While important efforts were made in the development of positron emission tomography (PET) tracers for the in vivo molecular diagnosis of Alzheimer's disease, very few investigations to develop magnetic resonance imaging (MRI) probes were performed. Here, a new generation of Gd(III)-based contrast agents (CAs) is proposed to detect the amyloid β-protein (Aβ) aggregates by MRI, one of the earliest biological hallmarks of the pathology. A building block strategy was used to synthesize a library of 16 CAs to investigate structure-activity relationships (SARs) on physicochemical properties and binding affinity for the Aβ aggregates. Three types of blocks were used to modulate the CA structures: (i) the Gd(III) chelates (Gd(III)-DOTA and Gd(III)-PCTA), (ii) the biovectors (2-arylbenzothiazole, 2-arylbenzoxazole and stilbene derivatives) and (iii) the linkers (neutrals, positives and negatives with several lengths). These investigations revealed unexpected SARs and a difficulty of these probes to cross the blood-brain barrier (BBB). General insights for the development of Gd(III)-based CAs to detect the Aβ aggregates are described.
Amide formation O 0325Microwaves-Assisted Solvent-Free Synthesis of N-Acetamides by Amidation or Aminolysis. -Improved microwave-promoted conditions are developed: an by the aid of low wattage microwave irradiation acetamides can be advantageously synthesized from acetic acid or vinyl acetate and amines. -(FERROUD*, C.; GODARD, M.; UNG, S.; BORDERIES, H.; GUY, A.; Tetrahedron Lett. 49 (2008) 18, 3004-3008; Lab. Transform. Chim. Pharm., Cons. Natl. Arts Metiers, CNRS, F-75003 Paris, Fr.; Eng.) -Mais 33-054
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