(S)-4-((((9H-Fluoren-9-yl)methoxy)carbonyl)amino)-2-((1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl)amino)butanoic acid

(S)-4-((((9H-Fluoren-9-yl)methoxy)carbonyl)amino)-2-((1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl)amino)butanoic acid