Functionalization of Glucose at Position C-3 for Transition Metal Coordination:  Organo-Rhenium Complexes with Carbohydrate Skeletons

Abstract

Novel 3-O-[1,2;5,6-di-O-isopropylidene-alpha-D-glucofuranose] and 3-O-[D-glucose] derivatives with an iminodiacetate (N,O,O), a histidinate, and an N-(acetetyl)picolylamine (N,N,O) chelating system for tridentate coordination of the organometallic M(CO)(3)-fragment (M = Tc, Re) have been prepared. The chelates were introduced and assembled through reductive amination starting from 3-O-[1,2;5,6-di-O-isopropylidene-alpha-D-glucofuranose]-acetaldehyde. After deprotection, the pyranose derivatives were reacted with the precursor [NEt(4)](2)[ReBr(3)(CO)(3)] to afford the corresponding organometallic complexes in yields between 54% and 94%. The NMR, MS, and IR analyses corroborated the tridentate coordination of the organometallic metal center exclusively via the synthetic chelates. In the case of the N-(acetyl)picolylamine derivative, the coordinative properties were further confirmed by X-ray structure analysis of the first Re(CO)(3)-D-glucofuranose complex. All glucose complexes unveiled good stability and solubility in organic and aqueous media.

Technetium‐99m radiochemistry for pharmaceutical applications

“…The final product is obtained in two consecutive steps, click and chelate without intermediate purification being required . The (N,O,O) iminodiacetic acid forms an anionic [ 99m Tc(CO) 3 (N,O,O)] − complex (Figure .3), and although its stability is lower, it is less lipophilic …”

“…The final product is obtained in two consecutive steps, click and chelate without intermediate (Figure 16.3), and although its stability is lower, it is less lipophilic. 86,87 (N,S,N) donors include diaminothioether and diaminothiol ligands ( Figure 17). The diaminothioether ligands yield cationic [ 99m Tc(CO) 3 Figures 16.4 and 17).…”

Metal-based glycoconjugates and their potential in targeted anticancer chemotherapy

“…Schibli and co-workers generated a series of technetium-99m (and the corresponding "cold" rheniumbased analogues) tricarbonyl complexes bearing different tridentate chelating moieties (including iminodiacetate, N-(2-pyridylmethyl)glycine and N aliphatic -tethered histidine) bound to glucose at the C(1), C(2), C(3) and C(6) position [167,168]. All complexes showed high stability in vitro but cellular uptake proved rather low and not mediated by a GLUT1-dependent process.…”

Rhenium and technetium complexes that bind to amyloid-β plaques

“…4). [26][27][28][29][30][31] This is possibly due to the inclusion of a six membered chelate ring instead of two five membered chelate rings seen in other complexes with the same donor atom set. In fac-[Re I (CO) 3 L 1 ], the remaining coordination sphere of the metal is completed by an NNO donor atom set provided by the pyridyl nitrogen, tertiary amine and carboxylate groups of the ligand.…”