduced pressure to obtain the target compound (II) (1.67 g, 96.5% yield).