Quinones

It is shown that the condensation of 2,3-dichloro-p-benzoquinone with N-alkyl(aryl)--aminocrotonic acid esters leads, depending on the conditions and the nature of the substituent attached to the nitrogen of the aminocrotonic ester, either to substituted dichlorohydroquinones or to 5-hydroxy-6,7-dichloroindole derivatives. The latter are oxidized by nitric acid to the corresponding o-quinones.See [8] for communication XLIX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 335–338, March, 1971     

Abietane Quinones from Rabdosia serra

Rabdosiu Serra (M4-YId Hara is a chinese traditional medicine for the treatment ofhepatitis. enteritis. acute cholecystitis and dysentery'. The present communicationdescribes the first isolation of three abietane quinone diterpenoids from the herb (Figure1 ). The new abietane quinone, 16-acetoxy-7Q-ethoxyroyleanone I was elucidated. Inaddition. two known abietane quinones, horminone 2, 16-acetoxy-7-0-acetylhorminone 3and 6-sitosterol. stigmasterol. ursolic acid. palmitic acid were identifie…     

Quinones for redox flow batteries

Quinones are electroactive species that have shown great promise for redox flow batteries due to the ability to tune their properties and to act as both negative and positive electrolytes. The following review outlines highlights of work in the last couple of years working to provide materials with higher stability, solubility, and performance. Developments toward stable negolytes have provided opportunities for potential commercial opportunities when paired with alternate chemistries. However, the stability of quinones in high potential electrolytes is still not sufficient and the number of potential quinones limited.     

The Diterpenoid Quinones from Coleus forskohlii

Coleus forskohlii is only distributed in Yunnan and the southern regions of Asia. The decoction of the plant is used in local folk medicine against asthma, cough and bronchitis. Meanwhile, the plant was developed into a new drug for the treatment of asthma, cough, acute and chronic bronchitis several years ago by our group1. It appears that the Coleus is rich source of diterpenoids with different oxygenation patterns2, and six diterpenoids have been isolated from its whole plant distributed i…     

New Reactions of Halogenphosphoranes with Quinones

Abstract

It has not been known up to now that PCl₅ and p-benzoquinone can interact and form stable products. We have established that at the first stage of the reaction phosphorane (I) is formed which further undergoes different transformations depending upon the conditions.     

Bioactivity Profiles of Cytoprotective Short-Chain Quinones

Short-chain quinones (SCQs) have been investigated as potential therapeutic candidates against mitochondrial dysfunction, which was largely thought to be associated with the reversible redox characteristics of their active quinone core. We recently reported a library of SCQs, some of which showed potent cytoprotective activity against the mitochondrial complex I inhibitor rotenone in the human hepatocarcinoma cell line HepG2. To better characterize the cytoprotection of SCQs at a molecular level, a bioactivity profile for 103 SCQs with different compound chemistries was generated that included metabolism related markers, redox activity, expression of cytoprotective proteins and oxidative damage. Of all the tested endpoints, a positive correlation with cytoprotection by SCQs in the presence of rotenone was only observed for the NAD(P)H:quinone oxidoreductase 1 (NQO1)-dependent reduction of SCQs, which also correlated with an acute rescue of ATP levels. The results of this study suggest an unexpected mode of action for SCQs that appears to involve a modification of NQO1-dependent signaling rather than a protective effect by the reduced quinone itself. This finding presents a new selection strategy to identify and develop the most promising compounds towards their clinical use.     

An Improved Reductive Methylation Procedure for Quinones

The reductive methylation of quinones bearing electron donating groups such as hydroxyl or alkoxyl groups proceeds in good yields. The improved conditions greatly extend the scope of this useful reaction.     

Investigation of the Oxidation-Reduction Characteristics of Heterocyclic Quinones

An electrochemical investigation was undertaken into the oxidation–reduction characteristics of heterocyclic quinones including derivatives of indazole, benzimidazole, benzofuran, benzothiazole, and isoquinoline. It was established that the compounds are reduced with the successive irreversible transfer of two electrons. The effect of structural factors and the nature of the heterocycle on the ease of reduction of the compounds is examined.     

可充锂电池醌类化合物电极材料

醌类化合物电极材料具有理论比容量高、结构可设计、成本低廉和绿色可持续等优点,被认为是可充锂电池理想的电极材料。本文介绍了醌类化合物电极材料的分类及其结构特点、电化学工作原理及其电化学性能,对醌类化合物的发展、面临的问题等方面进行了概括,探讨了提高该类电极材料电化学性能的方法,并对醌类化合物电极材料的发展方向进行了展望。     

醌类化合物的超临界流体萃取研究进展

综述了国内近20年来超临界流体萃取技术应用于醌类化合物分离的研究进展,重点介绍了超临界流体萃取技术在中草药中醌类化合物的分析测定方面的应用,分析了影响醌类成分提取效果的主要因素,优化萃取温度和萃取压力能够改善琨类化合物的分离效果,夹带剂的使用则有效地提高了超临界流体的萃取能力。     

Phenols and Quinones from Seeds of Different Iris Species

The seed oils of I.pseudacorus LINN ., I.sibirica LINN ., and I.missouriensis NUTTAL . contain appreciable amounts of phenols, quinones, and resorcinols, substituted with homologous alkyl or alkenyl side chains. The structure elucidation of these compounds is described, and their possible biosynthesis is discussed.     

Two Quinones from the Aerial Parts of Sphallerocarpus gracillis

SPhallerocarpusgracilliS(Boss)K-Pci.istheonlyspeciesofthegenusSPhallerocarpus,mainlydistributedinnortheasternandnorthwesternpartsofChina.IthasbeenusedintraditionalChinesemedicinesinceancienttimesl.Inthispaper,wereportthestructLlreelucidationoftwonewquinonesisolatedfromtheaerialpartsofSPhallerocarpusgracillis.CompoundIwasobtainedasbrown-yellowneedles,m.p.202-204"C.ItsHRMSshowedthemolecularionpeak[M ]atIn/z=402.1680,whichallowedforaC,,H,,O,molecularformula(cafed.402.1679).Thecolorreact…