(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)-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