A new bifunctional chelating ligand based on glucosamine for the [M(CO)₃]⁺ (M=Tc, Re) core

• Main Author: Ewart, Charles Bethune
• Language: English
• Published: 2010
• Online Access: http://hdl.handle.net/2429/17957

The development of a SPECT (single photon emission computed tomography) carbohydrate analogue for FDG (2-deoxy-2-[¹⁸F]fluoro-D-glucose), used in PET (positron emission tomography), is of great interest in the scientific community. The great utility of FDG suggests that other radiolabelled carbohydrates may be medicinally useful compounds. PET is expensive and not readily available, due to the inherent short half-lives and cyclotron production of the positron emitters. SPECT allows for the use of common radionuclides such as ⁹⁹mTc, which is the most widely used radioisotope in nuclear medicine because of its near ideal imaging properties. This work describes the synthesis and characterization of a carbohydrate-appended tridentate ligand (HL2) designed for the [M(CO)₃]⁺ (M = Tc, Re) core. This core is synthetically useful because it is small, robust, and will afford a neutral complex with the monoprotic HL2 ligand. The complexation to produce the corresponding complexes M(L2)(CO)₃ (M = Tc, Re) was also undertaken, and Re(L2)(C O)₃ was characterized via ¹H and ¹³C NMR spectroscopy, IR spectroscopy, mass spectrometry, and elemental analysis. Kit preparation of the precursor [⁹⁹mTc(CO)₃(H₂O)₃]⁺ species for radiotracer studies is well documented, and the cation can be prepared in high yield with excellent radiochemical purity. Labelling studies to produce ⁹⁹mTc(L2)(CO)₃ indicated high radiolabelling yields, as determined by HPLC methods. Challenge experiments with aqueous solutions of cysteine and histidine indicate strong tridentate binding of HL2 to the metal centres. === Science, Faculty of === Chemistry, Department of === Graduate