143 resultados para ARYL-GRIGNARD


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提出了由β,β-1,3-亚丙二硫基-α,β-不饱和芳酮类化合物(1)与苄基氯化镁及烯丙基溴化镁加成所得的醇(2)在BF_3·Et_2O催化下脱水生成共轭烯烃(3)新的合成途径,合成了13种新化合物,结构经~1H N-MR、IR、UV及元素分析等确证.并对这一新合成途径的反应机制进行了讨论.

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β,β-1,5-亚丙二硫基-α,β-不饱和酮2b和2-甲基烯丙基氯化镁加成可得醇3b.在BF_3·Et_2O催化下,3b经分子内环合芳构化生成芳硫醚5b.2和烯丙基溴化镁反应得醇4,4在BF_3·Et_2O催化下经β-消除脱水生成共轭多烯类化合物6.二硫缩醛基以环和非环结构及环的大小对2与烯丙基Grignard试剂加成物在酸催化下的反应取向有重要影响.

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The crystallization and melting behaviour of poly(aryl-ether-ether-ketone) (PEEK) in blends with another polymer of the same family containing a bulky pendant phenolphthalein group (PEK-C) have been investigated by thermal methods. The small interaction energy density of the polymer pair (B = -8.99 J/cm3), evaluated from equilibrium melting point depression, is consistent with the T(g) data that indicate partial miscibility in the melt. Two conjugated phases are in equilibrium at 430-degrees-C: one is crystallizable and contains about 35 wt% of PEK-C; the other, containing only 15 wt% of PEEK, does not form crystals upon cooling and it interferes with the development of spherulites in the sample. The analysis of kinetic data according to nucleation theories shows that crystallization of PEEK in the explored temperature range takes place in Regime III and that a transition to Regime II might be a consequence of an increase in the amount of non-crystallizable molecules in the PEEK-rich phase. A composition independent value of the end surface free energy of PEEK lamellae has been derived from kinetic data (sigma-e = 40 +/- 4 erg/cm2) in excellent agreement with previous thermodynamic estimates. A new value for the equilibrium melting temperature of PEEK (T(m)-degrees = 639 K) has been obtained; it is about 30-degrees-C lower than the commonly accepted value and it explains better the "memory effect" in the crystallization from the melt of this high performance polymer.

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High resolution transmission electron microscope (HREM) was used to observe the rigid chain polymer poly(aryl-ether-ketone) (PEK), so as to study the morphology of the crystals and molecular arrangement within a crystal.Many kinds of material crystal structures have been studied with HREM in recent years. So far as polymeric materials are concerned, the application of HREM

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A mild and highly efficient copper-catalyzed system for N-arylation of alkylamines with aryl iodides using binaphthol-based phosphoramidites as ligands was developed. The phosphoramidite ligands are stable, cost-effective and easily prepared from inexpensive, commercially available starting materials using a simple, efficient method. (c) 2005 Elsevier B.V. All rights reserved.

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A highly efficient palladium-catalyzed Suzuki coupling of aryl bromides with aiylboronic acids using phosphoramidite ligand 2c was developed. The phosphoramidite ligands are cost-effective and easily prepared from inexpensive, commercially available starting materials using a simple, efficient method. It represents an advance toward the discovery of low-cost catalyst systems for eventual availability. (c) 2005 Elsevier B.V. All rights reserved.

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渤海湾沿岸人口密集,工农、航运发达,渤海自身净化能力非常有限。因此,渤海湾 环境污染的压力越来越大,主要污染物包括重金属和持久性有机污染物的。四角蛤蜊广泛 分布于渤海湾海域,是一种重要的经济贝类,对污染物具有较强的富集能力。为了研究不 同站点渤海湾四角蛤蜊软体部重金属含量,选择大港油田、高沙岭码头、涧河村三个断面 进行研究,对不同站点四角蛤蜊软体部重金属含量进行了分析和讨论,最后对水生动物的 POPs 毒理调控通道进行了探索性研究,得到以下结果: 1. 通过比较渤海不同站点四角蛤蜊软体部重金属含量分布特征和方差分析,发现四 角蛤蜊软体部必需重金属元素含量较高,而非必需重金属元素含量较低,这是由于必需重 金属元素具有重要的生理功能作用。侧重比较A、B 两个断面各站位间四角蛤蜊软体部重 金属含量,发现虽然各站位间分布规律不明显,但各站位间差异显著。 2. 利用简单相关回归分析金属元素间及其与生物学性状间的关系,发现Mn 与Zn 之 间,Cu 与Zn 间均存在显著正相关,Se 与As、Cd 间存在显著正相关。另外,A 断面,BL 与Cd 含量显著负相关其回归方程为:Y(Cd)=-1395.97+88.34(BL);R=0.633;在B 断面,利用BW 和BH 分别与Cd 和As 显著负相关和显著正相关,其回归方程分别为:BW 和Cd 的回归方程为:Y(Cd)=-1968.80+220.72(BW);R=0.656。BH 和As 的回归方 程为:Y(As)=1496.86+227.82(BH);R=0.656。 3. 利用PLS(偏最小二乘分析)方法分析,发现五个生物学性状都与Co、As 呈正相 关,而与Cr、Pb、Se 呈负相关,而与必须重金属元素相关不明显。进一步分析表明表明 渤海湾海域中Co、As 含量低于四角蛤蜊正常生长发育的需要,而Cr、Pb、Se 的含量超过 四角蛤蜊正常生长发育所需的量。最后,通过PLS-DA 分析方法,发现C 站点样品能与A、 B 两个断面的站点区分开,而A、B 间未能区分开,反映了渤海湾三个断面的实际污染状 况。 4. 四角蛤蜊软体部重金属含量进行风险评价,首先,利用单因子污染指数法比较分析, 发现从1997 年-2008 年,渤海湾四角蛤蜊软体部Cd 的污染水平在不断降低,现在其含量 已低于《海洋生物质量标准》(第二类)标准。而Cr、As 有污染的趋势,需要引起重视。 然后,利用金属污染指数法进行比较研究,发现B 断面>A 断面>C 断面。最后,利用《人 体消费卫生标准》进行比较分析,发现Cd、Ni 存在轻度污染,因此需要加强其污染源的 控制。 5. 渤海湾污染物除了重金属外,还存在一些典型持久性有机污染物。为进一步揭示 二者间协同毒理机制,利用分子系统学方法,对芳香烃受体通道进行了探索性研究,发现 水生动物AhR通道基因在进化过程中发生了适应性进化,对进一步研究重金属和POPs对双 壳贝类的毒理机制具有参考价值。

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Vitellogenin (Vtg) is the precursor of yolk protein. Its expression and secretion are estrogen-regulated and are crucial for oocyte maturation. An in vitro xenoestrogen screening model was established by measuring Vtg induction in cultured primary hepatocytes from crucian carp. Vtg production was detected by biotin-avidin sandwich ELISA method while Vtg and cytochrome P4501A1 (CYP1A1) mRNA induction were measured by semi- quantitative PCR-primer dropping technique. Vtg and Vtg mRNA were dose-dependently induced by diethylstilbestrol (DES, 0.2-200 ng/mL) in hepatocytes of crucian carp. Co-treatment of the DES-induced hepatocytes with either 2,3,7,8-TCDD (TCDD, 0.1-4 pg/mL) or benzo[a]pyrene (B[a]P, 5-1000 ng/mL) resulted in a reduction of Vtg production and an increment of CYP1A1 mRNA expression both in a dose dependent manner, indicating the anti-estrogenic effects of the compounds. However, at lower tested concentrations, TCDD (0.1, 0.2 pg/mL), B[a]P (5 ng/mL) seemed to have a potentiating effect on Vtg expression and secretion, although by their own these compounds had no observable estrogenic effect on Vtg induction. Tamoxifen (a selective estrogen receptor modulators, 1 nmol/L-1 mumol/L), and P-naphtho-flavone (beta-NF, an aryl hydrocarbon receptor inducing compounds, 2.5-1000 ng/mL) also were employed to study the possible interactions in DES-induced Vtg expression. In co-treatment of the DES-induced hepatocytes with beta-NF or tamoxifen, the decrease in Vtg production did parallel induction of CYP1A1 for beta-NF, but tamoxifen inhibited Vtg induction did not parallel induced CYP1A1 expression in all test concentrations. On the contrary, it was found that in co-treatment of the TCDD-induced hepatocytes with DES, TCDD induced CYP1A1 mRNA production was inhibited by DES also. These results implicated a possible cross talk between estrogen receptor- and aryl hydrocarbon receptor-mediated pathways in the hepatocytes.

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Aryl hydrocarbon (Ah) receptor (Ah-agonist) effects of environmental samples containing polychlorinated aromatic hydrocarbons were evaluated using a 7-ethoxyresorufin-O-deethylase (FROD) assay of a primary hepatocyte culture from grass carp (Ctenopharyngodon idellus). The results were compared with those obtained from the assay using the rat hepatoma cell line H4IIE and chemical analysis using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). A dose-response relationship was observed between the EROD activities, either from primary hepatocyte culture assay or from H4IIE assay, and concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The results showed that the assay based on the H4IIE cell line (EC50 = 0.83 mug/mL) is more sensitive to TCDD than the assay based on primary hepatocyte Culture (EC50 = 9.7 pg/mL). In tests of environmental samples, the results from the assay using primary hepatocyte culture were comparable to those from the assay using the H4IIE cell line and chemical analysis of concentrations of mixtures of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/PCDF). The lack of a change in the activities of glutathione-S-transferase (GST) and lactate dehydrogenase (LDH) in cell culture upon exposure to TCDD indirectly indicates that the compound is persistent to biodegradation in the cell culture system. (C) 2004 Elsevier Inc. All rights reserved.

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联苯醚和芳基烷基醚类化合物是天然产物和聚合物材料中的重要的片段结构,研究其合成具有重要意义。近年来,过渡金属催化形成碳-氧键已成为制备联苯醚和芳基烷基醚类化合物的重要方法。钯体系虽然成功,但由于其属于贵金属,价格昂贵,而且反应所必须的有机膦配体,毒性较大,对环境危害较大,所以其应用受到了限制。 本论文通过利用空气稳定的Cu(bpy)2BF4 配合物,使得苯酚和烷基醇有效地进行偶合得到联苯醚产物。该方法可以在不使用昂贵弱碱Cs2CO3 的情况下,取得很好的产率,并且在较低的催化剂载入量的情况下,可以很好地适应各种官能团取代的底物。 本论文通过配体的扫描筛选,使得溴代苯和烷基醇的偶合反应得到了发展。更重要的是,使用该体系时分子间和分子内的碳-氧键都可以形成。通过该方法合成了一系列苯并环醚类化合物,这也是一价铜体系催化制备该类化合物的首次报道。

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聚芳醚酮是一种高性能热塑性材料,但其熔融温度高,熔体粘度大,流动性较差。液晶聚芳醚酮则具有非常丰富的液晶相织构和复杂的相转变行为,并且其熔体粘度低,流动性较好。将二者共混,液晶的加入势必降低聚芳醚酮的熔融粘度,改善其熔体流动性,另一方面液晶聚芳醚酮的液晶织构和相行为等势必受很大影响。因此开展这一研究工作不但有重要的理论意义,同时对改善这类材料的性能和拓宽其应用范围具有重要的实际意义。发现液晶聚芳醚酮/聚醚醚酮共混物的复杂相行为与组成密切相关。在以液晶聚芳醚酮为主的共混物中,高分子量的聚醚醚酮易于从低分子量的液晶聚芳醚酮基质相中分离出来,形成了特殊的环带结构。在50:50液晶聚芳醚酮/聚醚醚酮共混物中,两个组分在熔融状态下发生了液一液相分离,导致环带结构和聚醚醚酮球晶同时形成。在以聚醚醚酮为基质相的共混物中,低分子量的液晶聚芳醚酮很难从高分子量的聚醚醚酮基质相中分离出来,最后只能在聚醚醚酮球晶的边界形成单独的相区。当聚醚醚酮含量很高时,仅生成聚醚醚酮球晶。首次在液晶聚芳醚酮与聚醚醚酮共混物中发现了环带球晶,并利用溶剂选择性蚀刻的方法确定了其相结构和组成。环带球晶中的亮心和亮环是液晶聚芳醚酮相,其c轴(分子链方向)垂直于膜平面,而。和b轴则在膜平面内没有固定的取向。暗环则是聚醚醚酮与部分液晶聚芳醚酮的共存相,其中液晶聚芳醚酮晶体的分子链也垂直于膜平面,但聚醚醚酮片晶则呈现复杂的结晶取向。确定环带球晶的形成机理,从分子水平上提出环带球晶的生长模型,即间歇式增长过程,符合结构不连续模型。总结了环带球晶的形成规律和必要条件为:(l)液晶聚芳醚酮为主要成分;(2)液晶聚芳醚酮与聚醚醚酮有一定相容性,至少在熔融态分子相容;(3)液晶聚芳醚酮的各向同性相向液晶相的转变温度要高于聚芳醚酮的结晶温度;(4)液晶聚芳醚酮相转变(或结晶)速率与共混物的相分离速率相匹配或前者略大于后者;(5)降温速率或等温结晶温度适当。聚醚醚酮/含氟液晶聚芳醚酮共混物在熔体状态下的流动行为与共混物的组成、两相的相容性及相的转变有着密切的关系。在聚醚醚酮/含氟液晶聚芳醚酮共混物中,当前者为主要成份时,流动曲线形状与纯PEEK的相似,而当后者为主要成份时,表现出与含氟液晶聚芳醚酮相似的流变行为。共混物的复数粘度、储存模量和损失模量总体来说随F一队EK含量的增加而逐渐下降,只有当含氟液晶聚芳醚酮含量为50%时,共混物的复数粘度、储存模量和损失模量出现了局部极大值。