In this work, we proposed the synthesis of a series of pyrazoles derivatives with different
substituents on the aromatic rings. We aim to evaluate their influence on the reactivity of the compounds
in reactions of α,β-unsaturated chalcones and sulfonyl hydrazide catalyzed by iodine. In order
to explain their high and low yields, or the impossibility of obtaining some compounds by applied synthetic
methodology, Density Functional Theory (DFT) calculations were performed. The reaction
Gibbs free energy (ΔG) as well as the energy gap of the HOMO-LUMO frontier orbitals (ΔE) of some
selected reactants could explain qualitatively the experimental observations in terms of synthesis yield.
In this way, we believe that the chemical nature of aromatic ring substituents is relevant for the reactivity
of the starting materials as well as the formation of the desired products.