2,2'-Dimercaptodiethylsulphide: A potential analytical reagent

The compound 2,2'-dimercaptodiethylsulphide has been investigated with regard to the stability of its solutions to air oxidation, its acid strength, its reactivity towards metal ions, the nature of its Ni(II) and Pd(II) complexes in solution, and its applicability to the determination of small amounts of Ni(II) and Pd(II). Studies on the Ni(II) complex extend the work reported previously by others and are not in complete accord with it. The results presented show that 2,2'-dimercaptodiethylsulphide is a promising analytical reagent.     

Medicines, monopolies and mortars: the chemical laboratory and pharmaceutical trade at the Society of Apothecaries in the eighteenth century

In 1672, a laboratory was founded by the Society of Apothecaries at its premises in Blackfriars, London, to manufacture chemical medicines. By exploring the society's motivations for constructing a laboratory and its development during the eighteenth century, this paper examines the roles that chemistry played within the activities of the institution. While the chemistry's primary utility was in drug manufacturing for the society's pharmaceutical trade, through its laboratory, the society used chemistry to develop its corporate and educational aims, thus helping to secure its institutional authority in London's medical marketplace.     

Structure elucidation of nigricanoside A through enantioselective total synthesis

Nigricanoside A was isolated from green alga, and its dimethyl ester was found to display potent cytotoxicity. Its scarcity prevented a full structure elucidation, leaving total synthesis as the only means to determine its relative and absolute stereochemistry and to explore its biological activity. Here we assign the stereochemistry of the natural product through enantioselective total synthesis and provide initial studies of its cytotoxicity.     

Cryoscopy on sulfuric acid solutions of a heterocyclic polymer (BBB) and related compounds

Cryoscopic measurements have been carried out on solutions in sulfuric acid of a heterocyclic polymer, its monomers, and certain of its oligomers. The polymer, BBB, is prepared by the polycondensation of 1,4,5,8-naphthalenetetracarboxylic acid (NTC) with 3,3′-diaminobenzidine (DAB). The results show that the polymer, its oligomers and one of its monomers, DAB, are all extensively protonated in sulfuric acid, whereas its other monomer is not. The degree of protonation appears to be greater for the polymer than for its low molecular weight oligomers.     

聚乙二醇对人血清IgG的化学修饰及修饰后性质的研究

本文以三聚氯氰为活化剂，单甲氧基聚乙二醇（ＰＥＧ）５０００为载体，对人血清免疫球蛋白Ｇ（ＩｇＧ）进行化学修饰，修饰ＩｇＧ与未修饰ＩｇＧ比较，随修饰度的增高，分子量增加，保留活性降低，对温度及ｐＨ的耐受性增加，抗原性及免疫原性明显下降，ＩｇＧ的骨架结构在修饰前后无明显变化。     

Information requirements for chemists in the pharmaceutical industry

The principal information needs of chemists in the pharmaceutical industry center around a substance, methods used for its characterization, its reactions, its physicochemical and biomedical properties, and its metabolic fate in biological media. Novelty searches for a specific chemical are critical because of the need for patent protection for product candidates. Chemical relatives are important, necessitating substructure searching. Therapeutic neighbors may give insight into its biological mode of action. The phases of drug discovery and development are used to indicate the diversity of the information needs of chemists and to emphasize the dual process of generation and use of information.     

Catecholamine: „On-Line” probenaufarbeitung und nachsäulenderivatisierung

Summary We developed an automated, two-column HPLC-method that can be used routinely to quantify the catecholamines norepinephrine and epinephrine in body fluids. The method is based on a new, laboratory-prepared SEC-HPAC column material, on the application of a microprocessor-controlled column-switching technique, and on the use of an integrated reaction system for postcolumn derivatization and trihydroxyindol-fluorescence monitoring. It allows the direct injection (upto 500 μl) of an appropriate biological fluid and distinguishes on its integrated sample-processing mode, its practicability, its chemoselectivity and-specivity, its detection limit (2 pg), its within- and between-run precision and its speed of analysis.

     

Preparation and Characterization of Zirconia-Magnesia Support Modified by Alkylphosphonic Acid for Liquid Chromatography

Interest in zirconia as a chromatography support has increased considerably recently because of its chemical inertness and its promise as a useful support. We have reported the preparation of spherical zirconia and characterization of its chromatographic behavior. However, the zirconia was found unsatisfactory for its chromatographic efficiency, probably owing to the poor pore structure of it. In this paper, we for the first time report the preparation of alkylphosphonic acid modified zirconia-magnesia stationary phase, and characterization of its structure and chromatographic behavior.     

壳聚糖及其衍生物抗菌活性的研究进展

壳聚糖是自然界目前发现的唯一碱性多糖,具有自然来源丰富,生物相容性好,可被生物降解,安全无毒和抗菌性强等许多天然的优良特性,现其广谱抗菌性已得到广泛的认可,但较差的水溶性限制了它的进一步应用。因此,通过一定的改性方法制备壳聚糖衍生物以提高其水溶性,是目前壳聚糖研究方面的热点之一。本论文就近年来几种常见的壳聚糖亲水改性方法及其衍生物在抗菌方面的应用进展进行综述,以期对壳聚糖的深入研究提供参考。     

Medicines,Monopolies and Mortars: the Chemical Laboratory and Pharmaceutical Trade at the Society of Apothecaries in the Eighteenth Century

Abstract

In 1672, a laboratory was founded by the Society of Apothecaries at its premises in Blackfriars, London, to manufacture chemical medicines. By exploring the society's motivations for constructing a laboratory and its development during the eighteenth century, this paper examines the roles that chemistry played within the activities of the institution. While the chemistry's primary utility was in drug manufacturing for the society's pharmaceutical trade, through its laboratory, the society used chemistry to develop its corporate and educational aims, thus helping to secure its institutional authority in London's medical marketplace.     

Determination of hydroxycamptothecin affinities to albumin and membranes by steady-state fluorescence anisotropy measurements

Camptothecin (CPT) and its hydroxycamptothecin analogs are fluorescent compounds exhibiting strong anticancer properties. They exist in two forms: active lactone and inactive carboxylate. The deactivation proceeds via hydrolysis in neutral and base solutions. A serious limitation to the clinical application of CPT is the strong affinity of its carboxylate form to human serum albumin (HSA) which destabilizes its active lactone form. However, binding to membranes in blood improves the stability of the lactone form of CPT and its analogs. A high-throughput screening assay based on the steady-state fluorescence anisotropy method was used to determine the protein- and membrane-binding properties of 10 hydroxycamptothecin (10-OH-CPT), 7-ethyl-10-hydroxycamptothecin (SN-38) and 7-tert-butyldimethylsil-10-hydroxycamptothecin (DB-67). The relative affinities of hydroxycamptothecins to HSA and model membranes in the form of DMPC liposomes were determined, and DB-67 exhibited the most desirable properties including the highest affinity to membranes in its lactone form and low affinity to HSA in its carboxylate form.     

Application of total selective solvent extraction of germanium,phosphorus and silicon to the simultaneous determination of arsenic,germanium, phosphorus and silicon

A simple rapid, accurate, and reliable method of simultaneous determination of arsenic, germanium, phosphorus, and silicon is reported. The method involves first, the determination of germanium as its phenlfluorone complex and its selective extraction with isoamyl alcohol. Phosphorus is next determined as its heteropoly blue after selective extraction of phosphomolybdic acid by isobutyl acetate at pH 1.0-0.8 and its direct reduction in this solvent. Silicon is then determined after its extraction as silicomolybdic acid by isooctyl alcohol at pH < 0.4 and direct reduction in the solvent phase. Finally, arsenic is determined in the remaining aqueous phase after reduction to its heteropoly blue.     

Self-assembly of Amphiphilic Diblock Copolymers Induced by Liquid-Liquid Phase Separation

The liquid-liquid phase separation(LLPS)widely exists in biology,synthetic chemistry,crystallization kinetics and other fields,and it is very important to realize the related functions.The research on the competition between LLPS and micellization/vesiculation has made considerable progress.However,the way to effectively control the formation paths from homogeneous state to aggregates has not been completely solved,which is vital to determine its structure and properties and even its future functions.Here we describe the phenomenon of LLPS and its effect on the dynamic process of self-assembly of amphiphilic diblock copolymers(BCPs).Starting from the establishment of phase diagram,we explore the existence conditions of LLPS state,the internal morphology and external size of large droplets,and its significant implications to the dynamic path of vesicle formation.Vesicles formed via LLPS have larger sized outer dimensions and inner cavities,and contain more solvents during certain stages.The detailed research of LLPS and its self-assembly simulation has contributed to completing its theoretical basis and practical applications in the future in various fields.     

天然产物色胺酮及其衍生物合成的研究进展

综述了色胺酮及其衍生物的合成方法。大部分方法都是以吲哚醌和吲哚酮为起始原料,其中吲哚醌和靛红酸酐反应合成色胺酮及其衍生物的方法较为理想。由于色胺酮类化合物具有很好的抗癌、杀菌和消炎等生物活性,新的简捷、低成本合成方法的开发仍然是必要的。     

透明质酸及其衍生物作药物载体

透明质酸(HA)具有良好的生物相容性和生物降解性，是优良的药物载体。但其稳定性差，对强酸、强碱、热、自由基及透明质酸酶敏感，容易发生降解而限制了其应用。本文简要介绍HA的基本特性及应用，重点阐述了HA经不同的化学改性方法如酯化、交联、接枝所得衍生物作药物载体的最新研究进展。化学改性赋予了HA一系列的优良特性,如适当的机械强度、特殊的流变学特性、良好的稳定性、靶向性等,可提高、扩大HA作药物载体的性能和应用范围。最后展望了透明质酸及其衍生物作药物载体的应用前景。     

On the Structure of Poly-(Ethylene Oxide) When Immersed in Water

It can be shown that poly-(ethylene oxide) in its monomeric form, at molecular weights greater than about 1,000, cannot be soluble in water. Nonetheless, in actual practice poly-(ethylene oxide) is widely used for its hydrophilicity and for its unlimited aqueous solubility. The explanation for this apparent contradiction lies in the fact that poly-(ethylene oxide) molecules form a nonionic surfactant of a novel category, with its hydrophilic and hydrophobic chains attached to each other over their entire length so that its hydrophilic ethylene oxide side is exposed to the water interface while the hydrophobic poly-(ethylene) side remains hidden thanks to the formation of micelles.     

Pentagermapyramidane: Crystallizing the “Transition‐State” Structure

The first example of the homonuclear pyramidanes, pentagermapyramidane, was synthesized, fully characterized, and computationally studied to reveal its peculiar structural features and the nature of its apex‐to‐base bonding interactions. Both solid‐state and solution structures of pentagermapyramidane are discussed based on the computed stabilities of its square‐pyramidal and distorted forms.     

Size-Exclusion Chromatography: A Twenty-First Century Perspective

Now in its sixth decade, size-exclusion chromatography (SEC) remains the premier method by which to determine the molar mass averages and distributions of natural and synthetic macromolecules. Aided by its coupling to a variety and multiplicity of detectors, it has also shown its ability to characterize a host of other physicochemical properties, such as branching, chemical, and sequence length heterogeneity size distribution; chain rigidity; fractal dimension and its change as a function of molar mass; etc. SEC is also an integral part of most macromolecular two-dimensional separations, providing a second-dimension size-based technique for determining the molar mass of the components separated in the first dimension according to chemical composition, thus yielding the combined chemical composition and molar mass distributions of a sample. While the potential of SEC remains strong, our awareness of the pitfalls and challenges inherent to it and to its practice must also be ever-present. This Perspective aims to highlight some of the advantages and applications of SEC, to bring to the fore these caveats with regard to its practice, and to provide an outlook as to potential areas for expansion and growth.

     

Density functional theory (DFT) investigation of the oxidative degradation of NaAsO2 via hydroxyl radical

Structural Chemistry - Arsenic is an environmentally ubiquitous health hazard due to its toxicity combined with its natural abundance and heavy industrial applications. Due to its role in...