3316-09-4Relevant articles and documents
SYNTHESIS AND SOLVATOCHROMIC AND ACID-BASE REACTIONS OF A BETAINE AND SALTS OF 4-N-PYRIDINIUMCATECHOL
Neiland, O. Ya.,Kraupsha, I. L.,Gudele, I. Ya.
, p. 1428 - 1434 (1993)
Oxidation of catechol by phenyliodosyldiacetate in the presence of pyridine gives 4-N-pyridiniumcatechol salts whose structures are confirmed by an independent synthesis from 2,2-dimethyl-5-aminobenzodioxole.The spectroscopically determined ionization constants for the 4-N-pyridiniumcatechol cation depend on the nature of the buffer cation solution (sodium, ammonium, tetraethylammonium).The large solvatochromic shift in the long wavelength absorption band of the betaine of 4-N-pyridinium-catechol followed the empirical scale of solvent polarity ENT.Introduction of the N-pyridinium group in position 4 increases the acidity of the catechol by 2.7 pK units, which is an almost identical effect to the introduction of a 4-nitro group.However, the solvatochromism for the anion of 4-nitrocatechol is insignificant.The compounds were characterized by their 1H NMR and IR spectra.
-
Swan,Wright
, p. 1549,1554 (1956)
-
Marshall,Wilkinson
, p. 425,431 (1972)
A high yield photochemical preparation of 4 nitrocatechol UL 14C
Norris,Still
, p. 661 - 666 (1973)
-
Enhanced electrochemical degradation of 4-Nitrophenol molecules using novel Ti/TiO2-NiO electrodes
Fadillah, Ganjar,Saleh, Tawfik A.,Wahyuningsih, Sayekti
, (2019)
Removal of 4-Nitrophenol (4-NP) compounds by the electrochemical degradation method using Ti/TiO2-NiO electrodes was successfully conducted. This study aims to study the activity of Ti/TiO2-NiO electrodes in the electrocatalytic degradation of 4-NP as organic compound pollutants. Ti/TiO2-NiO preparation was carried out by the wet impregnation technique, then TiO2-NiO composites were sprayed on the surface of Titanium electrodes. The electrode was characterized by X-Ray Diffraction (XRD), a Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and Cyclic Voltammetry (CV). A Diffractogram XRD of TiO2-NiO composites showed a characteristic peak of TiO2-NiO at 2θ = 33°. Meanwhile, analysis of the SEM surface morphology showed that NiO with an average particle size of 22.07 μm can be attached to the surface of the Ti/TiO2 plate. Electrocatalytic degradation of 4-NP compounds was found to be optimum at pH 11 and 80 min electrolysis time with a rate constant of 0.0373 min?1. The electrochemical degradation exhibited the percentage of removing 4-NP rate of >95% with good electrode measurement stability.
Gas-phase IR cross-sections and single crystal structures data for atmospheric relevant nitrocatechols
Arsene, Cecilia,Bejan, Iustinian-Gabriel,Olariu, Romeo-Iulian,Roman, Claudiu,Roman, Tiberiu
, (2021/09/28)
The gas-phase IR absorption cross sections for 3-nitrocatechol, 5-methyl-3-nitrocatechol, 4-nitrocatechol and 4-methyl-5-nitrocatechol were evaluated using the ESC-Q-UAIC (the environmental simulation chamber made of quartz from the “Alexandru Ioan Cuza” University of Iasi, Romania) photoreactor facilities. Specific infrared absorptions and integrated band intensities in the range of 650–4000 cm?1 were investigated by long path gas-phase FT-IR technique. Two different addition methods (solid and liquid transfer methods) of nitrocatechols into the reactor were employed in these investigations. All investigated nitrocatechols were synthesized and characterized by X-ray diffraction spectroscopy techniques beside traditional nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy in order to evaluate their structure-properties relationship in gas and solid phase. This study reports for the first time the gas-phase infrared cross sections and the X-ray diffraction analysis for (methyl) nitrocatechols.
Regioselective chemoenzymatic syntheses of ferulate conjugates as chromogenic substrates for feruloyl esterases
Gherbovet, Olga,Ferreira, Fernando,Clément, Apolline,Ragon, Mélanie,Durand, Julien,Bozonnet, Sophie,O'Donohue, Michael J.,Fauré, Régis
, p. 325 - 333 (2021/03/15)
Generally, carbohydrate-active enzymes are studied using chromogenic substrates that provide quick and easy color-based detection of enzyme-mediated hydrolysis. For feruloyl esterases, commercially available chromogenic ferulate derivatives are both costly and limited in terms of their experimental application. In this study, we describe solutions for these two issues, using a chemoenzymatic approach to synthesize different ferulate compounds. The overall synthetic routes towards commercially available 5-bromo-4-chloro-3-indolyl and 4-nitrophenyl 5-O-feruloyl-α-l-arabinofuranosides were significantly shortened (from 7 or 8 to 4-6 steps), and the transesterification yields were enhanced (from 46 to 73% and from 47 to 86%, respectively). This was achieved using enzymatic (immobilized Lipozyme TL IM from Thermomyces lanuginosus) transesterification of unprotected vinyl ferulate to the primary hydroxy group of α‐l‐arabinofuranosides. Moreover, a novel feruloylated 4-nitrocatechol-1-yl-substituted butanetriol analog, containing a cleavable hydroxylated linker, was also synthesized in 32% overall yield in 3 steps (convergent synthesis). The latter route combined the regioselective functionalization of 4-nitrocatechol and enzymatic transferuloylation. The use of this strategy to characterize type A feruloyl esterase from Aspergillus Niger reveals the advantages of this substrate for the characterizations of feruloyl esterases.
Dearomatization of Electron-Deficient Phenols to ortho-Quinones: Bidentate Nitrogen-Ligated Iodine(V) Reagents
Xiao, Xiao,Greenwood, Nathaniel S.,Wengryniuk, Sarah E.
, p. 16181 - 16187 (2019/11/05)
Despite their broad utility, the synthesis of ortho-quinones remains a significant challenge, in particular, access to electron-deficient derivatives remains an unsolved problem. Reported here is the first general method for the synthesis of electron-deficient ortho-quinones by direct oxidation of phenols. The reaction is enabled by a novel bidentate nitrogen-ligated iodine(V) reagent, a previously unexplored class of compounds which we have termed Bi(N)-HVIs. The reaction is extremely general and proceeds with excellent regioselectivity for the ortho over para isomer. Functionalization of the ortho-quinone products was examined, resulting in a facile one-pot synthesis of catechols, as well as the incorporation of a variety of heteroatom nucleophiles. This method represents the first synthetic application of Bi(N)-HVIs and demonstrates their potential as a platform for the further development of highly reactive, but also highly tunable, I(V) reagents.
