Efficient and Site-Specific 125 I-Radioiodination of Bioactive Molecules Using Oxidative Condensation Reaction.

In this report, the novel and site-specific radioiodination of biomolecules by using aryl diamine and alkyl aldehyde condensation reaction in the presence of a Cu catalyst under ambient conditions was reported. I-labeled alkyl aldehyde was synthesized using a tin precursor with a high radiochemical yield (72 ± 6%, = 5) and radiochemical purity (>99%). The utility of the radioiodinated precursor was demonstrated through aryl diamine-installed c[RGDfK(C)] peptide and human serum albumin (HSA). Radioiodinated c[RGDfK(C)] peptide and HSA protein were synthesized with high radiochemical yields and purity. I-HSA protein showed excellent stability and negligible thyroid uptake as compared with directly radioiodinated HSA by using the tyrosine group. Excellent reaction kinetics and the and stabilities of I-labeled alkyl aldehyde have suggested the usefulness of the strategy for the radioiodination of bioactive molecules.