大环二萜类化合物的研究(Ⅳ)——Isosarcophytol—A前体化合物的合成

Isosarcophytol-A(1)是1982年首次从澳大利亚软珊瑚(Nephthea brassica)中分离鉴定的西松烷型(Cembrane)大环二萜类化合物,其结构为6,10,14-三甲基-3-异丙基-3E,5E,9E,13E-环十四碳四烯-1-醇,是Sarcophytol—A(2)的异构体,但有关1的生物活性试验和全合成研究尚未见报道.我们在前文报道了以低价钛诱导的分子内二羰基偶联为环化方法,完成了天然大环二萜类化合物Cembrene—C的全合成和Sarcophytol—A(2)苄醚衍生物(3)的合成.本文报道以天然法呢醇4为起始原料,经区域选择性氧化、羟醛缩合等六步反应,合成了1的前体化合物11.合成路线如下:     

PEG-PLA嵌段共聚物的合成及~(13)C NMR对平均链段长度的测定

本文报道聚乙二醇(PEG)在辛酸亚锡存在下与丙交酯(LA)反应合成PEG-PLA嵌段共聚物,用~(13)C NMR测定了共聚物的结构,估算了平均链段长度.实验结果表明,L_(PEG)在反应过程中保持不变,而L_(PLA)随反应时间和LA在原料配比中含量的增加而增加,呈逐步聚合反应特点.对聚合反应机理作了推测.     

非晶态合金催化剂用于二甲基紫脲酸加氢反应

二甲基紫脲酸加氢反应;nicob/白炭黑催化剂;非晶态合金催化剂     

Synthesis of polypiperazine-amide thin-film membrane on PPESK hollow fiber UF membrane

A new interfacial polymerization (IP) procedure is developed in order to synthesize polypiperazine-amide thin-film membrane on the inner surface of poly(phthalazinone ether sulfone ketone) (PPESK) hollow fiber ultrafiltration (UF) membrane.A hollow fiber composite membrane with good performance was prepared and studied by FT-IR and scanning electron microscopy.     

Darstellung und Kristallstruktur von TICu[CuO2]

Investigations on Electronically Conducting Oxide Systems. XVI. Solid Solutions and Conductivity in the System MgTi₂O₅? Ti₃O₅ Solid solution formation is reported for the system Mg_1–xTi_2–x^IVTi_2x^IIIO₅. With increasing x there is at room temperature a transition from the orthorhombic pseudobrookite structure to the monoclinic low-temperature modification of Ti₃O₅. The X-ray diffraction pattern results are supported by DSC measurements, electrical and magnetic investigations. The tendency of Ti? Ti pair formation in the low-temperature Ti₃O₅ structure is accompanied by a drop of the activation energy for electrical conductivity and a decreasing susceptibility at high Ti^III concentrations.     

温度及pH敏感的树枝状高分子衍生物合成及药物控制释放研究

对合成的系列聚酰胺-胺型(PAMAM)树枝状高分子进行端基的羟基化和氯乙酰化两步修饰,使PAMAM最外层接上烷基氯.以修饰产物为引发剂,通过原子转移自由基引发甲基丙烯酸N,N-二甲氨基乙酯(DMAEMA)聚合得到树枝状PAMAM高分子衍生物,并对其结构用FTIR、1H-NMR和粒径分析进行了表征.紫外可见分光光度仪测定证实此高分子具有温度及pH敏感性.通过对小分子药物控制释放研究表明,此树枝状高分子衍生物通过环境pH值可有效地控制小分子药物的释放.     

Thermal and structure analysis of FeSO4·H2O-BaO2 mixtures

Investigations on the thermal decomposition of FeSO₄·H₂O-BaO₂ mixtures were carried out under isothermal conditions by using simultaneously solid electrolyte cell (EMF-method). Evoked interactions producing oxygen in the temperature range 553-673 K were established by means of a solid electrolyte oxygen analyzer. Based on Mössbauer spectroscopy data and X-ray analysis it was proved that these reactions were associated with the release of oxygen from barium peroxide, oxidation of ferrosulphate-monohydrate to FeOHSO₄, and formation of barium ferrites such as BaFe₂O₄ and BaFe₁₂O₁₉.     

刚果红与血清白蛋白相互作用的极谱分析

在pH4．7HAc-NaAc缓冲溶液中，刚果红与蛋白质(BSA或HSA)作用形成络合物，使刚果红-0．35V(vs SCE)的还原峰电流下降，峰电流的降低值同所加的BSA或HSA质量浓度在一定范围内呈线性关系；BSA和HSA的线性范围分别为0．5～12mg／L和0．5～11mg／L，检出限分别为0．25和0．20mg／L；运用该法测定了人血清白蛋白样品，结果令人满意。     

Macroporous poly(methyl methacrylate) produced by phase separation during polymerisation in solution

Polymethyl methacrylate (PMMA) sponges were obtained by polymerization in a solution with monomer/ethanol ratios up to 20:80. The material obtained after the elimination of the solvent present a homogeneous distribution of dispersed pores up to a monomer/ethanol ratio lower than 40:60. For higher ethanol contents in the reacting mixture, the morphology of the sponge corresponds to a network of PMMA microparticles, leaving large empty spaces leading to highly porous structure. The monomer/ethanol ratio during polymerization has a large influence on the porosity, thermal, and mechanical properties of the material and, for large solvent contents, on the size of the polymer microparticles.