Dendritic Macroinitiator for the Ring—Opening Polymerization of γ—Benzyl L—Glutamate N—Carboxyanhydride

Much effort has been dedicated to the molecular design and synthesis of model proteins to define protein folding interactions and to develop protein-based materials. Among them, the ring-opening polymerization of -amino acid-N-carboxyanhy- drides (NCAs) has drawn much attention because the resulting artificial polypeptides have wide applications in biotechnology, biomineralization and diagnostics1, 2. It is well known that dendrimers are hyperbranched macromolecules possessing a very high co…     

Indium (III) Tribromide : An Excellent Catalyst for Biginelli Reaction

A highly efficient catalyst indium (III) tribromide is used to synthesize 5-alkoxy- carbonyl-4-hydrocarbyl-3,4-dihydropyrimidin-2(1H)-ones by a three-component coupling of β-keto ester, aldehydes and urea through improved Biginelli reaction.     

聚丙烯/聚对苯二甲酸乙二酯共混自增强材料的研究(Ⅰ)

本文根据聚丙烯（ＰＰ）与聚对苯二甲酸乙二醇酯（ＰＥＴ）共混对在熔 融状态下．流动粘度差阳溶度参数差大的特点，用挤出造粒的方法制得 共熔成纤目增强材料。通过扫描电镜观察．证实ＰＰ／ＰＥＴ比从９５／５到 ８０／２０时。ＰＥＴ均以纤维状结构分布在ＰＰ基质中。该共熔成纤体具有 良好的机械性能。在未加偶联剂时，拉伸强度虽略比纯ＰＰ低．但抗冲击 强度与纯ＰＰ相当。该结果可用于指导ＰＰ的改性和ＰＥＴ废料再生利用 工作。     

A New Convenient Method for the Resolution of 1, 1''''-Binaphthalene-2, 2''''-diol Via a Phosphite Using (-)-Menthol as Resolving Agent

Optically active 1,1-binaphthalene-2, 2-diol has become a quite important chiral source in different fields of chirotechnology, especially in asymmetric synthesis1. Its synthesis and resolution has been extensively studied and various resolution methods have been reported2. Among the reported resolution methods, the following three, namely, via the formation of phosphoric acid derivatives3, boric acid derivatives4 and inclusion complexes5, are the most important. OHOH+_( )-1(-)-(S)-1(+)-(R)…     

Spacial Structure of Cationic Phosphorus Ligand–Ru (II) Halide Complexes—by DFT Study

The increasing demand to produce enantio-pure pharmaceuticals, flavors, and other fine chemicals has advanced the field of asymmetry catalytic technologies. Among all asymmetry catalytic methods, catalytic enantioselective hydrogenation of unsaturated bonds such as olefins, ketones, and imines, which employs dihydrogen and small amounts of transition-metal complexes modified intrinsically by chiral ligands, is now recognized as being the most promising strategy for the synthesis of large amount…     

The Purification of Glucose Type Glycosyl Nitrate and the Synthesis of Spacer—armed N—Acetyllactosamines and Their Dimers

Our previous paper1,2reported the results of selective synthesis of mannose type glycosides and their dimers in our attempt to synthesize derivatives of N-acetyllacto- samine, which could have potential activity of anti-metastasis3. Further studies on the glycosylation of the accepters exploiting glycosyl nitrate instead of the acetate as donor showed interesting chemoselectivity between the two kinds of donor, namely, the glucose type and the mannose type. The reactivity difference of the t…     

关于化学位移定义式的有关问题

在有关核磁共振技术的大学教材和专著中,给出了以下几种不同形式的化学位移(δ)定义式: δ=v_(样品)-v_(标准)/v_(标准)×10~6(1) δ=H_(样品)-H_(标准)/H_(标准)×10~6(2) δ=H_(标准)-H_(样品)/H_(样品)×10~6(3) δ=(1)式=(3)式(4) δ=(v_(样品)-v_(TMS))Hz/核磁共振仪所用频率MHz核磁共振仪所用频率MHz(5) 几种不同形式定义式的出现,对教学和自学造成了一定的困难.因为存在以下三个问题需要理解: 第一:以磁场强度(H)出发的定义式(2)和(3),为什么分子中相应各项的下标是相反的? 第二:以磁场强度(H)出发的定义式(3)和以频率(v)出发的定义式(1),分子中相应各项的下标也是相反的,为什么这两个式子是相等的(即(4)式)? 第三:若(4)式成立,为什么实际工作     

成形滤纸片薄样X射线荧光光谱法测定铝合金中镧铈镨钕钐

研究了用成形滤纸片薄样X射线荧光光谱法测定铝合金中的镧、铈、镨、钕、钐。方法具有准确、快速、简便、经济等优点。各元素的测定灵敏度为La 48054,Ce 65923,Pr 93953,Nd 62622,Sm107630 cps/(mg/cm~2)。定量分析下限约为0.xμg/cm~2。     

邻硝基苯丙酮酸乙酯烯醇钾的合成和乙醇钾的制备新方法研究

邻硝基苯丙酮酸乙酯烯醇钾的合成和乙醇钾的制备新方法研究张本才，李宝林，李安祥（陕西师范大学化学系，西安７１００６２）邻硝基苯丙酮酸乙酯烯醇钾用作合成邻硝基苯甲醛（一种难于合成的重要化工原料，主要用来生产硝苯吡啶等药物）的关键中间体早有报道￣［１，２］...     

Synthesis of a Polymer-bound Sensitizer and its Application in the Photoisomerization of trans-Vitamin D_3 to cis-Vitamin D_3

The photochemistry of the vitamin D family and their precursors has been the subject of extensive studies for many years1-4. Most of the studies focus on the photoisomer- ization of 7-dehydrocholesterol and that of tachysterol to previtamin D3, which is of commercial importance in the synthesis of vitamin D34, 5. Recently the cis/trans isomerization of vitamin D analogs (Scheme 1) draws attention because of its importance in the synthesis of hydroxylated vitamin D metabolites6. However, o…