共查询到20条相似文献,搜索用时 93 毫秒
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合成了一系列新型的芘标记含溴亲核阴离子的氮杂环卡宾前驱体化合物,与卤化锌配位后获得具有CO2捕获能力以及路易斯酸碱位点的NHC-PDBI-ZnX2(X=Cl、Br、I)催化剂,通过1H NMR、13C NMR、XPS、FT-IR、13C CP-MAS NMR和ICP-AES表征技术对该类催化剂结构和化学性质进行了表征.氮杂卡宾锌配合物被证明是有效的单组分多功能催化剂,对环氧丙烷和CO2的环加成反应显示出较高的催化活性和选择性.最佳活性的NHCPDBI-ZnI2催化剂在120℃、3.0 MPa、2.0 h等较温和条件下,取得98%以上碳酸丙烯酯收率.该催化剂还具有优异的底物普适性和循环使用稳定性,归因于路易斯酸性Zn2+与NHC-PBDI主链形成的强共价键.此外,结合FTIR等表征推测了反应机理,其中NHC-PDBI-ZnX2的卡宾位吸附活化CO2以及路易斯酸碱位点开环的... 相似文献
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设计合成和表征了新型叠氮基官能团化的SIPr(2,6-diisopropylphenyl]imidazolin-2-ylidene)氮杂卡宾铜配合物.这种氮杂卡宾铜配合物既可作为反应底物又可作为催化剂进行自催化的叠氮炔烃3+2环加成反应(CuAAC).通过这种配合物与炔烃的简单自催化反应,在常温常压条件下合成出了一种新型的基于氮杂卡宾铜配合物的超分枝"聚合物",并通过固体核磁、红外光谱、元素分析、原子吸收光谱和X射线光电子能谱对其进行了完整的表征. 相似文献
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设计合成和表征了新型叠氮基官能团化的SIPr(2,6-diisopropylphenyl]imidazolin-2-ylidene)氮杂卡宾铜配合物。这种氮杂卡宾铜配合物既可作为反应底物又可作为催化剂进行自催化的叠氮炔烃3 2环加成反应(CuAAC)。通过这种配合物与炔烃的简单自催化反应,在常温常压条件下合成出了一种新型的基于氮杂卡宾铜配合物的超分枝“聚合物”,并通过固体核磁、红外光谱、元素分析、原子吸收光谱和X射线光电子能谱对其进行了完整的表征。 相似文献
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以脱氢枞胺为原料,经氨基酰化、12位乙酰化、与对甲苯磺酰肼形成对甲苯磺酰腙衍生物,再通过卡宾中间体与C60进行[2+1]环加成反应合成了C60-脱氢枞胺衍生物。目标化合物经IR,UV-Vis,1H NMR,13C NMR,MALDI-TOF MS表征,所得化合物为[6,6]闭环结构C60加成产物。 相似文献
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吴兆轩 Heriberto Diaz Velazquez 闵梦蝶 原晔 Hussein A. Younus 陈建 Bibimaryam Mousavi Francis Verpoort 《化学通报》2015,78(3):220-225
近年来,催化CO2合成精细化学品的研究备受关注。本研究在温和条件下利用金属双氮杂环卡宾催化剂实现CO2与末端炔烃的直接羧化反应,并提出合理的催化机理。首先,合成制备了铜基、银基两种金属双氮杂环卡宾催化剂,实验证明银双氮杂环卡宾配合物具有较好催化活性。通过改变环境条件和底物种类,对反应条件及催化剂底物适应性进行了探究,利用核磁共振谱仪表征产物分子结构并计算直接羧化反应的催化产率。结果表明,适宜催化条件为:1.2eq Cs2CO3作为添加剂、1大气压、室温、无水溶剂和1(mmol)%催化剂用量。银基金属催化剂活性较铜基催化剂高并具有广泛的底物适应性,对苯乙炔的催化产率高达93%;对乙炔气体同样具有良好的催化活性。此类催化剂具有优良的催化活性,能催化合成丙炔酸等重要医药中间体,在工业应用上具有极大潜力和广阔前景。 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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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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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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《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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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