香茅基芳基醚类保幼激素类似物的简便合成方法

许多香叶基芳基醚和香茅基芳基醚已证明是有效的昆虫保幼激素^[1-3].以往合成此类化合物,只能在酚与较活泼的香叶基溴的反应中使用KOH(或NaOH),与较不活泼的香茅基溴的反应则仍沿用Williamson法.我们曾报导了以聚氧乙烯类表面活性剂代替冠醚作为相转移催化剂合成醚类化合物的方法^[4].     

三相催化合成苄醚和芳醚

芳香族混醚的经典合成,通常用Williamson法,该法反应条件比较苛刻,某些醚类的产率较低。本文是用季铵盐类相转移催化剂连接到二乙烯基苯交联聚苯乙烯上,形成了不溶性的固体高分子相转移催化剂,以相转移催化的机制,用于加速水-有机两相体系的反应,三相催化成功地合成了五种苄醚和芳醚。     

聚乙二醇相转移催化作用下Darzens酯缩合

环氧酸酯缩合作用通常在无水条件下进行^[1],不能在应用氢氧化钠水溶液的相转移催化条件下进行。因为卤代酸酯在此情况下发生水解。M.Makosza在无水碳酸钾和18-冠醚-6的两相体系中合成了2-苯基环氧酸乙酯,b.p.99-109℃/0.5mmHg产率72%^[2]。     

聚苯乙烯负载季鏻盐型树脂的制备及催化效应

用高分子材料负载季鏻盐相转移催化剂的开发和研究已有报导^[1,2]。Reeves^[3]和Idoux^[4]曾用氯甲基聚苯乙烯树脂经多步反应制得催化剂。Tomoi通过CF₃SO₃H催化ω-溴代烯烃与树脂付-克烷基化反应制得溴烃基树脂,再与三烃基膦反应制成高分子负载季磷盐催化剂, 具有良好的相转移催化效应。     

断裂醚键的一种新试剂系统

Kollonitsch^[1]曾报道乙硼氢与四氢呋喃在Carius管中60℃加热64小时,生成硼酸丁酯,产率61%;若反应在室温下进行,需16周才能完成。继后,Past^[2]将φSBH₂与醚R'OR"反应,获得φSR'和H₂BOR"。Freeguard等^[3,4]将乙硼氢,戊硼氢-9或钠硼氢和卤素(Cl₂、Br₂、I₂、ICl)与醚类或醇类在常温下反应,醚键很快发生断裂,生成相应的卤化物和硼酸酯,产率达80%以上;二苯醚与具有β-卤素取代基的醇则不能顺利反应。     

二(甲基环戊二烯基)二氯化钛及某些取代苯氧基衍生物的合成

二(甲基环戊二烯基)二氯化钛[(MeCp)₂TiCl₂](Ⅰ),Wilkinson等人^[1]曾用四氯化钛和甲基环戊二烯基钠反应来制备,产率26％.后来Brantly^[2]用四氯化钛和MeC₅H₄MgCl在乙醚-苯混合溶液中于-70℃反应.以上两种方法不但操作复杂,且条件苛刻,产率低.最近吴绍祖等^[3]用二乙胺作为氯化氢的接受体,四氢呋喃作溶剂,由TiCl₄和甲基环戊二烯直接反应来合成.产率43％.我们采用甲基环戊二烯基锂与TiCl₄反应来合成,产率为63％.     

磷酸氢二钾催化多组分一锅法反应合成1,4-二氢吡喃并[2,3-c]吡唑衍生物

绿色、简便、高效的催化四组分反应合成吡喃并[2,3-c]吡唑类杂环化合物是当今有机化学领域的研究热点。 本文发展了在水与聚乙二醇(PEG-200)的混合液中,廉价易得的磷酸氢二钾(K₂HPO₄·3H₂O)催化乙酰乙酸乙酯、水合肼、芳香醛和丙二腈的多组分“一锅法”反应,合成一系列1,4-二氢吡喃并[2,3-c]吡唑-5-腈衍生物,产率为88%~98%。 该方法避免了使用复杂昂贵的催化剂和繁琐的纯化过程。     

新型杯[6]芳烃活化KOH催化合成(Z)-1,2-二芳硒基烯

以对叔丁基苯酚为原料，经一步法制得对叔丁基杯[6]芳烃。通过逆傅克反应、亲核取代反应制得二烷基化杯[6]芳烃。最后通过磺化、亲核取代等反应，合成了下缘含喹啉基长链的新型夹状醚杯[6]芳烃化合物（2a~2c），其结构经¹H NMR, ¹³C NMR和HR-MS(ESI-QTOF)表征。以10.0 mol%杯[6]芳烃化合物（2b)为相转移催化剂，20.0 mol%KOH为催化剂，THF为溶剂，较高产率和高选择性地合成了一系列(Z)-1,2-二芳硒基烯化合物，其结构经¹H NMR和NOESY确证。2b重复使用6次，催化活性无明显降低。     

理论研究“受阻路易斯酸碱对”催化的烯醇硅醚氢化反应机理

“受阻路易斯酸碱对”(FLPs)催化的烯醇硅醚氢化反应是一类重要的直接合成醇类化合物的方法, 然而目前其反应机理仍不明确. 基于此, 以乙基取代的全氟苯基硼作为路易斯酸(Et-B(C₆F₅)₂), 三叔丁基膦(t-Bu₃P)作为路易斯碱, 烯醇硅醚化的苯乙酮(Me-TMS)作为底物建立了模型反应, 并使用密度泛函理论系统研究了其催化氢化反应机理. 结果显示: FLPs催化的烯醇硅醚氢化反应从Et-B(C₆F₅)₂和t-Bu₃P形成B-P-FLPs开始, 随后会依次经过H₂裂解, H⁺和H^-转移等过程, 其中H⁺转移为决速步, H^-转移无势垒, B-P-FLPs生成及H⁺转移是吸热反应. 升高温度不利于氢化反应发生, 但是增大压力可促进反应进行. 底物取代基效应会影响H^-转移过程, 可能使反应不发生.     

含氮杂环聚芳醚酮三元共聚物的性能

聚芳醚酮是一种新型热塑性耐高温高分子材料,具有优异的力学性能、电性能、抗辐射性能等,特别适合作高性能复合材料的基质及超级工程塑料,关于聚芳醚酮已有多篇文章报道,而基于C-N偶合反应合成的聚芳醚酮报道甚少^[1],我们曾报道含氮杂环聚醚酮酮PPEKK的合成^[2].本文以1,4-二(4-氯代苯甲酰基)苯,4,4′-二氟二苯酮及4-(4-羟基苯基)-2,3-二氮杂 萘-1-酮为原料,合成了主链中含有C—N键的新型含氮杂环聚芳醚酮三元共聚物 (PPEKEKK),对共聚物的结构和性能进行了表征.     

128例脑性瘫痪血钙、锌、铁、铜、镁元素分析

为探讨小儿脑性瘫痪(CP)体内微量元素的变化,测定了128例脑性瘫痪患者血钙、锌、铁、铜、镁含量,随机选择128例正常儿童进行对照分析。结果表明,两组病例血锌、铜、镁均在正常范围,脑瘫组血钙56例、铁45例低于正常参考值,健康组血钙16例、铁11例低于正常参考值。经统计学处理,两组病例中血钙、铁、铜、镁含量具有显著性差异(P<0.05),血锌无显著性差异(P>0.05)。提示脑瘫儿童血钙、铁、铜、镁含量均低于正常儿童,补充钙、铁、镁等可能有利于脑瘫康复。     

High-performance liquid chromatography of alkaloids

Literature information on the HPLC of alkaloids, including adsorption, reversed-phase, ion-exchange, ion-pair, and other variants is generalized. Results are given of the chromatographic analysis of various classes of alkaloids with an indication of the conditions of separation, and the columns used, and also of the methods of detection. The advantages and disadvantages of the HPLC variants are discussed. The review includes the literature over the last 14 years. Scientific Center for Chromatography, Institute of Chemistry and Physics of Polymers, Uzbek Academy of Sciences, Tashkent. Institute of the Chemistry of Plant Substances, Uzbek Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 595–613, September–October, 1991.     

Cathode of a hydrogen-oxygen fuel cell with a solid polymer electrolyte: The effect of the flooding of pores by water on the characteristics of the active layer

A computer model of the active layer of the cathode of a hydrogen-oxygen fuel cell with a solid polymer electrolyte is studied. The active mass of the electrode consists of equidimensional grains of the substrate (agglomerates of carbon particles with platinum particles embedded in them) and a solid polymer electrolyte (Nafion). The flooding by water can be experienced by both the pores in the substrate grains, which facilitate the oxygen penetration into the active layer of the electrode, and the voids between the grains. All possible versions of the flooding of these pores by water are considered. A calculation of the optimum, at a given polarization of the electrode, value of electrochemical activity, the thickness of the active layer, and the weight of platinum is performed. The major parameters of the system are the concentrations of grains of the substrate and solid polymer electrolyte, the size of these grains, the platinum concentration in the substrate grains, the average diameter of pores in the substrate grains, and the polarization of electrodes. The ultimate aim of the work is to estimate how the flooding of pores of the active layer of the cathode by water affects the magnitude of the optimum current, the effective thickness of the active layer, and the weight of platinum.Translated from Elektrokhimiya, Vol. 41, No. 1, 2005, pp. 35–47.Original Russian Text Copyright © 2005 by Chirkov, Rostokin.     

The retention of 1,1-dimethylhydrazine and its decomposition products on alkyl-grafted silica gels under the ion pair chromatography conditions

The influence of eluent composition (the nature and concentration of the ion-pair reagent, medium pH, the concentration of the buffer solution, and the content of acetonitrile) on the retention of asymmetric dimethylhydrazine and its decomposition products on hydrophobized silica gels under the ion pair chromatography conditions was studied. It was shown that, for these sorbates, the influence of ion-pair reagents can be described correctly in terms of stoichiometric models. Empirical dependences of the retention of the components studied on the concentration of the buffer solution and the volume concentration of acetonitrile were determined. Conditions for the separation of the components were suggested. Original Russian Text ? A.D. Smolenkov, S.A. Ponomarenko, O.A. Shpigun, 2009, published in Zhurnal Fizicheskoi Khimii, 2009, Vol. 83, No. 3, pp. 565–574.     

Lipopolysaccharides of the pseudotuberculosis microbe Yersinia pseudotuberculosis

This review generalizes the results of structural investigations of the polysaccharides of the O-specific side chains, of the core oligosaccharides, and of the lipid A of the pseudotuberculosis microbeYersinia pseudotuberculosis which causes Far-Eastern scarlatina-like fever. The complete structures of the repeating units of the specific polysaccharides from the lipopolysaccharides of serovars I A, I B, III, IV A, V A, V B, and VI which are responsible for the O-antigenic specificity of the microorganism are given. For the majority of serovars the repeating unit is represented by a branched pentasaccharide. Exceptions are the lipopolysaccharides of serovars I A and III which have a tetrasaccharide repeating unit. The presence of an aminosugar residue at the reducing end, by which the O-specific chain is attached to the oligosaccharide of the core, is common and characteristic for the lipopolysaccharides isolated from all the serovars. The structures of the core oligosaccharide and of lipid A, which are common for all serovars ofYersinia pseudotuberculosis, are given.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, USSR Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 163–171, March–April, 1988.     

Electrokinetic investigation of surfactant adsorption

Fuerstenau [D.W. Fuerstenau, in: M.L. Hair (Ed.), Dekker, New York, 1971, p. 143] has already discussed the role of hydrocarbon chain of surfactants, the effect of alkyl chain length, chain structure and the pH of the solution on the adsorption process of surfactants. Later Kosmulski [M. Kosmulski, Chemical Properties of Material Surfaces, Surfactant Science Series, vol. 102, Dekker, New York, Basel, 2001] included the effect of surfactant concentration, equilibration time, temperature and electrolyte in his approaches. Certainly, the character of the head groups of the surfactant and the properties of the adsorbent surface are the basis for the adsorption process. Different surfactants and adsorbents cause different adsorption mechanisms described firstly by Rosen [M.J. Rosen, Surfactants and Interfacial Phenomena, second ed., Wiley, New York, 1989]. These adsorption mechanisms and their influencing factors were studied by electrokinetic investigations. Here only changes of the charges at the surfaces could be detected. To control the results of electrokinetic investigations they were compared with results from ellipsometric measurements. In the case of surfactant adsorption the chain length was vitally important. It could be shown by the adsorption of alkyl trimethyl ammonium bromides onto polymer films spin coated at wafer surfaces. The influence of the chain length depending on surface properties of the polymer film was studied. Streaming potential measurements were applied for these investigations. The obtained results enabled us to calculate the molar cohesive free energy per mol of CH2-group in the alkaline chain of the surfactant if all other specific adsorption effects were neglected.     

Adsorption of fatty acids from solutions in organic solvents on the surface of finely dispersed magnetite: 1. Isotherms of adsorption of oleic,linoleic, and linolenic acid from carbon tetrachloride and hexane

Isotherms of adsorption of oleic, linoleic, and linolenic acids on magnetite from solutions in carbon tetrachloride and hexane are measured. When CCl₄ is used as a solvent, the adsorption values increase in the following order: oleic, linoleic, and linolenic acid. In the case of hexane, the order is opposite. Adsorption isotherms of the fatty acids on aggregated magnetite are described in terms of the theory of volume filling of micropores. It is disclosed that, in the case of CCl₄ , the limiting adsorption values and characteristic energies of the process increase in a series: oleic, linoleic, and linolenic acid, but in the case of hexane, they decrease in the same sequence. Upon the adsorption of fatty acids from solutions in CCl₄ and hexane on finely dispersed magnetite, molecules of the acids and solvents compete for the active sites on the adsorbent surface. The number of double bonds in the molecules of unsaturated fatty acids and the desolvation of both the adsorbent surface and adsorbate molecules substantially affect the adsorption of these acids. The effect of the solvents is most pronounced for the adsorption of oleic acid, decreasing with a rise in the number of double bonds in a fatty acid molecule.Translated from Kolloidnyi Zhurnal, Vol. 66, No. 6, 2004, pp. 779–783.Original Russian Text Copyright © 2004 by Korolev, Ramazanova, Yashkova, Balmasova, Blinov.     

Preparation of high-quality colloidal mask for nanosphere lithography by a combination of air/water interface self-assembly and solvent vapor annealing

Nanosphere lithography (NSL) has been regarded as an inexpensive, inherently parallel, high-throughput, materials-general approach to the fabrication of nanoparticle arrays. However, the order of the resulting nanoparticle array is essentially dependent on the quality of the colloidal monolayer mask. Furthermore, the lateral feature size of the nanoparticles created using NSL is coupled with the diameter of the colloidal spheres, which makes it inconvenient for studying the size-dependent properties of nanoparticles. In this work, we demonstrate a facile approach to the fabrication of a large-area, transferrable, high-quality latex colloidal mask for nanosphere lithography. The approach is based on a combination of the air/water interface self-assembly method and the solvent-vapor-annealing technique. It enables the fabrication of colloidal masks with a higher crystalline integrity compared to those produced by other strategies. By manipulating the diameter of the colloidal spheres and precisely tuning the solvent-vapor-annealing process, flexible control of the size, shape, and spacing of the interstice in a colloidal mask can be realized, which may facilitate the broad use of NSL in studying the size-, shape-, and period-dependent optical, magnetic, electronic, and catalytic properties of nanomaterials.     

Effect of Cr(VI) anions on adsorption and desorption behavior of Cu(II) in the colloidal systems of two authentic variable charge soils

Heavy metals in wastes exist as multiple pollutants. The study of the interactions between multiple pollutants and soils should be of significance in practice. In the present study, the effect of chromate on adsorption and desorption behavior of Cu(II) in two variable charge soils was investigated, with the emphasis on the adsorption and desorption equilibria of Cu(II). The results showed that chromate can affect adsorption and desorption of Cu(II) in the colloidal systems of two variable charge soils. The extent of the effect was related to the initial concentrations of chromate and Cu(II), the system pH, and the nature of the soils. The presence of chromate led to an increase in the adsorption of Cu(II). For example, in the presence of 0.5, 0.8, 1.0, and 1.5 mmol L(-1) of chromate, for the rhodic ferralsol the adsorption of Cu(II) increased by 15.3, 18.0, 19.0, and 20.2%, respectively. For the hyperrhodic ferrasol, the corresponding figures were 11.9, 17.0, 20.3, and 26.1%, respectively. The presence of chromate also caused an increase in the desorption of Cu(II). For instance, in the presence of 0.5, 1.0, and 1.5 mmol L(-1) of chromate, the desorption for the rhodic ferralsol increased by 16.9, 27.5, and 34.1%, respectively. For the hyperrhodic ferralsol, the corresponding figures were 18.1, 35.6, and 51.4%, respectively. The increments of the adsorption and desorption increased with the increase in equilibrium concentration of Cu(II) in the solution. For instance, when the equilibrium concentrations were 0.5, 1.0, 1.5, and 2.0 mmol L(-1), the increments for the rhodic ferralsol were 2.5, 3.2, 3.3, and 3.0 mmol kg(-1), respectively. For the hyperrhodic ferralsol, the corresponding figures were 2.9, 3.5, 4.0, and 4.2 mmol kg(-1), respectively. The effect of chromate for the hyperrhodic ferralsol was greater than that for the rhodic ferralsol. This is caused by the difference in the content of iron oxides for the two soils. The increments of the adsorption and the desorption of Cu(II) increased with the rise in pH, reaching a maximum value, and then decreased. It can be assumed that the increment of the adsorption was caused by the change in surface charge of the soils induced by the adsorption of chromate and the cooperative adsorption of chromate adsorbed and Cu(II). The increase of electrostatically adsorbed Cu(II) was responsible for the increase in the desorption of Cu(II).     

Metal chelates of phosphonate-containing ligands: VII. Analytical applications of 1-hydroxyethane-1,1-diphosphonic acid

The polarographic behavior of copper, lead, antimony, and zinc ions in the presence of the title ligand, HEDP, is discussed. In highly alkaline solutions, the reversible wave of copper splits into two components, reversible and irreversible, the first of which is attributed to the reduction of the free cupric ions and the second wave was assigned to the reduction of the copper phosphonate species. The polarograms of zinc and antimony showed the presence of a single irreversible wave. In the case of lead, a quasi-reversible wave is observed. Cobalt and nickel forms inactive phosphonate chelates as inferred from the suppression of the wave heights with increasing of both the concentration of the ligand and the pH of the medium. In the presence of sufficiently excess HEDP buffered to pH 11.8, mixtures of the six elements showed the presence of four reasonably separated waves at half-wave potential values ?0.51, ?0.83, ?1.17, and ?1.55 V vs SCE corresponding to the reductions of copper, lead, antimony, and zinc complexes, respectively. The possibility of the individual and simultaneous analysis of these elements in their ternary mixtures with cobalt and nickel is discussed.