ABSTRACT
In this paper we describe the design and synthesis of bis(Het)Aryl-1,2,3-triazole quinuclidine α7R ligands using an efficient three-step sequence including a Suzuki-Miyaura cross coupling reaction with commercially available and home-made boron derivatives. The exploration of SAR required the preparation of uncommon boron derivatives. Forty final drugs were tested for their ability to bind the target and nine of them exhibited Ki values below nanomolar concentrations. The best scores were always obtained when the 5-phenyl-2-thiophenyl core was attached to the triazole. The selectivity of these compounds towards the nicotinic α4ß2 and serotoninergic 5HT3 receptors was assessed and their brain penetration was quantified by the preparation and in vivo evaluation of two [18F] radiolabelled derivatives. It can be expected from our results that some of these compounds will be suitable for further developments and will have effects on cognitive disorders.
Subject(s)
Brain/diagnostic imaging , Cognition Disorders/drug therapy , Fluorine Radioisotopes/chemistry , Isotope Labeling , Nicotinic Agonists/pharmacology , Positron-Emission Tomography , Quinuclidines/pharmacology , Triazoles/pharmacology , alpha7 Nicotinic Acetylcholine Receptor/agonists , Animals , Brain/metabolism , Cell Survival/drug effects , Cognition Disorders/metabolism , Dose-Response Relationship, Drug , Ligands , Molecular Structure , Nicotinic Agonists/chemical synthesis , Nicotinic Agonists/chemistry , Quinuclidines/chemical synthesis , Quinuclidines/chemistry , Rats , Rats, Wistar , Structure-Activity Relationship , Triazoles/chemical synthesis , Triazoles/chemistry , Tumor Cells, Cultured , alpha7 Nicotinic Acetylcholine Receptor/metabolismABSTRACT
The combined use of Tf2NH and L(Au)(+)X(-) as a dual or binary catalytic system clearly improves the efficiency and enlarges the scope of the tandem intermolecular Friedel-Crafts α-amidoalkylation/intramolecular hydroarylation sequence, compared to an "all gold" multicatalysis approach.
ABSTRACT
Gold catalysts have been applied in cascade-type reactions for the synthesis of different nitrogen-based compounds. The reactions likely proceed by a new gold-catalyzed cascade intermolecular α-amidoalkylation/intramolecular carbocyclization cascade process by unifying both the σ- and π-Lewis acid properties of the gold salts. In the first part of this report we show that the σ-Lewis acidity of gold(I) and gold(III) could be exploited to efficiently catalyze the nucleophilic substitution of various alkoxy- and acetoxylactams. The reaction was found to be applicable to a wide range of cyclic N-acyliminium ion precursors and various nucleophiles, including allyltrimethylsilane, silyl enol ethers, arenes, and active methylene derivatives. As a logical progression of this study, a combined hard/soft binary catalytic gold system was then used to implement an unprecedented tandem intermolecular Friedel-Crafts amidoalkylation/intramolecular hydroarylation sequence allowing an expedient access to new, complex, fused polyheterocyclic structures from trivial materials.
