N2 elimination thermolysis reactions of 9-(4- and 5-substituted-1,2,3-triazol-1-yl)acridines to produce 1H-pyrido-[4,3,2-kl] derivatives – A theoretical study

Abstract

9-azidoacridine reacts under 1,3-dipolar reaction with alkyne derivatives to yield 9-(4- and 5-substituted-1,2,3-triazol-1-yl)acridine derivatives. The extrusion of N2 from these compounds leads to formation of carbene and biradical intermediates. Radical moieties interact with the acridine ring to form 1H-pyrido-[4,3,2-kl] derivatives. The focus of this study was on the theoretical and computational studies of the pathways of the products. The energy levels of the reactant species, TS forms (transition states), products, the free energies of reaction (ΔrG and ΔG#), HOMO & LUMO orbital levels, the ΔEHOMO-LUMO, dipolmoments, rate constants by using Eyring's equation (k and k′), structural data were calculated by DFT (B3LYP/6-31G∗) method. The relative energies (in kcalmol−1) of the transition states as well as the biradical (singlet (S) and triplet (T); and carbene (singlet (S) and triplet (T); intermediates of the pyrolysis reactions on the reactants were investigated as well. The stepwise of the N2 elimination reactions have also investigated. The values of the free activation energy (ΔG#) in the concerted N2 elimination pyrolysis reactions were correlated to the decomposition temperature (TDecom.) of reactants.