共查询到20条相似文献,搜索用时 484 毫秒
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发展环状化合物的高效合成方法对药物分子、天然产物及其他功能有机分子的合成具有重要意义.近年来,叔膦促进下两种亲电试剂之间的环化反应,由于具有原料简单易得、反应条件温和、且无需金属参与等优点,同时为多种碳环及杂环化合物的合成提供了高效的新途径,因而受到了合成化学家的广泛关注.这类反应通常经过叔膦对亲电试剂进行亲核加成,产生两性离子活性中间体这一关键步骤来完成.根据两性离子的不同来源,综述了叔膦促进下缺电子联烯、Morita-Baylis-Hillman烯丙基化合物、缺电子烯烃与其他亲电试剂之间的环化反应. 相似文献
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现代医学研究证实,小檗碱具有显著的降糖活性和临床安全性。目前,临床应用的降糖药物能够有效控制血糖,但使用不方便,副作用的问题难以避免,且对胰岛素分泌不足、胰岛素抵抗等问题研究少之甚少。本文以小檗碱为先导化合物,对其C(9)位进行结构修饰,并在相应的位点引入具有抗氧化作用的硫辛酸,合成了小檗碱C(9)位硫辛酸酯及其类似物,希望能够得到一种具有双功能双位点的新型降糖药物,达到修复和改善胰岛功能的目的。中间体9-O-取代基类BBR的合成是反应中关键一步,通过量子化学计算比较了三种试剂1,2-二溴乙烷、2-溴乙醇、环氧乙烷的亲电反应能力,为后续中间体的合成工艺提供初步理论依据。 相似文献
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LI Cheng-wei WANG Fu-an QI Tao WANG Rui-lin TANG Xiao-hong ZHANG Yong-qiang 《高等学校化学研究》2009,25(4):532-536
A new green technique for producing chromic acid via an electrosynthesis method was studied.The kinetic experiments were carried out on the direct electrosynthesis reaction of chromic acid from sodium dichromate in a self-made electrosynthesis reactor with a multiple-unit metal oxides combination anode,a stainless steel cathode,and a reinforcing combination Nafion?324 cation exchange membrane.The apparent kinetic data were experimentally measured at different reaction time under different reaction condition... 相似文献
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The possibility of using of molecular oxygen as a mediator in electrosynthesis of metal nanoparticles by reduction of their ions and complexes in aprotic media was demonstrated by the example of electrosynthesis of gold nanoparticles by reduction of Au(I) in DMF. 相似文献
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A theoretical study of the effect of the electrode structure on the electrosynthesis in hydrophobized electrodes (HPE) for a case of further electrochemical conversion of the target product is performed by the example of nitromethane electroreduction to methyl hydroxylamine followed by its reduction to methylamine. The effect of the electrode structure on the selectivity of electrosynthesis in HPE was shown to be related to the effective diffusivity and conductivity. 相似文献
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Zhihua Xu Jianming Wang Wenqu Mao Weichun He Quanqi Chen Jianqing Zhang 《Journal of Solid State Electrochemistry》2007,11(3):413-420
The effects of ultrasound on the direct electrosynthesis of solid K2FeO4 and the anodic behaviors of pure iron were investigated, and the physical properties of samples were characterized by means
of X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. The experimental results
showed that the existence of ultrasound can decrease the formation potential of ferrate(VI) and the passivation extent of
iron anode, and this leads to higher current efficiency for the direct electrosynthesis of solid ferrate(VI) at 65 °C in 14 M
KOH solution. It was also found that, in the experimental scope suitable ultrasonic power (14.6 W), shorter electrolysis duration
and smaller electrolysis current can improve the apparent current efficiency of the electrosynthesis, and the largest current
efficiency under suitable experimental conditions reached 77.2%. 相似文献
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A. K. Evseev M. Sh. Khubutiya M. M. Gol’din A. G. Volkov A. A. Koldaev 《Russian Journal of Electrochemistry》2008,44(8):901-909
The method of indirect electrochemical generation of active oxygen in the persulfate form is developed. It is based on the oxidation of dilute aqueous sulfate solutions and can be used in the hypoxic states therapy. Data on the relationship between the biological activity of synthesized persulfate solutions and their electrosynthesis parameters and redox potentials are used for optimization of electrosynthesis conditions. Bloodcompatible oxidation solutions capable of detoxifying blood containing endo-and exotoxicants are synthesized. 相似文献
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Potapova G. F. Kasatkin E. V. Panesh A. M. Lozovskii A. D. Kozlova N. V. 《Russian Journal of Electrochemistry》2004,40(11):1193-1197
A combination of electrochemical and physicochemical methods is used to investigate electrocatalytic and corrosion properties of nonplatinum materials in a direct hydrogen peroxide electrosynthesis by the oxygen ionization. A modifying action of ozone and hydroquinone added in solution is established. Surface properties of the electrocatalysts are studied. Presumably, the electrosynthesis occurs via a mixed path, which includes direct oxygen electroreduction catalyzed by redox processes involving surface groups and chemical oxidation processes. 相似文献
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Templated electrosynthesis is a simple and versatile method that has been widely used to form nanomaterials and porous structures in materials science. The technique permits dimension-controlled materials synthesis. A variety of templates have been employed to define the morphology of conductive materials in electrodeposition. The formation of those materials has triggered intensive study and development of various novel properties and potential applications. This review presents recent advances in templated electrosynthesis as a method to fabricate nanomaterials and porous structures. 相似文献
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将间接电合成苯甲醛与电还原马来酸制备丁二酸的过程有机结合, 构建了一个新的成对电解体系, 即在隔膜电解槽中, 以纯Pb为阴极, PbO2/Pb为阳极, 硫酸溶液为介质, 在施加超声波的条件下, 阳极氧化Ce3+为Ce4+, 阴极还原马来酸生成丁二酸; 同时, 在槽外采用Ce4+氧化甲苯生成苯甲醛. 实验结果表明, 阴极和阳极电解的平均电流效率分别为92.71%和87.81%, 总的电流效率高达180.52%; 且Ce4+槽外氧化甲苯为苯甲醛的收率为95.78%, 马来酸电还原为丁二酸的转化率为92.09%; 电解的槽电压与单一电解氧化Ce3+相比降低了0.25 V. 相似文献
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石墨电极直接电氧化合成D-阿拉伯糖 总被引:1,自引:0,他引:1
本文报道采用石墨电极直接电氧化D_葡萄糖酸钠(NaGL)合成D_阿拉伯糖研究结果.研究了葡萄糖酸钠浓度、电解电压、温度及电解液组成对电流效率和合成产率的影响。同时指出采用液体电解池进行恒电位电解,其效果比恒电流电解法更好 相似文献