Browsing by Author "Tapia, Ricardo A."
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Item Activation of Electrophile/Nucleophile Pair by a Nucleophilic and Electrophilic Solvation in a SNAr Reaction(2018) Sánchez, Bruno; Calderon, Cristian; Tapia, Ricardo A.; Contreras, Renato; Campodónico, PaolaNucleophilic aromatic substitution reactions of 4-chloroquinazoline toward aniline and hydrazine were used as a model system to experimentally show that a substrate bearing heteroatoms on the aromatic ring as substituent is able to establish intramolecular hydrogen bond which may be activated by the reaction media and/or the nature of the nucleophile.Item Effect of the nature of the nucleophile and solvent on an SNAr reaction(2018) Gazitúa, Marcela; Tapia, Ricardo A.; Contreras, Renato; Campodónico, PaolaThe reaction of 2,4-dinitrobenzenesulfonyl chloride toward propylamine was kinetically evaluated in 19 organic solvents and 10 ionic liquids as reaction media. This study was compared with a previous study to experimentally show that solvent effects and the nature of the reacting pair drastically affect the reaction rate and the reaction mechanism. While the reaction of the reference electrophile 2,4-dinitrobenzenesulfonyl chloride with piperidine is favored in polar solvents with the ability to donate or accept hydrogen bonds, the reaction with propylamine is favored in solvents with the ability to accept hydrogen bonds.Item Experimental Analyses Emphasize the Stability of the Meisenheimer Complex in a S N Ar Reaction Toward Trends in Reaction Pathways(2020-07) Campodónico, Paola; Olivares, Belén; Tapia, Ricardo A.The mechanism of SNAr reactions between 2-chloro-5-nitropyrimidine with primary and secondary alicyclic amines, respectively, have been studied by kinetic measurements. The kinetic data obtained in aqueous media opens a controversial discussion based on Brönsted-type plots analysis. The first approach based on the kinetic data reveals a non-catalyzed pathway. Then, the subtlety of the mathematical treatment of the kinetic data is discussed over a concerted or stepwise mechanism, respectively.