Synthesis of F-18-c(RGDfK) as Integrin alpha(v)beta(3) Targeted PET Tracer via Click Chemsitry with Cu(I) Catalyst Systems

As one of the most important types of Click chemistry, copper-catalyzed 1,3-dipolar cycloaddition reaction has attracted great attention. In this study, 2-[F-18]fluoroethyl azide([F-18]FEA) was synthesized by nucleophilic substitution of F-18(-). Then, [F-18]fluoroethyl-1H-1,2,3-triazole-4-c(RGDfK) [F-18-c(RGDfK)] was radio-synthesized as integrin alpha(v)beta(3), targeted PET tracer fast and efficiently via Click reaction of [F-18]FEA with propioloyl c(RGDfK). Three catalyst systems of click reaction were investigated; CuSO4/NaVc, Cul(s) and CuI/NH2OH, the last two have been used in peptide-click-labeling for the first time. While CuSO4/NaVc catalysing the Click reaction, the total radio-chemistry yield of F-18-c( RGDfK) was 62% and the synthesis time was about 60 min( decay-corrected). Click chemistry has demonstrated to be an extraordinarily efficient and convenient method for the preparation of F-18 labeled peptides.