1415320-96-5Relevant academic research and scientific papers
Synthesis and theoretical study of a series of 3,5-disubstitutes pyrazoles
Branco, Ana Clara Alves,Couri, Mara Rubia Costa,Enes, Karine Braga,Guimar?es, Luciana,Lima, Maria Eduarda Toledo,Mateus, Marcella Fernandes Mano,Nascimento, Clebio Soares
, p. 932 - 938 (2020/12/23)
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.
A complementary approach to 3,5-substituted pyrazoles with tosylhydrazones and terminal alkynes mediated by TfOH
Liu, Ping,Xu, Qian-Qian,Dong, Chao,Lei, Xinsheng,Lin, Guo-Qiang
supporting information, p. 2087 - 2092 (2012/11/07)
A complementary method for the preparation of 3,5-substituted pyrazoles in moderate to high yields has been explored via TfOH-induced addition of tosylhydrazones to the terminal alkynes. This acid-induced addition procedure might be an operationally safe alternative compared to typical 1,3-dipolar cycloaddition as there is no involvement of diazo compounds.
