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硝基化合物的不对称迈克尔加成反应 总被引:1,自引:0,他引:1
从以下三方面对硝基化合物的不对称迈克尔加成反应进行了较为详细的综述: (1)手性催化剂催化的迈克尔加成,(2)共轭硝基物与手性亲核试剂的迈克加成 ,(3)脂肪族硝基物对手性迈克加成受体的迈克尔加成。 相似文献
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以PEG200为结构诱导剂,用诱导-陈化方法合成了枝状纳米结构氧化锆。电导率的测定表明,PEG200对特殊形貌氧化锆的形成具有诱导和调控作用。用SEM、XRD、UV等对所得氧化锆的形貌、结构和紫外吸收特性等的表征表明,合成的枝状氧化锆以四方相结构为主。产物除了在235nm处有较强的吸收外,在300nm附近还可观察到多重的吸收。 相似文献
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枝状文石型碳酸钙的仿生合成及在PVC中的应用 总被引:1,自引:0,他引:1
利用生物矿化原理,以聚丙烯酸(PAA)为有机基质,采用碳化法合成了具有枝状形貌的文石型碳酸钙粒子.通过场发射扫描电镜(FESEM)、X射线衍射仪(XRD)和傅里叶变换红外光谱仪(FTIR)等检测手段研究了产物的结构和形貌,并初步探讨了粒子的生长机理.结果表明,在文石型碳酸钙粒子的合成中,有机基质和反应温度是非常重要的参数.同时将该产品填充于聚氯乙烯(PVC)中,测定了PVC塑料的力学性能和加工性能. 相似文献
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γ-MnOOH multipods were synthesized by a low temperature hydrothermal method. The synthetic procedure is based on the use of PEG200 to reduce KMnO4 upon controlling the volume of PEG200. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) were used to characterize the products. All pods of them are single crystals, the diameter of each pod is about 40~120 nm and the length is about 800~2 400 nm. A possible formation mechanism was proposed that the intermediate products with a lamellar morphology curled into γ-MnOOH nanorods during the reaction process at first, and then γ-MnOOH multipods formed for the multi-nuclei growth on the tips of the γ-MnOOH nanorods when they were good crystallization. 相似文献
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模板法制备枝状Pt纳米线 总被引:10,自引:2,他引:8
一维纳米材料的制备是近年来纳米材料的研究热点. 利用具有纳米尺度的孔洞阵列模板沉积各种材料构筑纳米线的方法具有制备简便和成本较低等优点[1,2]. 常用的模板有多孔阳极氧化铝(AAO)、多孔硅和聚合物等, 其中AAO模板具有耐高温, 绝缘性好, 孔洞分布均匀, 孔径、孔深大小可控等特点, 是模板法研究的热点. 通过模板法电化学沉积制备各种金属纳米线已有很多报道[3~8], 本研究小组也曾报道了模板法电化学沉积Au等纳米线的制备及性质[9~12], 但用该方法制备的金属纳米线都为单一的线状结构. 组成当代大规模集成电路的基本器件一般具有3个或3个以上的电极. 单一的线状结构纳米线, 不能满足纳米电子学对纳米材料和纳米器件性能研究的需要. 在纳米器件的特性研究和探索中, 枝状或Y形纳米结的制备有重要的意义, 它是纳米器件从理论到实用化的必备条件. Sui等[13]用模板法成功制备了枝状碳纳米管, 但用AAO模板制备枝状金属纳米线的研究至今还未见报道. 本文通过控制铝片的阳极氧化条件, 先制备出具有分枝状孔洞结构的AAO模板, 再用电化学法沉积金属Pt, 实现了枝状Pt纳米线的可控生长. 这对其它金属枝状纳米线的制备以及进一步掺杂、构筑纳米原型器件等具有显著的实用价值. 相似文献
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本文简要介绍了分子内的自由基加成反应及其在环状化合物(包括碳环,杂环和多环天然产物)合成中的应用。 相似文献
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为了探索乙二胺绿色合成的新工艺,采用自制的负载型双组分复合金属氧化物Ni O/Cu O/Al2O3为催化剂,对乙二醇进行催化氨化制备乙二胺,用气相色谱法对反应物进行分析检测,采用X射线衍射仪(XRD)、X射线光电子能谱分析仪(XPS)等技术手段对催化剂结构进行了表征。通过考察催化剂组成、物料比、温度和时间等因素对反应的影响,确定了合成乙二胺的最佳工艺条件:催化剂活性组分n(Ni)∶n(Cu)=3∶1、催化剂加入量3%、氨醇质量比4∶1、反应温度180℃、反应压力0.6 MPa、反应时间4 h,乙二胺的选择性达56.7%,乙二醇转化率达68.6%。与传统的二氯乙烷法相比较,本工艺更清洁友好。 相似文献
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A facile triphenylphosphine-catalyzed Michael addition of alcohols to acrylic compounds was described. The reaction was carried out in open air at refluxing temperature in the presence of 10 mol% PPh3. Michael addition of saturated and unsaturated alcohols to acrylonitrile or acrylates has been examined. The reaction gave β-alkoxy derivatives with isolated yields of 5%-79%. PPh3 is cheaper and more stable than those trialkylphosphines previously used for the similar reactions, and the products can be easily separated from the reaction mixture via distillation. 相似文献
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综述了近十年来,金鸡纳碱、硫脲、手性离子液体、季铵盐、脯氨酸和葡萄糖类衍生物等有机小分子在催化查尔酮的不对称Michael加成反应中的应用.有机小分子催化的机理大部分都是通过氢键、离子键等与底物相互作用而使其有较好的对映选择性. 相似文献
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Bi‐Shuang Chen Dr. Verena Resch Dr. Linda G. Otten Prof. Dr. Ulf Hanefeld 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(7):3020-3030
The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important β‐hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent enantioselectivities were achieved with this method. Deuterium labeling studies demonstrate that a Michael hydratase catalyzes the water addition exclusively with anti‐stereochemistry. 相似文献
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《Helvetica chimica acta》2017,100(7)
New nitrile‐containing gem‐bisphosphonates as drug candidates for the contrast of osteoporosis are presented, their synthesis being based on the metal catalyzed Michael conjugate addition of trimethylsilyl cyanide to unsaturated bisphosphonate precursors. Zn(OT f)2 turned out to be the most efficient metal catalyst for the reaction enabling the formation of β‐nitrile substituted bisphosphonates in good yields. The corresponding final bisphosphonic acids bearing the nitrile moiety were obtained by deprotection of the ethyl ester moiety. They showed aggregation properties in water due to their amphiphilic nature and will be evaluated in order to assess their biological anti‐osteoclast activity. 相似文献
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Vicarious Michael Addition 总被引:1,自引:0,他引:1
Zhong Biao ZHANG Dillip K. MOHANTY 《中国化学快报》2006,17(4):561-564
C-H bond can undergo vicarious Michael addition reaction (VMA) with double-activated double bond in the absence of strong base and catalyst under mild conditions. Intramolecular H-bonding, electron-withdrawing inductive effect, and steric hindrance at α-position of nucleophile facilitates C-H addition over N-H addition. By using VMA, high branching multiplicity, novel branching pattern, controllable density and distribution of functional groups can be envisioned for novel dendrimer synthesis. 相似文献