2014 |
Martinez-Cifuentes, M; Clavijo-Allancan, G; Vaggio-Conejeros, Di C; Weiss-Lopez, B; Araya-Maturana, R On-Water Reactivity and Regioselectivity of Quinones in C-N Coupling with Amines: Experimental and Theoretical Study Artículo de revista Australian Journal of Chemistry, 67 (2), pp. 217-224, 2014, ISSN: 0004-9425. Resumen | Enlaces | BibTeX | Etiquetas: addition, alkaloids conjugate derivatives, electrophilicity, green nucleophilicity, potentials, protocol @article{RN214, title = {On-Water Reactivity and Regioselectivity of Quinones in C-N Coupling with Amines: Experimental and Theoretical Study}, author = { M. Martinez-Cifuentes and G. Clavijo-Allancan and C. Di Vaggio-Conejeros and B. Weiss-Lopez and R. Araya-Maturana}, url = {/brokenurl#<Go to ISI>://WOS:000335560100006}, doi = {10.1071/Ch13355}, issn = {0004-9425}, year = {2014}, date = {2014-01-01}, journal = {Australian Journal of Chemistry}, volume = {67}, number = {2}, pages = {217-224}, abstract = {A study about the oxidative coupling of some representative carbo- and heterocyclic non-symmetrical quinones with aryl- and alkylamines, was carried out comparing dichloromethane and water as reaction mediums. We found that the on-water reactions gave better or, at worst, the same results as a conventional organic medium like dichloromethane. Descriptors derived from conceptual density functional theory and approaches of electrostatic nature, such as the molecular electrostatic potential, were used to explain the observed chemical reactivity and regioselectivity. Further, the on-water conditions were used to obtain 24 new aminoquinones with potential biological activity.}, keywords = {addition, alkaloids conjugate derivatives, electrophilicity, green nucleophilicity, potentials, protocol}, pubstate = {published}, tppubtype = {article} } A study about the oxidative coupling of some representative carbo- and heterocyclic non-symmetrical quinones with aryl- and alkylamines, was carried out comparing dichloromethane and water as reaction mediums. We found that the on-water reactions gave better or, at worst, the same results as a conventional organic medium like dichloromethane. Descriptors derived from conceptual density functional theory and approaches of electrostatic nature, such as the molecular electrostatic potential, were used to explain the observed chemical reactivity and regioselectivity. Further, the on-water conditions were used to obtain 24 new aminoquinones with potential biological activity. |
Cerda-Monje, A; Ormazabal-Toledo, R; Cardenas, C; Fuentealba, P; Contreras, R Regional Electrophilic and Nucleophilic Fukui Functions Efficiently Highlight the Lewis Acidic/Basic Regions in Ionic Liquids Artículo de revista Journal of Physical Chemistry B, 118 (13), pp. 3696-3701, 2014, ISSN: 1520-6106. Resumen | Enlaces | BibTeX | Etiquetas: alkenes, alkynes, aromatic designer diels-alder electrostatic future, knoevenagel, potentials, rationalization reaction, reactivity, solvents, substitutions @article{RN223, title = {Regional Electrophilic and Nucleophilic Fukui Functions Efficiently Highlight the Lewis Acidic/Basic Regions in Ionic Liquids}, author = { A. Cerda-Monje and R. Ormazabal-Toledo and C. Cardenas and P. Fuentealba and R. Contreras}, url = {/brokenurl#<Go to ISI>://WOS:000333948200024}, doi = {10.1021/jp5009994}, issn = {1520-6106}, year = {2014}, date = {2014-01-01}, journal = {Journal of Physical Chemistry B}, volume = {118}, number = {13}, pages = {3696-3701}, abstract = {The origin of catalysis and selectivity induced by room temperature ionic liquids in several organic reactions has putatively been associated with the concept of cation effect (hydrogen bond donor ability of the ionic liquids) or anion effect (hydrogen bond accepting ability of the ionic liquids). We show that there may be cases where this a priori classification may not be correctly assigned. Cations may concentrate both Lewis acidity and basicity functions in one fragment of the ionic liquid: an effect we tentatively call bifunctional distribution of the molecular Lewis acidity/basicity. Bifunctionality on the cation is however anion dependent through electronic polarization effects. The molecular distribution of the Lewis acidity/basicity may simply be assessed by evaluating the regional Fukui function within a reference ion pair structure. The model is tested for a set of nine ionic liquids based on the 1-butyl-3-methylimidazolium cation commonly used as solvent to run organic reactions.}, keywords = {alkenes, alkynes, aromatic designer diels-alder electrostatic future, knoevenagel, potentials, rationalization reaction, reactivity, solvents, substitutions}, pubstate = {published}, tppubtype = {article} } The origin of catalysis and selectivity induced by room temperature ionic liquids in several organic reactions has putatively been associated with the concept of cation effect (hydrogen bond donor ability of the ionic liquids) or anion effect (hydrogen bond accepting ability of the ionic liquids). We show that there may be cases where this a priori classification may not be correctly assigned. Cations may concentrate both Lewis acidity and basicity functions in one fragment of the ionic liquid: an effect we tentatively call bifunctional distribution of the molecular Lewis acidity/basicity. Bifunctionality on the cation is however anion dependent through electronic polarization effects. The molecular distribution of the Lewis acidity/basicity may simply be assessed by evaluating the regional Fukui function within a reference ion pair structure. The model is tested for a set of nine ionic liquids based on the 1-butyl-3-methylimidazolium cation commonly used as solvent to run organic reactions. |
Gallardo-Fuentes, S; Tapia, R A; Contreras, R; Campodonico, P R Site Activation Effects Promoted by Intramolecular Hydrogen Bond Interactions in Snar Reactions Artículo de revista Rsc Advances, 4 (58), pp. 30638-30643, 2014, ISSN: 2046-2069. Resumen | Enlaces | BibTeX | Etiquetas: aromatic electrophilicity, functionals, markovnikov model molecules, nucleophilic-substitution, potentials, reactivity, regioselectivity rule, secondary-amines, solvent @article{RN225, title = {Site Activation Effects Promoted by Intramolecular Hydrogen Bond Interactions in Snar Reactions}, author = { S. Gallardo-Fuentes and R.A. Tapia and R. Contreras and P.R. Campodonico}, url = {/brokenurl#<Go to ISI>://WOS:000340500300025}, doi = {10.1039/c4ra04725g}, issn = {2046-2069}, year = {2014}, date = {2014-01-01}, journal = {Rsc Advances}, volume = {4}, number = {58}, pages = {30638-30643}, abstract = {The nucleophilic aromatic substitution reaction of benzohydrazide derivatives towards 2-chloro-5nitropyrimidine is used as model system to experimentally and theoretically show that intramolecular hydrogen-bond formation operates as a perturbation that elicits a dual response at the reaction center of the transition state (TS) structure, by enhancing the electrophilicity of the pyrimidine moiety and the nucleophilicity of the nitrogen atom of the benzohydrazide fragment. The electronic mechanism can therefore be described as a (non-local) site activation problem.}, keywords = {aromatic electrophilicity, functionals, markovnikov model molecules, nucleophilic-substitution, potentials, reactivity, regioselectivity rule, secondary-amines, solvent}, pubstate = {published}, tppubtype = {article} } The nucleophilic aromatic substitution reaction of benzohydrazide derivatives towards 2-chloro-5nitropyrimidine is used as model system to experimentally and theoretically show that intramolecular hydrogen-bond formation operates as a perturbation that elicits a dual response at the reaction center of the transition state (TS) structure, by enhancing the electrophilicity of the pyrimidine moiety and the nucleophilicity of the nitrogen atom of the benzohydrazide fragment. The electronic mechanism can therefore be described as a (non-local) site activation problem. |
2014 |
On-Water Reactivity and Regioselectivity of Quinones in C-N Coupling with Amines: Experimental and Theoretical Study Artículo de revista Australian Journal of Chemistry, 67 (2), pp. 217-224, 2014, ISSN: 0004-9425. |
Regional Electrophilic and Nucleophilic Fukui Functions Efficiently Highlight the Lewis Acidic/Basic Regions in Ionic Liquids Artículo de revista Journal of Physical Chemistry B, 118 (13), pp. 3696-3701, 2014, ISSN: 1520-6106. |
Site Activation Effects Promoted by Intramolecular Hydrogen Bond Interactions in Snar Reactions Artículo de revista Rsc Advances, 4 (58), pp. 30638-30643, 2014, ISSN: 2046-2069. |