Methyl scanning: total synthesis of demethylasterriquinone B1 and derivatives for identification of sites of interaction with and isolation of its receptor(s)

The principle of methyl scanning is proposed for determination of the sites of interaction between biologically active small molecules and their macromolecular target(s). It involves the systematic preparation of a family of methylated derivatives of a compound and their biological testing. As a functional assay, the method can identify the regions of a molecule that are important (and unimportant) for biological activity against even unknown targets, and thus provides an excellent complement to structural biology. Methyl scanning was applied to demethylasterriquinone B1, a small-molecule mimetic of insulin. A new, optimal total synthesis of this natural product was developed that enables the family of methyl scan derivatives to be concisely prepared for evaluation in a cellular assay. The results of this experiment were used to design a biotin-demethylasterriquinone conjugate for use as an affinity reagent. This compound was prepared in tens of milligram quantities in a four-step synthesis.     

Behaviour of organic pollutants in paper and board samples intended to be in contact with food

This paper deals with the study of volatile compounds present in a set of three paper and board (P&B) samples of different composition, surface treatment, grammage and thickness. The volatile compounds released by the packaging material (P&B) can be trapped on the food and may then affect the safety and health of consumers. To evaluate if the recycled P&B could be used as food packaging material, adsorption studies have been performed with a selection of chemical substances. The adsorption isotherms are provided. Partition coefficients between paper and air have been calculated for a series of volatile compounds used as model compounds to represent different families of contaminants commonly present in P&B. Values from 4 to 3243 were obtained at different temperatures. The analysis of volatile compounds have been carried out by automatic headspace coupled on-line with GC/MS in SIM mode. The results obtained are shown and discussed.     

A quantum scattering study of collinear state-testate reaction probabilities for the F + H2(v) → HF(v') + H system

A new quantum scattering approach (linear combination of arrangement channels-scattering wavefunction, LCAC-SW) proposed by Deng and his co-workers is used to calculate collinear state-to-state reaction probabilities for the F + H₂(v) → HF(v') + H system. Several interesting problems such M threshold energy, compound states and enhance by translational energy of the reactants and the vibration excitation of products are discussed and they are compared with other theoretical investigations reported in the literature. It is shown that the LCAC-SW approach is the successful one of quantum scattering methods.     

Synthesis and Crystal Structure of MnSm_4(SiO_4)_3O

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(Pd-Cu)/C上苯乙烯氧化羰化合成肉桂酸甲酯的研究

在常压130℃下研究了Pd-Cu催化剂组成,反应温度,少量添加剂和原料气中O_2含量等对苯乙烯氧化羰化合成肉桂酸甲酯的影响,并对催化剂的形、相态进行表征.发现O_2有双重作用;O_2不仅使Pd-Cu之间的价态循环,而且能抑制反应过程中饱和苯丙酸甲酯的生成.指出催化反应中Pd-Cu之间的催化协同效应促进了产物的生成.初步讨论了本反应的机理.     

含钼化合物及其配合物的抗癌抗肿瘤活性

钼是生命体所必需的微量元素。本文介绍了钼在人体中的作用，钼缺乏和钼过量对人体的影响，并介绍了含钼化合物以及配合物的抗癌抗肿瘤研究情况。     

Core/shell particles containing 3-(methacryloxypropyl)-trimethoxysilane in the shell: synthesis, characterization, and application

In comparison to the corresponding single-component counterparts, core/shell particles are widely used due to their better physical and chemical properties. The surface properties of core/shell particles evidently play an important role in the process of application. It is easy to deduce that surface properties mostly depend on the properties of the component in the shell. Therefore, desirable materials of shell are very significant for the study of composite materials, especially in core/shell field. It is well known that polysiloxane has excellent properties, such as the water repellency, high flexibility, low surface energy, and biocompatibility. Its application, however, is limited due to poor cohesiveness and poor film-forming properties. Recently, much endeavor has been made to overcome such flaws. It is found that polyacrylate is commonly considered for its good cohesiveness and excellent film-forming property. The combination of polysiloxane and polyacrylate has been shown to be important in the composite material field, especially as core/shell particles. Unfortunately, their hydrophobicity is considerably different and thus, the core/shell particles consisting of polyacrylate (PA)/polysiloxane (PSi) are hard to prepare by general seeded emulsion polymerization, and are also scarcely available in the literature. In this study, the new core/shell PA/PSi particles with poly(butyl methacrylate) (PA) as the core and poly(3-(methacryloxypropyl)-trimethoxysilane) (PSi) as the shell were prepared by dispersion polymerization under the kinetically controlled conditions. The characterization of the particles by TEM, DSC, particle size analyzer as well as static contact angle confirmed the formation of core/shell structure. The application of core/shell (PA/PSi) particles also has been considered and discussed here.TEM micrographs of core/shell (PA/PSi) particles.     

Yb3+在不同基质中基态分裂能的计算分析

利用晶体场理论,推导出Yb3+离子基态(2F7/2)与Nd3+离子基态(4I9/2)最大分裂能之间的关系式为△E(2F7/2)=1.4667△E(4I9/2),从实验数据拟合得到的关系式为△E(2F7/2)=1.0987△E(4I9/2).理论计算与实验拟合存在差异,分析了出现差异的原因,认为差异主要是由相同晶体场对于不同掺杂离子的影响即晶体场参数Nv值不完全相同而引起的.     

茂基稀土胺化物与异氰酸正己酯的反应-{(MeC5H4)2Yb[OC(NPh2)N(n-hexyl)]}2的合成及表征

茂基稀土胺化物(MeCp)2YbNPh2(THF)与异氰酸正己酯(n-HexylNCO)按11摩尔比反应, 分离出产物{(MeC5H4)2Yb[OC(NPh2)N(n-hexyl)]}2. 产物经元素分析和核磁共振表征, 并测定了其晶体结构. 配合物属三斜晶系, R-3空间群, 晶胞参数为a=2.9533(11) nm, b=2.9533(11) nm, c=1.5873(6) nm, V=11.9896(80) nm3, Z=9, Dc=1.562 mg·m-3, μ=3.536 mm-1 (Mo Kα), F(000)=5670, R=0.034, Rw=0.064. 该化合物具有二个对称氧桥的双分子结构, 并存在着由氮原子向中心金属镱分子内配位而形成的三环骨架, 中心金属镱的配位数是九, 整个分子呈中心对称.     

从奎宁到白三烯——-试论有机化学在医学科学中的重要作用

有机化学,特别是天然有机化学,是和医学科学密切相关的,有机化学的成就在许多方面促进了医学科学的进步,反过来医学科学中提出的课题也推动了有机化学的发展。本文以抗疟药等天然药物和廿碳酸类等生理活性物质为例讨论了这两门学科间的一些关系。