Figure 4

Modified solid-phase synthesis of the DOTA conjugate 10 [[17]] and DOTAGA conjugates 11 and 12. (a) 20% piperidine in NMP, Fmoc-Phe-OH, HOBt, TBTU, DIPEA, [NMP]; (b) 20% piperidine in NMP, DOTA-tris-t Bu-ester, HATU, DIPEA [NMP]; (c) 95% TFA, 2.5% TIBS, 2.5% H₂O; (d) 20% piperidine in NMP, DOTAGA-anhydride, DIPEA [NMP]; (e) DSS, TEA [DMF]; (f) 7, TEA [DMF]; (g) TFA; (h) 8, TEA [DMF]; (i) 9, TEA [DMF].