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171.
Electrochemical detection without derivatization was used to detect thiol-containing degradation products of V-type nerve
agents. Electropolymerization of pyrrole was used for entrapment of the biocatalyst PQQ to produce a sensor. Various parameters
which affect the detection processes such as the type of the supporting electrolyte used during electrodeposition and the
thickness of the polypyrrole film were examined and optimized. Electocatalytic oxidation of thiols by the PPy/PQQ electrode
was strongly affected by the presence of Ca2+ cations during electrodeposition of the PPy/PQQ. Cyclic voltammetry, linear sweep voltammetry and amperometry have been used
for electrode characterization. Amperometric detection of the V-type nerve agent thiol degradation products 2-(dimethylamino)ethanethiol
(DMAET) and 2-(diethylamino)ethanethiol (DEAET) was performed at 0.38 V. Linear calibration plots were observed for these
compounds. The detection limits of 4.5 and 3 μM were obtained for DMAET and DEAET respectively, with sensitivities of 1.18
and 1.37 nA μM−1 cm−2. 相似文献
172.
吡咯喹啉醌含量的非酶系统测定赵永芳,徐宁(武汉大学生命科学学院,武汉,430072)王银善,肖华胜(中国科学院武汉病毒研究所,武汉,430071)关键词吡咯喹啉醌,氧化还原,抗坏血酸,硝基四唑蓝中图法分类号Q554·9毗咯喷淋配(Pqrroloqui... 相似文献
173.
通过4-羟基香豆素与苯甲醛、甲醛和戊醛缩合产生的quinone methide与烯醇硅醚的Diels-Alder反应, 以较高产率合成了一系列含有硅氧基的3,4-二氢-2H,5H-吡喃并[3,2-c][1]苯并吡喃-5-酮衍生物. 用X射线单晶衍射确定了其中5个化合物的空间构型. 利用密度泛函(DFT)方法计算反应物之间的前线分子轨道相互作用, 对反应的区域选择性进行了研究, 计算结果与实验值相符. 相似文献
174.
Xiaomei Yang Ying Wang Chaofeng Zhang Tao Fang Lipeng Zhou Wei Zhang Jie Xu 《Journal of Physical Organic Chemistry》2011,24(8):693-697
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. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
175.
建立了用丹磺酰氯定性鉴定吡咯喹啉醌的薄层色谱法。甲基营养菌No.2培养液经二乙氨基乙基交联葡聚糖凝胶A-25离子交换剂、Sep-Pak C18 Cartridge纯化后,可获得纯度92%以上的吡咯喹啉醌(PQQ)粉末。在碱性条件下丹磺酰氨(DNS-Cl)可与PQQ生成具有特征性的DNS-N-PQQ荧光衍生物,将其点祥于聚酰胺薄膜上,经正庚烧-正丁醇-醋酸(体积比3:3:1)系统展开,Rf值为0.7 相似文献
176.
Cemil Ibis Amac Fatih Tuyun Zeliha Ozsoy-Gunes Sibel Sahinler Ayla Maryna V. Stasevych Rostyslav Ya. Musyanovych 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):955-966
Abstract A novel series of substituted 1,4-naphthoquinone derivatives were synthesized and evaluated for their antibacterial and antifungal activity. The structures of the novel products were characterized by spectroscopic methods. Among the tested compounds, 2,2′,3,3′-alkoxy substituted naphthoquinones, S,O-substituted naphthoquinone, and N,S-substituted naphthoquinone derivatives are the most potent antifungals against C. tenuis. 2,3-Thio-2′,3′-alkoxy substituted naphthoquinones are the most effective antifungal compounds against A. niger. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
177.
José Villamizar Federico Plata Nieves Canudas Eleonora Tropper Juan Fuentes Angel Orcajo 《合成通讯》2013,43(3):311-320
A facile access to optically active (+)‐ent‐chromazonarol ent‐1, isolated from the sponge Disidea pallescens, is reported from commercially available (+)‐manool 4. 相似文献
178.
Jürgen Schmidt Dietmar Kuck Katrin Franke Haider Sultani Annegret Laub Ludger A. Wessjohann 《Journal of mass spectrometry : JMS》2019,54(6):549-556
Long‐chain ferulic acid esters, such as eicosyl ferulate ( 1 ), show a complex and analytically valuable fragmentation behavior under negative ion electrospay collision‐induced dissociation ((?)‐ESI‐CID) mass spectrometry, as studied by use of a high‐resolution (Orbitrap) mass spectrometer. In a strong contrast to the very simple fragmentation of the [M + H]+ ion, which is discussed briefly, the deprotonated molecule, [M – H]?, exhibits a rich secondary fragmentation chemistry. It first loses a methyl radical (MS2) and the ortho‐quinoid [M – H – Me]‐? radical anion thus formed then dissociates by loss of an extended series of neutral radicals, CnH2n + 1? (n = 0–16) from the long alkyl chain, in competition with the expulsion of CO and CO2 (MS3). The further fragmentation (MS4) of the [M – H – Me – C3H7]? ion, discussed as an example, and the highly specific losses of alkyl radicals from the [M – H – Me – CO]‐? and [M – H – Me – CO2]‐? ions provide some mechanistic and structural insights. 相似文献
179.
PQQ对四氯化碳和乙醇引起大鼠肝损伤的保护作用 总被引:1,自引:0,他引:1
将大鼠分成5组,采用灌胃方式,连续14d分别灌入PQQ-水溶液,PQQ-乙醇溶液,乙醇溶液和生理盐水溶液(阴性和阳性对照两组),尔后,除阴性对照组外,均灌入CCL4,检测结果表明:PQQ可明显降低大鼠血清中GPT,GOT以及肝组织中MDA的含量,可减少轻肝细胞水变性,脂肪变性和肝细胞坏死的程度,由此说明:PQQ对CCl4和乙醇引起的肝损伤有一定的保护作用。 相似文献
180.
用半经验的AM1,abinitio(HF/3-21G,HF/6-31G^*),及密度泛函[B3LYP/6-31G^*,B3LYP/6-311G(d,p)]方法对1,4-苯酯及其阴离子的结构与性质进行了研究。在此基础上用AM1及BLYP/6-31G(d,p)方法对泛醌Q~0,用AM1方法对泛醌Q~1,泛醌Q~2及其阴离子的结构与性质进行了研究。研究结果表明,由于取代基的影响,泛醌的环平面发生了扭曲,环上原子不再位于同一平面上。结构的变化导致了电子分布发生了变化,并由此导致了偶极矩随6位上取代基的增大而增大。随着6位支链的增长,泛醌的电离势逐渐减小而电子亲和势逐渐增大,泛醌传递电子的能力增强。在上述研究的基础上,对1,4-苯醌及泛醌的自交换电子转移反应过程进行了过程,计算了反应的内重组能,溶剂重组能及电子转移速率常数。结果表明内重组能的大小与取代基的长短无直接关系,而与得电子前后醌的结构变化程度密切相关。除高频振动的变化外,低频振动的变化对内重组能也有显著的贡献。计算所得1,4-苯醌自交换电子转移反应速率常数与实验值相符得很好。 相似文献