54-06-8Relevant academic research and scientific papers
Activation of H2O2 and superoxide production using a novel cobalt complex based on a polyampholyte
Lombardo Lupano, Lucía V.,Lázaro Martínez, Juan Manuel,Piehl, Lidia Leonor,Rubin De Celis, Emilio,Campo Dall'Orto, Viviana
, p. 342 - 354 (2013)
A new catalyst based on Co(II) and a hydrogel with property of polyampholyte was characterized by equilibrium studies of Co(II) uptake, solid-state NMR and energy dispersive X-ray analysis. The matrix derived from methacrylic acid and 2-methylimidazole is easily synthesized in one-spot strategy, and combines coordination properties with chemical resistance. The catalytic activity of this material on H2O2 activation was studied by electron spin resonance, which confirmed the release of superoxide radical. A possible mechanism of interaction involves the simultaneous production of dioxygen, protons and water. The catalytic performance was assessed in the activation of H2O2 for the oxidation of two representative organic compounds of environmental concern. About 70% of methyl orange, a model azo dye, was removed from distilled water in 2 h by oxidation with H2O2 60 mM and by adsorption on the catalyst. The amount of adsorbed dye was minimized in the presence of 0.1 M Na2SO4. The kinetics of the processes followed a pseudo-first-order empirical model, and the catalyst was recovered and re-used. Epinephrine was chosen as a pharmaceutical model susceptible to superoxide attack. About 80% of conversion to adrenochrome was reached in less than 6 min, following a pseudo-first-order kinetic model.
Utilization of a new gold/Schiff-base iron(iii) complex composite as a highly sensitive voltammetric sensor for determination of epinephrine in the presence of ascorbic acid
Gorczyński, Adam,Kubicki, Maciej,Szymkowiak, Klaudia,?uczak, Teresa,Patroniak, Violetta
, p. 101888 - 101899 (2016)
The preparation of new materials that can act as systems capable of sensing biologically relevant molecules constitutes a significant modern challenge as well as a necessity oriented towards disease prevention. Subcomponent self-assembly of 2-(methylhydrazino)benzimidazole, 4-tert-butyl-2,6-diformylphenol and Fe(ClO4)2(H2O)6 leads to a new, bimetallic iron(iii) complex of the following formula: [Fe2(H3L)2(MeOH)2(μ-OMe)2](ClO4)4 (1), as established by ESI-MS, FTIR and single crystal X-ray analysis. It is important to note that ligand H3L was also successfully synthesized and characterized for the first time. Compound 1 was successfully deposited on a gold electrode and applied as a voltammetric sensor with respect to epinephrine (EP). Cyclic voltammograms (CVs) proved the catalytic activity of the new, electrochemically prepared composite Au/1 for the oxidation of EP in the presence of ascorbic acid (AA). The respective current peaks were clearly separated from each other, thus enabling selective detection of these compounds coexisting in a mixture. For the prepared sensor a linear relationship between the current response of EP electrooxidation at the potential of peak maximum (ip) and the concentration of EP in solution (cEP) in the presence of constant AA concentration was found in the broad range of cEP (R2 ≥ 0.9997, 1.0 × 10?8 M to 9.0 × 10?4 M) with a high detection limit (7.4 × 10?9 M), excellent reproducibility as well as high stability.
Kinetic studies on the manganese(II) complex catalyzed oxidation of epinephrine
Szigyártó, I.Cs.,Szabó,Simándi
, p. 66 - 71 (2013)
The manganese complex [Mn2(HL)2](BPh 4)2 was found to be a selective catalyst for the oxidation of epinephrine (a catecholamine derivative) to adrenochrome at room temperature in sodium carbonate-bicarbonate buffer. The epinephrine auto-oxidation rate significantly increases upon the addition of manganese complex. The kinetics of reaction was studied by spectrophotometric method, monitoring the increase in concentration of adrenochrome product. According to the proposed mechanism, O2 binding to the manganese complex is followed by the formation of a ternary catalyst-dioxygen-substrate complex as active intermediate, which decomposes in a rate-determining step, generating the adrenochrome.
Renalase does not catalyze the oxidation of catecholamines
Beaupre, Brett A.,Hoag, Matthew R.,Moran, Graham R.
, p. 62 - 66 (2015)
Abstract It is widely accepted that the function of human renalase is to oxidize catecholamines in blood. However, this belief is based on experiments that did not account for slow, facile catecholamine autoxidation reactions. Recent evidence has shown that renalase has substrates with which it reacts rapidly. The reaction catalyzed defines renalase as an oxidase, one that harvests two electrons from either 2-dihydroNAD(P) or 6-dihydroNAD(P) to form β-NAD(P)+ and hydrogen peroxide. The apparent metabolic purpose of such a reaction is to avoid inhibition of primary dehydrogenase enzymes by these β-NAD(P)H isomers. This article demonstrates that renalase does not catalyze the oxidation of neurotransmitter catecholamines. Using high-performance liquid chromatography we show that there is no evidence of consumption of epinephrine by renalase. Using time-dependent spectrophotometry we show that the renalase FAD cofactor spectrum is unresponsive to added catecholamines, that adrenochromes are not observed to accumulate in the presence of renalase and that the kinetics of single turnover reactions with 6-dihydroNAD are unaltered by the addition of catecholamines. Lastly we show using an oxygen electrode assay that plasma renalase activity is below the level of detection and only when exogenous renalase and 6-dihydroNAD are added can dioxygen be observed to be consumed.
The Oxovanadyl(IV) catalysed Oxidation of Adrenaline by Molecular Oxygen
Jameson, Reginald F.,Kiss, Tamas
, p. 1833 - 1838 (1986)
The oxidation of adrenaline (H2LH+) by molecular oxygen in the presence of catalytic amounts of VO2+ ions has been followed using a Clark-type oxygen electrode.The empirical rate law -d/dt = kobs. + p was obtained in which p is a small constant (only observable at low pH) and kobs. is given by the relationship (i), where T and T are total initial concentrations of (i) VO2+ and adrenaline respectively.It is demonstrated that this behaviour is consistent with the involvement of both VO2+ and V2+ species and furthermore that it also calls for the presence of a tris(adrenaline) species, V(LH)3+.A kinetically determined equilibrium constant for reaction (ii) is VO(LH)2 + H2LH+ V(LH)3+ + H2O (ii) reported.The necessary proton- and metal-ligand equilibrium constants were obtained by pH- and 1H n.m.r.-titration techniques.All solutions were made up to a constant ionic strength (I = 0.100 mol dm-3) with KNO3 at 25.00 +/- 0.02 deg C.
Kinetics of the autoxidation of adrenaline and [copper(II)(adrenaline)] 2+ in alkaline aqueous and micellar media
Al-Ayed, Abdullah S.,Al-Lohedan, Hamad A.,Rafiquee,Ali, Mohd Sajid,Issa, Zuheir A.
, p. 173 - 181 (2013)
The kinetics of autoxidation of adrenaline and [Cu(adrenaline)] 2+ complex by dissolved oxygen in alkaline aqueous and micellar media has been studied. The reaction is initiated by the removal of amino-H + protons of adrenaline by hydroxide ion, followed by cyclization. The values of (1/k obs) for the autoxidation of both species were found to be linearly dependent upon 1/[OH-]. The reaction follows a consecutive pathway in which the intermediate adrenochrome remains stable for few minutes, and then undergoes further reactions to yield adrenolutin and other products. The [Cu(adrenochrome)]+ complex is stable for a few hours. Studies on the effects of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) on the reactivity of both species revealed different behaviors. The micelles of CTAB catalyzed the rates of autoxidation for both species, whereas SDS micelles inhibited the autoxidation of adrenaline but catalyzed the rate of autoxidation of [Cu(adrenaline)]2+. Addition of the reactive counterion surfactant, cetyltrimethylammonium hydroxide (CTAOH) initially increased the rate constant with the increasing [CTAOH], until it reached a plateau for k ψ -[CTAOH]. Salts such as NaCl, NaBr, tetramethyl ammonium bromide, and tetraethyl ammonium bromide increased the rate when added at lower concentrations, but had negligible effect at higher concentrations. The results obtained in micellar media were treated according to Berezin's Pseudophase Model. The various kinetic parameters for the reactions occurring in aqueous and in micellar media are reported.
Production process of adrenal glands
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Paragraph 0035-0036, (2021/11/15)
The invention discloses a production technology for carbazochrome. The production technology comprises the following steps: 1) synthesizing chloracetyl catechol; 2) synthesizing corticosterone hydrochloride; 3) synthesizing adrenaline; and 4) synthesizing the carbazochrome. The production technology for the carbazochrome, disclosed by the invention, has the advantages of simple preparation method,few steps and easiness for operation and control; and an obtained product has good color and luster, good quality, high purity and high yield, can be directly used for production and utilization andhas very good practicability.
Catecholamine-induced release of nitric oxide from N-nitrosotryptophan derivatives: A non-enzymatic method for catecholamine oxidation
Kytzia, Anna,Korth, Hans-Gert,De Groot, Herbert,Kirsch, Michael
, p. 257 - 267 (2007/10/03)
In recent years, interest in the physiological functions of S-nitrosothiols has strongly increased owing to the potential of these compounds to release nitric oxide. In contrast, little is known about similar functions of N-nitrosated (N-terminal-blocked) tryptophan derivatives, which can be also formed at physiological pH. Utilizing N-acetyl-N-nitrosotryptophan (NANT) and N-nitrosomelatonin (NOMela) as model compounds, we have studied their reaction with catechol and catecholamines such as epinephrine and dopamine. In these reactions, NANT was quantitatively converted to N-acetyltryptophan (NAT), and nitric oxide was identified as a volatile product. During this process, ortho-semiquinone-type radical anions deriving from catechol and dopamine, were detected by ESR spectrometry. The catechol radical concentration was about eight times higher under normoxia than under hypoxia and a similar relationship was found for the decay rates of NANT under these conditions. An epinephrine-derived oxidation product, namely adrenochrome, but not a catechol-derived one, was identified. These observations strongly indicate that N-nitrosotryptophan derivatives transfer their nitroso-function to an oxygen atom of the catecholamines, and that the so-formed intermediary aryl nitrite may decompose homolytically with release of nitric oxide, in addition to a competing hydrolysis reaction to yield nitrite and the corresponding catechol. These conclusions were supported by quantum chemical calculations performed at the CBS-QB3 level of theory. Since nitric oxide is non-enzymatically released from N-nitrosotryptophan derivatives on reaction with catecholamines, there might be a possibility for the development of epinephrine-antagonizing drugs in illnesses like hypertension and pheochromocytoma. The Royal Society of Chemistry 2006.
Disproportionation during electrooxidation of catecholamines at carbon-fiber microelectrodes
Clolkowski, Edward L.,Maness, Karolyn M.,Cahill, Paula S.,Mark Wlghtman,Evans, Dennls H.,Fossel, Bruno,Amatore, Christian
, p. 3611 - 3617 (2007/10/02)
The effect of following chemical reactions during chrono-amperometry and cyclic foltammetry at microelectrodes has been evaluated by digital simulation and the results have been compared to experiments. This study was motivated by the emonstrated utility of microelectrodes to monitor catecholamine secretion from individual biological cells. Since following chemical reactions can increase the total number of coulombs passed, such an occurrence can affect the calibration of the measured response. However, at microelectroies, products formed by chemical reactions after electron transfer are less likely to return to the electrode because of the divergent diffusion field that can exist at electrodes of small dimensions. The degree to which these effects are apparent has been evaluated quantitatively by digital simulation of the DISP1 scheme for a disk-shaped electrode. The predictions of the simulation are verified in an experimental study of the anodic oxidation of diphenylanthracene in acetonitrile containing pyridine. In contrast, the DISP1 reaction of catecholamines at carbon-fiber microelectrodes exhibits much less enhanced current than predicted by theory. The experimental data suggest this is due to the heterogenous nature of the carbon surface with respect to electron transfer. Thus, for most applications of carbonfiber microelectrodes as sensors of catecholamine secretion from cells, the effect of the DISP1 reaction can be ignored.
The participation of Singlet Oxygen in Dye-Sensitized Photooxidation Reaction of Catecholamines
Kruk, I.
, p. 607 - 613 (2007/10/02)
The photooxidation of catecholamines (adrenaline, noradrenaline and dopamine) sensitized by methylene blue (MB), rose bengal (RB) and fluoresceine (FL) proceed via aminochromes and an indolic pathway.In D2O rate constants of sensitized photooxidation are increased for about 2,7 times over rates in water. 1,3-diphenylisobenzofuran (DPBF), 1,4-diazobicyclooctane (DABCO) and azide anion were more effective inhibitors of the reaction in D2O than in H2O.Superoxide dismutase markedly decreases the rates of photooxidation in H2O and in D2O.Isotope effects and 1O2-quenchers sensitivities indicate that singlet oxygen participates on photooxidation processes of catecholamines.
