Improved synthesis of no-carrier-added [*I]MIBG and its precursor

Abstract

3-(Trimethylstannyl)benzyl alcohol was coupled in a Mitsunobu reaction with bis(Boc)-guanidine to give bis(Boc)-protected 3-(trimethylstannyl) benzylguanidine used as precursor for [*I]MIBG. Radioiodination with [ 131I]iodine generated from [ 131I]NaI and chloramine-T, removal of Boc groups, and purification by HPLC gave no-carrier-added tracer [*I]MIBG (81% radiochemical yield, 99% chemical purity) used for imaging tumors of neuroendocrine origin. The structures of bis(Boc)-guanidine and bis(Boc)-protected 3-(trimethylstannyl)benzylguanidine were secured by single crystal X-ray structure analyses.