In an effort towards the visualization of b-amyloid (Ab) plaques by T1-weighted magnetic resonance imaging for detection of Alzheimer’s disease, we report the synthesis and characterization of stable, noncharged Gd3? complexes of three different 1,4,7,10- tetraazacyclododecane-1,4,7-triacetic acid monoamide derivatives conjugated to Pittsburgh compound B, a wellestablished marker of Ab plaques. The ligands L1, ...
Due to its favorable relaxometric properties, Mn2+ is an appealing metal ion for magnetic resonance imaging (MRI) contrast agents. This paper reports the synthesis and characterization of three new triazadicarboxylate-type ligands and their Mn2+ chelates (NODAHep, 1,4,7-triazacyclononane-1,4-diacetate-7-heptanil; NODABA, 1,4,7-triazacyclononane-1,4-diacetate-7-benzoic acid; and NODAHA (1,4,7-triazacyclononane-1...
A novel synthetic methodology for preparing amide conjugates of the DO3A-N-(alfa-amino)propionate chelator is described, using the synthesis of the DO3A-N-(alfa-benzoylamido)propionate chelator as an illustrative example. The model Gd(DO3A-N-(alfa-benzoylamido)propionate) chelate displays accelerated water exchange, stability in a wide pH range and inertness towards transmetallation by Zn2+. The Gd(DO3A-N-(al...
Gd3L is a trinuclear Gd3+ complex of intermediate size, designed for contrast agent applications in high field magnetic resonance imaging (H12L is based on a trimethylbenzene core bearing three methylene-diethylenetriamine- N,N,NPrimeNPrime-tetraacetate moieties). Thanks to its appropriate size, the presence of two inner sphere water molecules and a fast water exchange, Gd3L has remarkable proton relaxivities a...
The recently reported amphiphilic chelate, [Gd(EPTPAC16)(H2O)]2-, forms supramolecular aggregates in aqueous solution by self-assembly of the monomers with a relaxometrically determined critical micellar concentration (CMC) of 0.34 mM. The effect of sonication on the aggregate size was characterized by dynamic light scattering and relaxometry, indicating the presence of premicellar aggregates and an overall dec...
The synthesis and characterization of a new metal chelator, 4-(S)-hydroxymethyl-3,6,10-tri(carboxymethyl)-3,6,10-triazadodecanedioic acid (H5EPTPACH2OH), is reported. Protonation constants for the ligand H5EPTPACH2OH and for the previously reported H5EPTPAC16 have been determined by potentiometry, which reveals that both ligands display slightly higher protonation constants relative to that of the ligand DTPA5-...
We report the synthesis and characterization of the novel ligand H5EPTPA-C16 ((hydroxymethylhexadecanoyl ester)ethylenepropylenetriaminepentaacetic acid). This ligand was designed to chelate the GdIII ion in a kinetically and thermodynamically stable way while ensuring an increased water exchange rate (kex) on the GdIII complex owing to steric compression around the water-binding site. The attachment of a palmi...
In this paper we report the synthesis and the characterization of the novel ligand H5EPTPA-C16 ((hydroxymethylhexadecanoyl ester)ethylenepropylenetriaminepentaacetic acid). This ligand was designed to chelate the GdIII ion in a kinetically and thermodynamically stable way while ensuring an increased water exchange rate (kex) on the GdIII complex due to steric compression around the water binding site. The attac...
The synthesis and characterisation of a new class of DTPA bis(amide) linked glycoconjugates of different sugars [lactose (Lac) and galactose (Gal)] and valencies (di and tetra) and their LnIII complexes is reported. The 1H NMR spectra of the SmIII and EuIII complexes of DTPAGal2, DTPAGal4, and DTPALac2, obtained between 7 and 80 °C, indicate that several of the four possible diastereoisomeric pairs of structure...
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