Synthesis and Stability Evaluation of New HYNIC Derivatives as Ligands for Technetium-99m

An efficient synthetic route to prepare two new HYNIC derivatives with a 2-nitroimidazole moiety designed for tumor hypoxia imaging is described. During the course of the synthesis, the optimization of N-alkylation reaction of 2- nitroimidazole with propargyl bromide is reported to favor the formation of the terminal alkyne versus allene. Thereafter, the two ligands were used with tricine/EDDA to complex 99mTc. However, decomposition of these ligands was observed and we suggest a reasonable explanation based on LC-MS analysis. Keywords: Technetium-99m, HYNIC, 2-nitroimidazole, tumor hypoxia, imaging, stability evaluation.