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以酰腙为配体钒的单核、双核配合物因其结构丰富、生物活性多样而引起广泛关注。目前该领域新配合物的合成、表征和生物活性的研究甚为活跃。本文回顾了近年来钒酰腙配合物的研究状况,主要从以下三个方面进行综述:(1)钒酰腙配合物的合成方法;(2)此类配合物的配位模式;(3)一些单、双核钒酰腙配合物抗变形虫,抗肿瘤,类胰岛素,抑制Na+, K+-ATP酶,与DNA作用的生物活性。文中着重阐述了钒酰腙化合物的结构和生物活性之间的关系。此外,还提出了钒酰腙配合物研究领域的不足之处并对其今后发展方向进行了展望。 相似文献
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《中国科学:化学》2017,(2)
自19世纪90年代以来,钒配合物的药物发现及其基础研究有了很大的进展,但仍然存在很多亟待解决的问题.本文综述了钒配合物的抗肿瘤、抗糖尿病作用和分子机制,及其潜在新作用——抗阿尔茨海默症的作用,也介绍了钒配合物的毒性作用及其机制研究.另外,本文在阐明其药理作用和毒性作用分子机理的基础上,综述了钒配合物的理性药物设计,包括基于与靶蛋白作用的钒配合物、基于BMOV先导化合物的钒配合物和基于抗氧化策略的钒配合物等.未来抗糖尿病钒配合物的理性药物设计的关键仍是如何平衡其潜在毒性与抗糖尿病药理活性,而通过抗氧化策略的钒配合物设计或许是解决这一关键问题的有效途径. 相似文献
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合成了2种羟胺氧钒配合物--缬(亮)氨酸羟胺氧钒, 并通过元素分析、红外光谱、紫外光谱、热重分析及X射线单晶衍射对其结构进行了表征. 采用PTP1B酶筛选模型评价了它们及相关配合物的PTP1B酶抑制活性. 实验结果表明, 这2种配合物同属于三斜晶系, P1空间群, 中心钒原子与7个配位的氮氧原子形成扭曲的五角双锥构型, 进而通过氢键作用形成三维晶体结构. 这2种配合物对PTP1B酶都表现出抑制活性, 亮氨酸羟胺氧钒在浓度为20 μg/mL时对PTP1B酶的抑制率达到90.51%. 相似文献
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钒系烯烃聚合催化剂在工业上有着不可替代的位置,它可用于制备高活性窄分布的聚合物、乙烯与α-烯烃共聚物和间规聚丙烯等。但由于实验手段难以确定钒催化剂活性物种的结构,进一步对催化机理的确认及催化剂结构的改进十分困难。本文运用密度泛函方法对水杨醛亚胺钒配合物催化乙烯聚合的活性物种结构进行了理论研究。对多种活性物种模型的比较研究结果表明,对此催化反应最有利的活性物种为中性双金属物种a1, a1结构中包含两个连接铝原子与钒中心的氯桥结构。研究同时表明,助催化剂AlEt2Cl的存在不仅加速了钒配合物前体的烷基化反应,同时其对活性物种a1结构中氯桥的形成至关重要。最后还研究了该催化体系的链终止反应机理。 相似文献
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用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%. 相似文献
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Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields. 相似文献
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The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. 相似文献
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A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL. 相似文献
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Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products. 相似文献
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A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions. 相似文献
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《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative. 相似文献
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Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner. 相似文献