Not less than-95.0%
((R)-1-ethoxy-1-oxopentan-2-yl)-D-alanine; (R)-N-(1-Carboxyethyl)-D-norvaline 1-Ethyl Ester; (R)-2-(((R)-1-Ethoxy-1-oxopentan-2-yl)amino)propanoic Acid; N-[(1R)-1-Carboxyethyl]-D-norvaline 1-Ethyl Ester