A practical protocol for large ‐scale copper‐mediated radioiodination of organoboronic precursors: Radiosynthesis of [123I]KX‐1 for Auger radiotherapy

Neutralization of the strong basic solution of [123]NaI/NaOH with an acid (pyridiniump-toluenesulfonate) promotes the radiosynthesis of [123I]KX-1 on large-scale via copper-mediated radioiodination (CMRI) of the organoboronic precursor in high radiochemical yield, high radiochemical purity, and high molar activity. This strategy should be applicable to the radiosynthesis of other radioiodine-labeled compounds via CMRI. Nucleophilic copper-mediated radioiodination (CMRI) of organoboronic precursors with radioiodides is a promising method of radioiodination. The previously reported CMRI has demonstrated its great potential and scope of labeling for the radiosynthesis of radioiodine-labeled compounds. However, the reported protocols (using a small amount/volume of radioactivity) are practically not reproducible in large-scale CMRI, in which the radioactivity was usually provided in a bulk alkaline solution. A large amount of water and a strong base are incompatible with CMRI. To overcome these issues in large-scale CMRI, we have developed a simple protocol for large-scale CMRI. The bulk water was removed under a flow of inert gas at 110 °C, and the strong base (i.e., NaOH) was neutralized with an acid, pyridiniump-toluenesulfonate orp-toluenesulfonic acid. In the model reactions of [123I]KX-1, a PARP-1 radioligand for Auger radiotherapy, radiochemical conversions were significantly improved after neutralization of the base, and the addition of additional acids was tolerated and...

Source: Journal of Labelled Compounds and Radiopharmaceuticals - September 22, 2023 Category: Biochemistry Authors: Dong Zhou, Wenhua Chu, Jinbin Xu Tags: NOTE Source Type: research