Abstract:We describe herein an efficient protocol to synthesize selanyl-substituted pyrazoles by cyclocondensation and copper-catalyzedd irect C À H bond selenation reactions.T he products were obtained in moderate to excellent yields by the onepot multicomponent reactions of hydrazines,1 ,3-diketones andd iorganyl diselenides,u sing catalytic amounts of copper bromidea nd bipyridine.T hese reactions tolerated ar ange of substituents in the starting materials and provedt ob ea nefficient methodologyf or combinatorial synthesis of news elenium-containing pyrazoles with potentiala pplications in biological studies.

We describe our results on the synthesis of fused 1,2,3‐triazolo‐1,3,6‐triazonines through a copper‐catalyzed multicomponent reaction. The products were obtained in moderate to excellent yields by the reaction of 2‐azidobenzaldehydes, substituted diaminobenzenes and a range of terminal alkynes in the presence of a catalytic amount of copper iodide, with Et3N as base, in DMSO at 100 °C. This method proved to be efficient for the combinatorial synthesis of new medium‐sized N‐heterocyclic rings with potential applications in biological studies.

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The synthesis of 2′-(1,2,3-triazoyl)-acetophenones by a CuAAC using thiourea as a ligand, molecular docking and MAO activity analyses were performed.

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We described here our results on the use of thiourea as a ligand in the copper catalysed azide‐alkyne cycloaddition (CuAAC) of 2‐azidobenzaldehyde with alkynes. Reactions were performed reacting 2‐azidobenzaldehyde with a range of terminal alkynes using 10 mol % of copper iodide as a catalyst, 20 mol % of thiourea as a ligand, triethylamine as base, DMSO as solvent at 100 °C under nitrogen atmosphere. The corresponding 2‐(1H‐1,2,3‐triazoyl)‐benzaldehydes (2‐TBH) were obtained in moderated to excellent yields and according our experiments, the use of thiourea decreases the formation of side products. The obtained compounds were screened for their binding affinity with multiple therapeutic targets of AD by molecular docking: β‐secretase (BACE), glycogen synthase kinase (GSK‐3β) and acetylcholinesterase (AChE). The three compounds with highest affinity, 5 a (2‐(4‐phenyl‐1H‐1,2,3‐triazol‐1‐yl)benzaldehyde), 5 b (2‐(4‐(p‐tolyl)‐1H‐1,2,3‐triazol‐1‐yl)benzaldehyde), and 5 d (2‐(4‐(4‐(tert‐butyl)phenyl)‐1H‐1,2,3‐triazol‐1‐yl)benzaldehyde) were selected and evaluated on its antioxidant effect, in view of select the most promising one to perform the in vivo validation. Due the antioxidant potential ally to the affinity with BACE, GSK‐3β and AChE, compound 5 b was evaluated in a mouse model of AD induced by intracerebroventricular injection of streptozotocin (STZ). Our results indicate that 5 b (1 mg/kg) treatment during 20 days is able to reverse the cognitive and memory impairment induced by STZ trough the modulation of AChE activity, amyloid cascade and GSK‐3β expression.

This study demonstrates the facile preparation and use of alginate–Cu2+ microspheres in the catalysis of a new class of organoselenium substituted pyrazoles through one-pot reactions.