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以阴离子聚合法合成的窄分布聚苯乙烯(NDPS)进行氯甲基化后,再与由基团转移聚合法合成的活性聚甲基丙烯酸甲酯(PMMA)进行大分子反应,得到了主链为聚苯乙烯,支链为聚甲基丙烯酸甲酯的接枝共聚物(PStgPMMA);探讨了聚合物的合成条件,GPC测试结果表明,得到的接枝共聚物的分子量和设计分子量相近且主链和支链分子量均可较好的控制.利用扫描电镜、核磁和红外技术对PStgPMMA的形态、结构进行了表征. 相似文献
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采用基团转移聚合、阴离子聚合以及高分子偶合反应的方法,合成了一种结构明确、链长均匀和分子量可控的聚苯乙烯接枝聚甲基丙烯酸甲酯。主链聚苯乙烯由阴离子聚合得到,并进行溴甲基化。支链活性聚甲基丙烯酸甲酯由基团转移聚合制备。经偶合反应后得到分子量为3×104~7×104、多分散性指数D为1.2~1.4的接枝共聚物。溴甲基化聚苯乙烯和活性聚甲基丙烯酸甲酯的偶合反应活性随分子量的增大而降低,理想的反应温度为-20℃。用1HNMR、GPC和DSC表征接枝产物。和均聚物相比,共聚物的玻璃化温度较低。 相似文献
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用链长分布不同的活性聚苯乙烯子聚物与二乙烯基苯进行阴离子嵌段共聚,合成了一系列两相模型交联网络。以作者等提出的方法测定了所合成网络的结构非均一因子Z。实验测定的网络结构非均一因子Z与交联前聚苯乙烯活性链的分子量分布宽度指数d之间有平行的相应变化规律,表明所给予的非均一因子Z的物理意义是合理的。同时说明,子聚物链长分布较宽时,在网络的高交联区中除了二乙烯基苯外,还有一些对溶胀无贡献的子聚物以悬挂链的形式存在。 相似文献
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在常压、惰性气体保护下,以正丁基锂引发苯乙烯进行阴离子聚合,并用少量甲基丙烯酸缩水甘油酯(GMA)进行终端共聚,制得了侧基含有环氧基团的聚苯乙烯-聚甲基丙烯酸缩水甘油酯嵌段共聚物.用GPC、FT-IR、1H-NMR及盐酸-二氧六环银量法对共聚物进行了分析,并考察了GMA用量、终端共聚的反应温度及时间对环氧侧基数量的影响.结果表明:在少量四氢呋喃和氯化锂的存在下,1,1-二苯基乙烯(DPE)"盖帽"的聚苯乙烯阴离子活性种在甲苯溶剂中可引发GMA单体聚合反应,所得聚合物分子链中环氧侧基数量可根据需要进行调节.适宜的终端共聚反应温度和时间分别为-65℃和0.5 min. 相似文献
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通过由萘钠引发得到的聚苯乙烯"活性"双阴离子与C70的反应,合成了哑铃状C70-聚苯乙烯高分子衍生物.产物经UV-Vis,FTIR,GPC,1HNMR,13CNMR,SEM,XRD,TGA和DSC等方法进行表征.GPC测得C70-PS衍生物与其母体PS具有相近的分子量.TGA分析表明,得到C70的含量接近PS链两端各键合一个C70分子,形成线型的哑铃状结构. 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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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 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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KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
The review contains a concise historical account and information on the most significant researches undertaken by the staff
at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry
of Heterocyclic Compounds.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008. 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