(S)-2-((((9H-Fluoren-9-yl)methoxy)carbonyl)amino)-4-((2,2,10,10-tetramethyl-4,8-dioxo-3,9-dioxa-5,7-diazaundecan-6-ylidene)amino)butanoic acid

(S)-2-((((9H-Fluoren-9-yl)methoxy)carbonyl)amino)-4-((2,2,10,10-tetramethyl-4,8-dioxo-3,9-dioxa-5,7-diazaundecan-6-ylidene)amino)butanoic acid