Showing papers by "Juan A. Squella published in 2010"
TL;DR: In this article, one-pot synthesizations for substituted chromeno, dihydropyridines, and pyridine rings have been proposed to further study their biological activity.
Abstract: Substituted chromenos, dihydropyridines and pyridines have been important in the syntheses of compounds having interesting pharmacological properties. Therefore, we found of interest to synthesize chromenopyridines and chromenodihydropyridines (i.e., fused chromeno and dihydropyridine or pyridine rings) to further study their biological activity. Here, we propose one-pot syntheses for substituted ethyl-2,4-dimethyl-5-oxo-5H-chromeno[4,3-b]pyridine-3-carboxylates, ethyl-2,4-dimethyl-5-oxo-5H-chromeno[3,4-c]pyridine-3-carboxylates and their respective 1,4-dihydropyridines based on a modified Hantzsch pyridine synthesis using 2-hydroxyaryl aldehydes, with electron withdrawing and electron donating groups on the phenyl ring, as starting reactants. Sixteen compounds were synthesized by the described method and fully characterized. An average yield of 37% was obtained for the different derivatives.
17 citations
TL;DR: In this article, the thermodynamics and kinetics of the adsorption of a redox couple having quinone nature on glassy carbon electrodes were studied by both cyclic (CV) and square wave (SWV) voltammetric techniques.
15 citations
TL;DR: In this paper, C4-phenolic-1, 4-dihydropyridines were used for the characterization of title compounds on glassy carbon electrode (GCE) and reactivity with superoxide radical anion.
12 citations
TL;DR: In this article, the voltammetric reduction of 1-methyl- and 1-H- 4-nitroimidazole derivatives was studied in different protic and aprotic media to investigate the influence of the N-1 substitution in the mechanism of reduction, the susceptibility of the nitro group to reduction, and the stability of the Nitro radical anion.
7 citations
TL;DR: In this article, the electrochemistry of 2,2-dimethyl-(3H)-3-(N-3'-nitrophenylamino)naphtho[1, 2- b]furan-4,5-dione ([Q]-PhNO2), on mercury was investigated.
Abstract: The electrochemistry of 2,2-dimethyl-(3H)-3-(N-3'-nitrophenylamino)naphtho[1,2- b]furan-4,5-dione ([Q]-PhNO2), on mercury was investigated. The first peak is consistent with a quasi-reversible one-electron reduction of the ortho-quinone, forming [Q•-]-PhNO2, while the second one, bielectronic, corresponds to the simultaneous reduction of the latter radical to a dianion and the nitro group to a nitro radical anion. The second order rate constant, kdisp, for the decay of [Q•-]-PhNO2 is 15.188 x 103 ± 827 mol"1 L s"1 and the t1/2 equals 0.06 s. E17Ic values for [Q]-PhNO2 and its precursor, nor-β-lapachone, are similar. The ease of semiquinone generation and its stability are parameters statistically relevant in the correlation biochemical/theoretical aspects.
5 citations