Total solid-phase synthesis of NOTA-functionalized peptides for PET imaging.

A convenient approach to functionalize peptides either at the N-terminal or on a lysine side chain with 1,4,7-triazacyclononane-N,N',N''-triacetic acid (NOTA) chelating unit has been developed on solid support. The chelate was assembled in a two-step process starting with bromo-acetylated peptides. Deprotection and cleavage of the resin-bound NOTA peptides were performed with use of trifluoroacetic acid (TFA) in the presence of thioanisole and water to give free NOTA peptides.