The oxidation of three synthesized 7-, 8- and 9-hydroxycoumarin[4,3-b]pyridines isomers on glassy carbon electrode (GCE) in dimethylformamide is reported. Voltammetry, chronoamperometry, UV-Visible spectroscopy and spectroelectrochemistry were employed to collect data that permitted us to establish the oxidation behavior of hydroxy-substituted pyridine-fused coumarins. The oxidation of the phenol moiety is irreversible in character and the overall oxidation process involves 2-electrons and 2-protons, to give the corresponding quinone-type derivatives. Furthermore, cyclic voltammetry supports the conclusion of that the oxidation of the 9-hydroxy-substituted derivative occurs in two steps in an ECE mechanism. Chronoamperometry permits us to determine the number of electrons for each step, thus supporting the mentioned ECE mechanism. Additionally, the effect of tetrabutylammonium hydroxide on the oxidation of the compounds was studied through UV-Visible spectroscopy and voltammetry. Spectroelectrochemical data showed that the quinone products of the electrolysis absorb in the range of 337-381 nm. Comparative studies by cyclic voltammetry revealed that hydroxy-substituted coumarin[4,3-b]pyridines are oxidized more easily than 3-acetyl-8-hydroxycoumarin and phenol. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3615933] All rights reserved.
The oxidation of three synthesized 7-, 8- and 9-hydroxycoumarin[4,3-b]pyridines isomers on glassy carbon electrode (GCE) in dimethylformamide is reported. Voltammetry, chronoamperometry, UV-Visible spectroscopy and spectroelectrochemistry were employed to collect data that permitted us to establish the oxidation behavior of hydroxy-substituted pyridine-fused coumarins. The oxidation of the phenol moiety is irreversible in character and the overall oxidation process involves 2-electrons and 2-protons, to give the corresponding quinone-type derivatives. Furthermore, cyclic voltammetry supports the conclusion of that the oxidation of the 9-hydroxy-substituted derivative occurs in two steps in an ECE mechanism. Chronoamperometry permits us to determine the number of electrons for each step, thus supporting the mentioned ECE mechanism. Additionally, the effect of tetrabutylammonium hydroxide on the oxidation of the compounds was studied through UV-Visible spectroscopy and voltammetry. Spectroelectrochemical data showed that the quinone products of the electrolysis absorb in the range of 337-381 nm. Comparative studies by cyclic voltammetry revealed that hydroxy-substituted coumarin[4,3-b]pyridines are oxidized more easily than 3-acetyl-8-hydroxycoumarin and phenol. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3615933] All rights reserved.
Design, synthesis and antifungal activity evaluation of chromeno[4,3-b]pyridin-5-one derivatives
作者:Jinmeng Yu、Ming Gao、Rongmei Zhao、Haifeng Liu、Hailing Fan、Le Pan、Lu Jin
DOI:10.1016/j.phytol.2023.07.009
日期:2023.10
excellent inhibitory activity. The structure-activity relationship suggested that the length of the four carbon atoms in the side chain had significant effects on the antifungalactivity. Our results revealed that a new series of chromeno[4,3-b]pyridin-5-one showed potential as an effective antifungal scaffold, and also provided a possibility for the structure design optimization, synthesis and development
基于天然产物(polynemoraline C)中发现的色烯基[4,3- b ]吡啶-5-酮支架,设计并研究了一系列45种新型衍生物的杀菌活性和相应的合成方法。所有化合物均通过1 H NMR 和13 C NMR进行表征,部分化合物通过 HR-MS 进行表征。筛选了 100 µg/mL 浓度下对链格孢、茄链格孢、灰葡萄孢、尖孢镰刀菌的抗真菌活性。结果表明,大多数化合物对Alternaria alternata和Alternaria solani的作用比对Botrytis cinerea更有效。和尖镰孢。一些化合物优于阳性对照。在合成的衍生物中,化合物1b对Alternaria alternata和Alternaria solani表现出显着的活性。化合物1b在100 µg/mL浓度下对链格孢菌的抑制率达到62.09 %,高于阳性对照百菌清(38.81 %)和嘧菌酯(50.06 %),而对茄斑病菌的抑制率为54
On the one pot syntheses of chromeno[4,3-b]pyridine-3-carboxylate and chromeno[3,4-c]pyridine-3-carboxylate and dihydropyridines
作者:Patricio A. Navarrete-Encina、Ricardo Salazar、Christian Vega-Retter、Karina Pérez、Juan A. Squella、Luis J. Nuñez-Vergara
DOI:10.1590/s0103-50532010000300003
日期:——
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.
Electrochemical Oxidation of 7-, 8- and 9-Hydroxy-3-ethoxycarbonyl-2,4-dimethyl coumarin[4,3-b]Pyridine Isomers at Glassy Carbon in Dimethylformamide
作者:V. Pardo-Jiménez、C. Barrientos、J. A. Squella、P. A. Navarrete-Encina、Luis J. Nuñez-Vergara
DOI:10.1149/1.3615933
日期:——
The oxidation of three synthesized 7-, 8- and 9-hydroxycoumarin[4,3-b]pyridines isomers on glassy carbon electrode (GCE) in dimethylformamide is reported. Voltammetry, chronoamperometry, UV-Visible spectroscopy and spectroelectrochemistry were employed to collect data that permitted us to establish the oxidation behavior of hydroxy-substituted pyridine-fused coumarins. The oxidation of the phenol moiety is irreversible in character and the overall oxidation process involves 2-electrons and 2-protons, to give the corresponding quinone-type derivatives. Furthermore, cyclic voltammetry supports the conclusion of that the oxidation of the 9-hydroxy-substituted derivative occurs in two steps in an ECE mechanism. Chronoamperometry permits us to determine the number of electrons for each step, thus supporting the mentioned ECE mechanism. Additionally, the effect of tetrabutylammonium hydroxide on the oxidation of the compounds was studied through UV-Visible spectroscopy and voltammetry. Spectroelectrochemical data showed that the quinone products of the electrolysis absorb in the range of 337-381 nm. Comparative studies by cyclic voltammetry revealed that hydroxy-substituted coumarin[4,3-b]pyridines are oxidized more easily than 3-acetyl-8-hydroxycoumarin and phenol. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3615933] All rights reserved.