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1.
3,4-二苯基-2,5-二(3,5-二溴苯基)环戊二烯酮与二苯乙炔经Diels-Alder环加成反应制得1,2,4,5-四苯基-3,6-二(3,5-二溴苯基)苯(6);6经Suzuki偶联反应制得1,2,4,5-四苯基-3,6-二[3,5-二(4-十二烷基苯基)]苯基苯(8);8经路易斯酸催化的Scholl氧化脱氢关环反应合成了一个新的扶手型分子石墨烯,其结构经1H NMR,13C NMR和MALDI-TOF-MS表征。  相似文献   

2.
以3,6-二溴-2,7-二羟基萘为起始原料,与硫酸二甲酯经甲醚化反应得3,6-二溴-2,7-二甲氧基萘(2);2与苯酚在碘化亚铜催化下经取代反应合成了新化合物——2,7-二甲氧基-3,6-二苯氧基萘,总收率82.5%,其结构经1H NMR,13C NMR,ESI-MS和元素分析表征。  相似文献   

3.
本文用3,4-二苯基-2,5-二(3,5-二溴苯基)环戊二烯酮(4a)与二苯乙炔(5a)通过Diels-Alder环加成反应得到1,2,4,5-四苯基-3,6-二(3,5-二溴苯基)苯(6a)。化合物6a通过经典的Suzuki偶联反应得到1,2,4,5-四苯基-3,6-二(3,5-二(4-十二烷基噻吩))苯基苯(8a),再利用Fe Cl3作为氧化剂发生Scholl氧化脱氢关环反应,得到目标化合物1a。采用类似合成方法,得到目标化合物1b。化合物的结构均通过1H NMR和MALDI-TOF MS表征,并对其光谱特征、热性能及电学性能进行了初步研究。  相似文献   

4.
杨圣伟  陈熙  李振卿  敖桂珍  候丙波 《合成化学》2011,19(5):619-621,625
以莽草酸为起始原料,经酯化、丙酮叉保护顺式邻二羟基、叔丁基二甲硅烷保护羟基、还原、羟基酯化、脱保护基、保护反式邻二羟基、烯丙醇氧化,脱保护基共9步反应,合成了新型(5R,6S)-3-苯甲酰氧基亚甲基-5,6-二羟基-2-环己烯-1-酮,总产率19.3%,其结构经1H NMR,IR和HR-MS表征.  相似文献   

5.
2-氨基-3,6-二甲氧基苯甲醛与1,2-环己二酮发生Friedlander缩合反应合成了新化合物5,8,5',8'-二甲氧基-3,3'-二亚甲基-2,2'-双喹啉,其结构经UV,1H NMR,IR和MS表征.  相似文献   

6.
2-氨基-3,6-二甲氧基苯甲醛与1,2-环己二酮发生Fried lander缩合反应合成了新化合物5,8,5,′8′-二甲氧基-3,3′-二亚甲基-2,2′-双喹啉,其结构经UV,1H NMR,IR和MS表征。  相似文献   

7.
以5-溴水杨醛、1,2-二溴乙烷、邻苯二胺和壳聚糖为原料,采用超声波催化法合成了壳聚糖嫁接大环席夫碱,其结构经1H NMR,FT-IR,MS和元素分析确证。  相似文献   

8.
以重氮丙酮酸乙酯和氨基醇为原料,经过氨解合成了一系列β-重氮-α-羰基酰胺类化合物,并与环己烯反应制备了环丙烷化产物,其结构经1H NMR,13C NMR,IR和HR-MS确证。  相似文献   

9.
以3-硝基邻苯二甲酸为原料,经脱水成酐、氨解、还原酰化、硝化、水解、还原等六步反应合成了一种新型的环芳酰胺的构筑单元对苯二胺衍生物——3,6-二氨基-N-异丁基邻苯二甲酰亚胺,总收率16.4%,其结构经1H NMR,13C NMR和ESI-MS表征.  相似文献   

10.
对8-羟基异香豆素的合成方法进行研究.以麦氏酸为原料,通过傅克酰基化,羰基保护,酯基还原,脱保护,得到关键中间体3-乙炔基-2-(羟甲基)环己-2-烯-1-酮,再经酸性环化加成,环己烯酮环的芳构化,2,3-二氯-5,6-二氰对苯醌(DDQ)氧化等步骤,合成得到8-羟基异香豆素.合成的化合物结构经过~1H NMR, ~(13)C NMR, IR, HRMS表征.  相似文献   

11.
Summary Sonic spray ionization (SSI) was compared with atmospheric pressure chemical ionization (APCI) as an interface for liquid chromatography (LC)-mass spectrometry (MS) for the analysis of some local anesthetics. Peaks at [M+H]+ constituted the base peaks for all compounds by both SSI and APCI, except for prilocaine. The sensitivities by SSI for tetracaine, benzoxinate, dibucaine, bupivacaine and mepivacaine were 4–16 times higher than those by APCI; those by SSI for procaine and lidocaine were equivalent to those by APCI. Only for prilocaine was the sensitivity by SSI two times lower than that by APCI. In view of the higher sensitivities obtained for many local anesthetics by SSI, we established a detailed procedure for the assay of these drugs in human plasma and urine by LC-MS with SSI in combination with a diol-bonded silica gel HPLC column that enabled direct injection of crude biological samples without complicated pretreatment. The recoveries, sensitivities, accuracies and precisions were found satisfactory to quantitate them at their therapeutic levels.  相似文献   

12.
The interest in the low energy self-emulsification techniques has exploded in the recent years, driven by three main trends: by the transition to “greener” technologies in both its aspects—less energy consumption and replacement of the petrochemicals by natural ingredients; by the costly and maintenance demanding equipment for nanoemulsification; and by the quest for efficient and robust self-emulsifying formulations for oral drug delivery. Here, we first present a brief overview of the main known low-energy methods for nanoemulsion formation, focusing on their mechanistic understanding and discussing some recent advances in their development and applications. Next, we review three conceptually new approaches for self-emulsification in chemical technologies, discovered in the last several years. The colloidal features and the specific requirements of the self-emulsifying drug-delivery systems (SEDDS) are also discussed briefly. Finally, we summarize the current trends and the main challenges in this vivid research area.  相似文献   

13.
研究了镍锍试金预富集中子活化分析测定岩石样品中的铂族元素。纯化捕集剂氧化镍,大大降低了化学分离全流程铂族元素的空白。取样量为50g时,所需溶剂各元素的空白值为(ng/g):Pt<0.05、Pd<0.05、Os<0.01、Ru<0.05、Rh<0.05、Ir=0.002。用平面锗探测器测定Rh使测定下限降低了两个数量级,对几种国标地球化学标准物质的测定结果与推荐值基本符合。  相似文献   

14.
Summary Program temperature retention indices for fifteen nonalkane solutes have been determined by cubic splines, by other procedures found in the literature and by interpolation of the n-alkanes retention time logarithm for eleven temperature programs. A comparison in terms of variance of the differences between PTRI calculated by CS and each of the remaining methods is made for each of the eleven program runs, for each of the three stationary phases used and for many of the programs. The smallest variances obtained result when the Zenkevich, van den Dool & Kratz and Chen et al. methods are tested. The stationary phase polarity is of no relevance since it has no effect on the specific PTRI found by the different methods employed in this work.  相似文献   

15.
Effects induced by chemical and structural inhomogeneities on the electronic transport in organic crystals with the focus on highly-ordered polyacenes are discussed in this paper. The material class chosen is of great importance as polyacenes are widely studied with perspectives on applications in thin film devices. As will be shown, the charge carrier mobility in these long-range ordered molecular systems is limited by chemical impurities rather than by structural inhomogeneities. Time-of-flight spectroscopy on polyacenes purified by zone-refinement does not only show coherent carrier movement for holes but also for electrons, which is rarely observed for compounds that can be purified by sublimation only. Finally, we will present a direct comparison between the chemical species and their amount on the surface and in the volume of tetracene crystals. The significantly higher impurity concentration at the surfaces is relevant for the mobility estimated by field-effect transistor (FET) studies on single crystals in planar-geometry.  相似文献   

16.
The changes in the vibrational frequencies of 1-tert-butyl and 1,2-di-tert-butyl derivatives of 3,3-dimethylcyclopropene brought about by substitution of the central carbon atom (X) of the tert-butyl moieties by Si, Ge, Sn, or Pb atoms are examined. The most important decrease in the vibrational frequencies implicating the X(CH(3))(3) moieties is noted for substitution of X=C by Si. The substitutions of Si by Ge or Ge by Sn or Sn by Pb are not accompanied by the pronounced frequency shifts observed for the C-->Si transition. An explanation is given for trends in these vibrational frequencies for the transitions X=C-->Si-->Ge-->Sn-->Pb. It is concluded that there are lower limiting values of the vibrational frequencies of a molecular moiety which are approached when the mass of its isovalent atom is increased. This leads to the formation of cluster regions in the vibrational spectra for the frequencies of the SnC(3) and PbC(3) moieties.  相似文献   

17.
包埋法固定化酶过程中,酶固定化载体的选择和设计是酶固定化过程的关键因素,适宜的载体微环境对酶活性和稳定性的影响尤为重要。论文首先分析并提出了影响固定化酶所处载体微环境的主要因素,包括载体的亲疏水性、结构形态和反应活性。载体的亲疏水性决定固定化酶微环境中的水分含量。载体的结构形态对酶形成的笼效应,以及载体的反应活性,包括共价键合、静电和氢键等的结合能力,影响酶构象的稳定性和运动性。另外,底物/产物的扩散速率和酶的可及性也同样受到载体的孔结构、孔分布以及载体反应活性的影响。本文介绍了常用的酶包埋载体,包括sol-gel二氧化硅、高分子水凝胶以及高分子-二氧化硅杂化凝胶固定化酶过程,结合上述影响酶微环境的因素,分析比较了三类载体固定化酶的包埋率、活性和稳定性,综述了为改善固定化酶微环境所进行改进研究的进展。  相似文献   

18.
邵敏  陈永亨  李晓宇 《分析化学》2012,40(8):1139-1146
建立了人体血清中多种环境雌激素:多溴联苯醚、邻苯二甲酸酯和双酚A的快速可靠的连续在线分离及在气相色谱-质谱上的分析方法.血清样品经过浓盐酸使蛋白质变性,用乙醚萃取,经硅胶柱分离出多个族组分:多溴联苯醚(Polybrominated diphenyl ethers,PBDEs)、邻苯二甲酸酯(Phthalate estcrs,PAEs)和双酚A(Bisphenol A,BPA),最后由气相色谱-质谱的选择离子检测测定.PBDEs,PAEs和BPA标准曲线回归方程拟合度R2均大于0.99,表明在测试的浓度范围内线性关系良好.PBDEs目标化合物的检出限为0.005~0.048μg/L,PAEs目标化合物的检出限为0.103~0.833μg/L,BPA的检出限是0.035 μg/L.标准样品重复样中,PBDEs的RSD(relative standard deviation)值分别为2.8%~10.9%;PAEs的RSD值为5.6%~9.9%;BPA的RSD值为3.0%.实际血清样品中,PBDEs的加标回收物PCB209(Polychloride diphenyl ether 209)的回收率范围是74.8%~88.5%;PAEs中的加标回收物DBP-D4(Dibutyl phthalateDeutorium 4)的回收率范围为78.7%~97.0%;BPA中的加标回收物BPA-D16( Bisphenol A-Deutorium 16)的回收率范围是76.3%~93.1%.本方法检测血液中多种环境雌激素灵敏度高、重现性和回收率均良好.  相似文献   

19.
Summary: This minireview describes strategies for preparation of biodegradable (from polylactides, and poly(ε-caprolactone) and from their derivatives) nano- and microspheres for medical applications, in particular for drug delivery. In addition to standard methods of particles' formation by emulsification of polymer solution in water-miscible organic solvent with subsequent solvent evaporation or extraction there are described methods of particles formation by self assembly of polymer macromolecules, by dialysis of polymer solutions in organic water-miscible solvents carried on against water and by dispersion ring-opening polymerization of heterocyclic monomers. Strategies for encapsulation of bioactive compounds into nano- and microspheres are presented.  相似文献   

20.
应用X荧光光谱仪结合压片法制样快速测定铜冶炼中炉前的炉渣和冰铜中的铜、铁、二氧化硅、氧化钙及冰铜中各组分的分析。利用手工分析制备质控样品作为标准物质绘制工作曲线,解决了炉前样品没有标准样品的问题。对炉前分析样品基体不稳定带来的背景干扰,采用手工分析对照,不断调整工作曲线进行对照校正,通过质控管理能够满足生产指标控制的要求。分析结果表明,方法的相对标准偏差(RSD)为0.01%~0.28%,测定结果与通用的容量法分析结果对比,结果基本一致。  相似文献   

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