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The synthesis of tris-allyl-DOTA starting from cyclen and its application in the preparation of DOTA–peptide conjugates is reported. Clinically important conjugates such as DOTA–Tyr3-octreotide (DOTA–TOC), DOTA–Tyr3-octreotate (DOTA–TATE) as well as a DOTA–RGD peptide were synthesized in high yields with Fmoc solid phase peptide synthesis. The final, extremely reliable de-allylation was achieved on solid phase by different methods identifying morpholine/Pd(0) as the most suitable one obtaining all DOTA peptide conjugates in high yields. All DOTA–peptides were purified by reversed phase HPLC and structural identity was proved using MALDI-TOF mass spectrometry.

A novel Tyr 3 -octreotate conjugated closo -carborane as a potential compound for boron neutron capture therapy was obtained via Fmoc solid phase peptide synthesis. The boron cluster [C 2 B 10 H 11 ] was introduced through the reaction of 6,9-bis(acetonitrile)decaborane and 5-hexynoic acid yielding a new closo -carborane conjugated carboxylic acid which was coupled subsequently with solid phase conjugated Tyr 3 -octreotate. The final boron-containing peptide was purified by preparative reverse phase HPLC and structural identity was proved applying MALDI-TOF mass spectrometry.