Syntheses and First Crystal Structures of Rhenium Complexes Derived from ψ-Functionalized Fatty Acids as Model Compounds of Technetium Tracers for Myocardial Metabolism Imaging

Abstract

In an attempt to develop new technetium-based radiopharmaceuticals for the noninvasive diagnosis of myocardial metabolism, we have synthesized three examples of novel metal-containing fatty acid derivatives according to the ''3+1'' mixed-ligand and the Schiff base/tricarbonyl design. The chelates contain the metal core in the oxidation states +5 and +1, respectively, and are attached to the end-position of a fatty acid chain. The complex formation was accomplished by ligand-exchange reactions with three different rhenium

Carbonyl complexes of manganese, rhenium and molybdenum with 2-pyridylimino acid ligands

“…GABA is an important inhibitor which acts in a wide variety of biological processes, whereas b-alanine, the simplest b-amino acid (and the only one occurring naturally) is believed to be involved in the visual system [17] and, together with GABA, to act as a neurotransmitter in the central nervous system [18]. A series of complexes of the W(CO) 4 fragment containing iminopyridines derived from 3-aminobenzoic acid [19] and a series of amino acids and dipeptides [20] have been recently reported, as well as the bromo tricarbonyl rhenium iminopyridine derivative of x-amino undecanoic acid [21].…”

Myocardial uptake and biodistribution of newly designed technetium-labelled fatty acid analogues

“…The synthesis of the '3 + 1' and '4 + 1' mixed-ligand complexes has been published recently [11][12][13][14][15][16]. The preparation of the '3 + 1' 99m Tc complexes follows a onestep procedure as described before [13], with reduction of the pertechnetate with stannous(II) chloride, in the presence of the monodentate FA thiol and the tridentate ligand of choice, with propylene glycol as a co-solvent.…”

“…Furthermore, a thioether sulfur was inserted into the alkyl chain, blocking further metabolic conversion, e.g., via b-oxidation. A detailed description of the ligand synthesis, the preparation of the corresponding non-radioactive rhenium model complexes and the physico-chemical characterization (nuclear magnetic resonance (NMR), elemental analysis and X-ray structures) has been published previously [12,16].…”

“…Because working with radioactive compounds requires great care and is subjected to some restrictions, the thirdrow congener rhenium was used in preliminary studies as a surrogate for the radioactive 99m Tc nuclide [12].…”

Synthesis and characterization of polyamidoamine dendrimers surface-functionalized with bromotricarbonylpyridyliminerhenium(I) units

“…Nheterocycles are known to form strong bonds to Re(I) metal centers [19][20][21][22][23][24]. Comparatively, there are few reports of rhenium containing dendrimers.…”