526-86-3Relevant articles and documents
Steric effects of substituents of quinones on the oxygenation of ethylbenzene catalyzed by NHPI/quinone and the catalytic oxidation of ascorbate
Yang, Xiaomei,Wang, Ying,Zhang, Chaofeng,Fang, Tao,Zhou, Lipeng,Zhang, Wei,Xu, Jie
, p. 693 - 697 (2011)
The substituents of quinones play an important role in modulating the kinetics of the electron- and proton-transfer reaction. In this paper, the steric effects of substituents of quinones on their catalytic performance were studied in the oxidation of ethylbenzene and ascorbate. The substituents limited the addition of the free radicals to the C=C double bonds of the quinone ring because of the steric hindrance. On the other hand, too many substituents hindered the contact between the active site (C=O) of quinone and the reactant. So, the quinones with two substituents presented better catalytic performance than those with more or less substituents. These results will be helpful in designing the quinone compounds for drugs and in understanding the catalytic behavior of quinones in biochemistry.
Rabinovich
, p. 140 (1967)
Design, synthesis, and rearrangement studies of gem-dimethyl containing cage systems
Kotha, Sambasivarao,Cheekatla, Subba Rao
, (2020)
A variety of functionalized cage compounds and D3-trishomocubane derivatives have been assembled via the Diels–Alder strategy, with reductive cleavage of the cyclopropane ring and metal promoted ring rearrangement as key steps. We have installed the gem-dimethyl moiety on the norbornane ring system containing a cage framework by a late-stage synthetic manipulation involving the hydrogenolysis of the cyclopropane ring with the aid of Adams’ catalyst (PtO2). Several cage molecules containing methyl substituents were synthesized by starting with inexpensive and commercially available materials such as 2,3-dimethylhydroquinone, Zn/AcOH, and endo-dicyclopentadiene. These cage pentacycloundecane frameworks assembled here are difficult to synthesize by conventional routes. Some of these gem-dimethyl cage systems and D3-trishomocubane derivative was firmly supported on the basis of single-crystal X-ray diffraction studies.
Neuroprotection in the MPTP parkinsonian C57BL/6 mouse model by a compound isolated from tobacco
Castagnoli, Kay P.,Steyn, Stefanus J.,Petzer, Jacobus P.,Van Der Schyf, Cornelis J.,Castagnoli Jr., Neal
, p. 523 - 527 (2001)
Epidemiological evidence suggests a lower incidence of Parkinson's disease in smokers than in nonsmokers. This evidence, together with the lower levels of brain monoamine oxidase (MAO) activity in smokers and the potential neuroprotective properties of MAO inhibitors, prompted studies which led to the isolation and characterization of 2,3,6-trimethyl-1,4-naphthoquinone (TMN), an MAO-A and MAO-B inhibitor which is present in tobacco and tobacco smoke. Results of experiments reported here provide evidence that this compound protects against the MPTP-mediated depletion of neostriatal dopamine levels in the C57BL/6 mouse. These results support the hypothesis that the inhibition of MAO by constituents of tobacco smoke may be related to the decreased incidence of Parkinson's disease in smokers.
Aerobic Oxidation of Dihydroxyarenes Substrates Catalyzed by Polymer-Supported RuII-Pheox/Silica-Gel: A Beneficial Route for Purification of Industrial Water
Abu-Elfotoh, Abdel-Moneim
supporting information, p. 236 - 243 (2022/04/09)
A broad class of dihydroxyarenes were easily oxidized by aerobic oxygen to quinone products in excellent yields under the catalytic effect of polymer-supported RuII-Pheox/silica-gel catalyst. By using this combined catalyst, hydroquinone and catechol derivatives with electron-donating groups were easily oxidized by molecular oxygen to quinone products in 90% to >99% yield, while in the case of electron-withdrawing group, only 70% was obtained. The biologically useful 1,4-Naphthoqinone products were obtained in 83% to 90%. The catalyst was easily obtained and reused many times without a significant decrease in reactivity. Interestingly, a sample of industrial water contaminated with phenolic compounds was subjected to aerobic oxidation by using this catalyst, and the resultant quinones were detected within one day and the catalyst was removed and reused several times with different contami-nating samples with the same efficiency. Other catalytic oxidations by using this promising catalyst were investigated.
Plastoquinone analogs: a potential antimicrobial lead structure intensely suppressing Staphylococcus epidermidis and Candida albicans growth
Ataman, Merve,Ozbek-Celik, Berna,Bayrak, Nilüfer,Matarac?-Kara, Emel,Tuyun, Ama? Fatih,Y?ld?r?m, Hatice,Y?ld?z, Mahmut
, p. 1728 - 1737 (2021/08/06)
The aim of this study was to evaluate the antimicrobial activity of twenty-five Plastoquinone analogs synthesized previously in a panel of seven bacterial strains (three Gram-positive and four Gram-negative bacteria) and three fungi. PQ1, which does not contain any substituent(s) on the phenyl ring, was the most potent compound against Staphylococcus epidermidis (8-fold more potent than Cefuroxime, MIC = 1.22 μg/mL). The antifungal profile of all Plastoquinone analogs indicated that three analogs (PQ1, PQ2, and PQ7) displayed the best antifungal activity against Candida albicans, which was about the same activity with the reference standard (MIC = 4.88 μg/mL). The structure-activity relationship study was also carried out to reveal important chemical features. After probing twenty-five Plastoquinone analogs for a potential antimicrobial lead structure, two analogs (PQ1 and PQ25) were selected for further investigation for biofilm evaluation. Based on the tests performed, there was a significant positive correlation between inhibition of the biofilm attachment and time. The results showed that both analogs (PQ1 and PQ25) are able to reduce biofilm mass. Finally, these findings endorse us further efforts to optimize two phenotypes of the Plastoquinone analogs (PQ1 and PQ25) to develop potential antimicrobial drug candidates. [Figure not available: see fulltext.]
Strategies towards potent trypanocidal drugs: Application of Rh-catalyzed [2?+?2?+?2] cycloadditions, sulfonyl phthalide annulation and nitroalkene reactions for the synthesis of substituted quinones and their evaluation against Trypanosoma cruzi
Wood, James M.,Satam, Nishikant S.,Almeida, Renata G.,Cristani, Vinicius S.,de Lima, Dênis P.,Dantas-Pereira, Luiza,Salom?o, Kelly,Menna-Barreto, Rubem F.S.,Namboothiri, Irishi N.N.,Bower, John F.,da Silva Júnior, Eufranio N.
, (2020/06/23)
Rhodium-catalyzed [2 + 2 + 2] cycloadditions, sulfonyl phthalide annulations and nitroalkene reactions have been employed for the synthesis of 56 quinone-based compounds. These were evaluated against Trypanosoma cruzi, the parasite that causes Chagas disease. The reactions described here are part of a program that aims to utilize modern, versatile and efficient synthetic methods for the one or two step preparation of trypanocidal compounds. We have identified 9 compounds with potent activity against the parasite; 3 of these were 30-fold more potent than benznidazole (Bz), a drug used for the treatment of Chagas disease. This article provides a comprehensive outline of reactions involving over 120 compounds aimed at the discovery of new quinone-based frameworks with activity against T. cruzi.
