ethyl 3-((3S,4S)-1-benzyl-4-(((R)-1-phenylethyl)amino)pyrrolidin-3-yl)propanoate

ethyl 1-benzyl-3-(3-ethoxy-3-oxopropyl)-4-oxopyrrolidine-3-carboxylate

(2R,3S)-2-(benzylcarbamoyl)-1-((R)-2-hydroxy-1-phenylethyl)-6-oxopiperidine-3-carboxylic acid

(4R)-1,6-dioxo-4-phenyl-1,3,4,6,7,8-hexahydropyrido[2, 1-c][1,4]oxazine-9-carboxylic acid methyl ester