Synthesis and radiolabelling of Re(CO)3-β-elemene derivatives as potential therapeutic radiopharmaceuticals

beta-Elemene, (1S, 2S, 4R)-(-)-(1-methy-1-vinyl-2,4-diisopropenyl cyclohexane) is an anticancer agent from the Traditional Chinese Herb Medicinal. Three novel Re(CO)(3)-beta-elemene derivatives including their radioactive conjugates containing N,N,N tridentate ligands and tricarbonyl rhenium (complex 12, 13, 14) were synthesized. Their structures were characterized by infrared (IR), H-1-NMR and HRMS. Good radioactive yield (above 90%) and radioactive chemical purity with Re-188 (above 95%) were obtained for all of the three derivatives (complex 15, 16, 17). The anti proliferative activity of non-radioactive beta-elemene-Re(CO)(3) derivatives on Lewis lung cancer cells and HeLa cell lines were evaluated by WST-1 methods. The result shows substantial decrease in IC50 values compared with the parent compound beta-elemene. The synthesis and radiosynthesis of beta-elemene tricarbonyl rhenium conjugates provide the possibility to find a new kind of potential radiopharmaceuticals on beta-elemene.