(R)-2-phthalimidobutyric acid

(1'S,5R)-1-(benzyloxycarbonyl)-3-(1'-phenyleth-1'-yl)-5-ethylimidazolidin-4-one

(R)-2-((phenylsulfonyl)amino)butyric acid

N-Chloroacetyl-D-α-aminobutyric acid

1-methyl-(3R)-ethyl-4-((S)-α-phenylethyl)-1,4-benzodiazepine-2,5-dione