(S)-21,39-Di-tert-butyl 1-(2,5-dioxopyrrolidin-1-yl) 9,18,23-trioxo-2,5,11,14-tetraoxa-8,17,22-triazanonatriacontane-1,21,39-tricarboxylate
(S)-22-(tert-Butoxycarbonyl)-43,43-dimethyl-10,19,24,41-tetraoxo-3,6,12,15,42-pentaoxa-9,18,23-triazatetratetracontanoic acid
