Theoretical study of the mechanism and regioselectivity in the formation of pyrazolo[1,5-a]- [1,3,5]-triazines and pyrazolo[1,5-a]-[1,3,5]triazinones: a DFT study

Marwa Manachou (1) , Christophe Morell (2) , Henry Chermette (2) , Salima Boughdiri (1)

1 Research Unity of Physical Chemistry Condensed Materials
2 Chemometrics and theoretical chemistry. - Chimiométrie et chimie théorique

To shed more insight into the regioselectivities observed in the reactions between 3,5-diaminopyrazoles and N-acyl imidates or N-ethoxy imidate yielding the corresponding substituted pyrazolo[1,5-a]-[1,3,5] triazines or pyrazolo[1,5-a][1,3,5] triazinones, DFT calculations are carried out using B3LYP/6- 31++G (d, p) method. The favored mechanism and the experimental regioselectivity of this reaction are rationalized by calculations of activation energy, natural atomic charge, and Fukui indexes derived from density functional theory. The present study shows that the experimental trends of the relative reactivities and regioselectivities of these reactions are correctly predicted using these computational levels.

Mots clés: heterocyclic system; pyrazolotriazine; Transition state; regioselectivity; DFT calculation; Theoretical mechanism; Fukui function

Domaines: Chimie théorique et/ou physique; Chimie

Marwa Manachou, Christophe Morell, Henry Chermette, Salima Boughdiri. Theoretical study of the mechanism and regioselectivity in the formation of pyrazolo[1,5-a]- [1,3,5]-triazines and pyrazolo[1,5-a]-[1,3,5]triazinones: a DFT study. Chemical Physics Letters, 2019, 727, pp.95-104. ⟨10.1016/j.cplett.2019.04.054⟩. ⟨hal-02108912⟩