An HPLC method has been developed which enables the quantification of low levels of a catechol derivative and a quinone adduct of paroxetine in the presence of excess drug substance. Due to its inherent instability, the paroxetine quinone adduct is not available as a pure compound so that an indirect method was developed for its quantification. This procedure is based on the assumption that one...

Amoeba mitochondria possess a respiratory chain with two quinol-oxidizing pathways: the cytochrome pathway and the cyanide-resistant alternative oxidase pathway. The ADP/O method, based on the non-phosphorylating property of alternative oxidase, was used to determine contributions of both pathways in overall state 3 respiration in the presence of GMP (an activator of the alternative oxidase in ...

The concept of the mode of biological action of quinones as bioreductive alkylating agents is presented. The focus of this discussion is primarily upon the structural features which would facilitate quinonemethide formation (alkylating agent) from the reduced quinone (hydroquinone). A survey of the naturally occurring quinone field was carried out and those members which can be catalogued as po...

A highly precise coulometer is described which permits time integration of currents totaling 100 coulombs or more with a precision of about 1 part in 100,000. The current to be integrated oxidizes hydroquinone in an electrolysis cell, producing quinone and acid. The quinone is t hen reduced by constant-current coulometric titration, the end point being indicated by hydrogen-ion concentration me...

The title compound, C(20)H(10)Cl(6)O(2), a quinone derivative, was obtained by the irradiation of 2,3,5,6-tetra-chloro-benzo-quinone and 4,4'-(ethene-1,1-di-yl)bis-(chloro-benzene). The six- and four-membered rings are fused in a cis configuration. The dihedral angle between them is 53.4 (3)°.

12-Hydroxy-9(10-->20)-5aH-abeo-abieta-1(10),8(9),12(13)-triene-11,14-dione (quinone 2) served as the dienophile in numerous intermolecular Diels-Alder reactions. These cycloadditions were conducted either thermally (including microwave heating) or with Lewis acid activation. While most dienes reacted with quinone 2 in good chemical yield, others were incompatible under the experimental conditio...

Experimental studies of the "extended toxicity" of substituted phenols are mainly of two types: the toxicity due to phenoxyl radical formation and the toxicity caused by metabolites, for example, the formation of quinones. Quantitative structure-activity relationship (QSAR) studies of phenol toxicity have dealt with the formation of phenoxyl radicals using bond dissociation enthalpy (BDE) of pa...

Previously, it has been demonstrated that microsomal, mitochondrial and nuclear enzymes isolated from the liver of male Sprague-Dawley rats catalyzed the oxidation of diethylstilbestrol (DES) to DES quinone. In the present study we have shown that diallyl sulfide (DAS) inhibits the oxidation of DES to DES quinone in all three subcellular fractions (microsomes, mitochondria and nuclei) isolated ...

Huang, H. 2017. Quinone-Pyrrole Dyad Based Polymers for Organic Batteries. From Design to Application. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1483. 73 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-554-9832-0. Organic electrode materials are finding increasing use in energy storage devices due to their attractive properties ...

The central photochemical reaction in photosystem II of green algae and plants and the reaction center of some photosynthetic bacteria involves a one-electron transfer from a light-activated chlorin complex to a bound quinone molecule. Through protein engineering, we have been able to modify a protein to mimic this reaction. A unique quinone-binding site was engineered into the Escherichia coli...