(2R,4S)-4-Amino-5-(biphenyl-4-yl)-2-methylpentanoic Acid Ethyl Ester Hydrochloride is used as a reagent in the synthesis of LCZ696, an angiotensin II receptor and neprilysin receptor dual inhibitor. (2R,4S)-4-Amino-5-(biphenyl-4-yl)-2-methylpentanoic Acid Ethyl Ester Hydrochloride is also used as a reagent in the preparation of novel NEP inhibitor prodrugs for the treatment of hypertension and cardiovascular diseases.