A combined experimental and theoretical study
of the thermal cycloaddition of aryl azides with activated alkenes
Sarah Zeghada,aGheniaBentabed-Ababsa,*a,bA¨ıchaDerdour,aSafer Abdelmounim,aLuis R. Domingo,*cJos´e A. S´aez,cThierry Roisnel,dEkhlassNassar e and Florence Mongin* Organic &Biomolecular Chemistry, 2011, 9, 4295(The Royal Society of Chemistry 2011) (England).
Abstract
Reactions were performed from aryl azides on the one hand, and activated alkenes coming from b-dicarbonyl compounds or malonodinitrile on the other hand, either with recourse to conventional heating or to microwave activation, to afford 1-aryl-1H-1,2,3-triazoles. The mechanism and the regioselectivity of the reactions involving b-dicarbonyl compounds have been theoretically studied using DFT methods at the B3LYP/6-31G* level: they are domino processes comprising a tautomeric equilibrium of the b-dicarbonyl compounds with their enol forms, a 1,3-dipolar cycloaddition of the enol forms with the aryl azides (high activation energy), and a dehydration process (lower activation energy). The effect of non-conventional activation methods on the degradation of 1,2,3-triazolines was next studied experimentally. Finally, some of the 1,2,3-triazoles such synthesized were evaluated for their bactericidal and cytotoxic activities.
