(S)-11-Benzyl-1-(9H-fluoren-9-yl)-3,6,9,12,15-pentaoxo-2,18-dioxa-4,7,10,13,16-pentaazaicosan-20-oic acid

(S)-11-Benzyl-1-(9H-fluoren-9-yl)-3,6,9,12,15-pentaoxo-2,18-dioxa-4,7,10,13,16-pentaazaicosan-20-oic acid,