2017 |
Almodovar, I; Rezende, M C; Cassels, B K; Garcia-Arriagada, M Theoretical Insights into the Regioselectivity of a Pictet-Spengler Reaction: Transition State Structures Leading to Salsolinol and Isosalsolinol Artículo de revista Journal of Physical Organic Chemistry, 30 (8), 2017, ISSN: 0894-3230. Resumen | Enlaces | BibTeX | Etiquetas: borylation, calculations, catalyzed condensation, density-functional-approach, derivatives dft dopamine, frontier-electron isosalsolinol, mechanism, norcoclaurine of pictet-spengler regioselectivity, salsolinol, synthase, tautomerism, theory @article{RN343, title = {Theoretical Insights into the Regioselectivity of a Pictet-Spengler Reaction: Transition State Structures Leading to Salsolinol and Isosalsolinol}, author = { I. Almodovar and M.C. Rezende and B.K. Cassels and M. Garcia-Arriagada}, url = {/brokenurl#<Go to ISI>://WOS:000406979900005}, doi = {10.1002/poc.3666}, issn = {0894-3230}, year = {2017}, date = {2017-01-01}, journal = {Journal of Physical Organic Chemistry}, volume = {30}, number = {8}, abstract = {The mechanism of the cyclization step of the Pictet-Spengler reaction between acetaldehyde and dopamine to give salsolinol and isosalsolinol was studied computationally, using density functional theory. The preferential formation in acidic media of salsolinol, the product of para-cyclization, and the requirement of a neutral pH for the formation of the ortho-cyclized isosalsolinol are explained in terms of 2 different mechanistic routes with an iminium ion or a phenolate-iminium zwitterion as starting reactants.}, keywords = {borylation, calculations, catalyzed condensation, density-functional-approach, derivatives dft dopamine, frontier-electron isosalsolinol, mechanism, norcoclaurine of pictet-spengler regioselectivity, salsolinol, synthase, tautomerism, theory}, pubstate = {published}, tppubtype = {article} } The mechanism of the cyclization step of the Pictet-Spengler reaction between acetaldehyde and dopamine to give salsolinol and isosalsolinol was studied computationally, using density functional theory. The preferential formation in acidic media of salsolinol, the product of para-cyclization, and the requirement of a neutral pH for the formation of the ortho-cyclized isosalsolinol are explained in terms of 2 different mechanistic routes with an iminium ion or a phenolate-iminium zwitterion as starting reactants. |
2014 |
Aliaga, M E; Tiznado, W; Cassels, B K; Nunez, M; Millan, D; Perez, E G; Garcia-Beltran, O; Pavez, P Substituent Effects on Reactivity of 3-Cinnamoylcoumarins with Thiols of Biological Interest Artículo de revista Rsc Advances, 4 (2), pp. 697-704, 2014, ISSN: 2046-2069. Resumen | Enlaces | BibTeX | Etiquetas: alpha, beta-unsaturated chemical-reactivity, cysteine, density-functional-approach, disease, electrophilicity fluorescent, glutathione, ketones, michael probe, turn-on @article{RN195, title = {Substituent Effects on Reactivity of 3-Cinnamoylcoumarins with Thiols of Biological Interest}, author = { M.E. Aliaga and W. Tiznado and B.K. Cassels and M. Nunez and D. Millan and E.G. Perez and O. Garcia-Beltran and P. Pavez}, url = {/brokenurl#<Go to ISI>://WOS:000327849700027}, doi = {10.1039/c3ra44695f}, issn = {2046-2069}, year = {2014}, date = {2014-01-01}, journal = {Rsc Advances}, volume = {4}, number = {2}, pages = {697-704}, abstract = {The Michael addition reactions of the biothiols cysteine, homocysteine, cysteinyl-glycine, gamma-glutamylcysteine and glutathione with 3-cinnamoylcoumarin derivatives (ChC1-ChC4) in aqueous solution (30 degrees C, ionic strength 0.2 M KCI) were followed fluorimetrically and evaluated kinetically. The study was completed with a theoretical analysis based on the inverse of the Fukui potential (1/v(f) (r)), which is proposed for the first time as a local softness descriptor. Thus, considering both experimental results and theoretical analysis, the following conclusions can be drawn: (i) the reactivity of the tested probes towards Michael addition increases in the para-substitution sequence: H < OEt < SMe < Br < NO2, and is not correlated with the sigma(P) values of the substituents; (ii) in turn, the descriptor proposed here as local softness (1/v(f) (r)) appears as a promising reactivity index that is able to explain the higher k(N) values found for both electron-withdrawing and electron-donating groups; (iii) the nucleophilic reactivity of the biothiols employed increases in the sequence Cys-Gly < Hcy < GSH < Cys < gamma-Glu-Cys; and also finally (iv) we have demonstrated that these probes can be used for fluorimetric thiol determination in SH-SY5Y cells.}, keywords = {alpha, beta-unsaturated chemical-reactivity, cysteine, density-functional-approach, disease, electrophilicity fluorescent, glutathione, ketones, michael probe, turn-on}, pubstate = {published}, tppubtype = {article} } The Michael addition reactions of the biothiols cysteine, homocysteine, cysteinyl-glycine, gamma-glutamylcysteine and glutathione with 3-cinnamoylcoumarin derivatives (ChC1-ChC4) in aqueous solution (30 degrees C, ionic strength 0.2 M KCI) were followed fluorimetrically and evaluated kinetically. The study was completed with a theoretical analysis based on the inverse of the Fukui potential (1/v(f) (r)), which is proposed for the first time as a local softness descriptor. Thus, considering both experimental results and theoretical analysis, the following conclusions can be drawn: (i) the reactivity of the tested probes towards Michael addition increases in the para-substitution sequence: H < OEt < SMe < Br < NO2, and is not correlated with the sigma(P) values of the substituents; (ii) in turn, the descriptor proposed here as local softness (1/v(f) (r)) appears as a promising reactivity index that is able to explain the higher k(N) values found for both electron-withdrawing and electron-donating groups; (iii) the nucleophilic reactivity of the biothiols employed increases in the sequence Cys-Gly < Hcy < GSH < Cys < gamma-Glu-Cys; and also finally (iv) we have demonstrated that these probes can be used for fluorimetric thiol determination in SH-SY5Y cells. |
2017 |
Theoretical Insights into the Regioselectivity of a Pictet-Spengler Reaction: Transition State Structures Leading to Salsolinol and Isosalsolinol Artículo de revista Journal of Physical Organic Chemistry, 30 (8), 2017, ISSN: 0894-3230. |
2014 |
Substituent Effects on Reactivity of 3-Cinnamoylcoumarins with Thiols of Biological Interest Artículo de revista Rsc Advances, 4 (2), pp. 697-704, 2014, ISSN: 2046-2069. |