A Facile Synthesis of Ethyl 2,4-Dimethoxy-6-perfluoroalkyl-benzoates via Acyclic Precursors

Introduction Polysubstituted arenes are important intermediates in synthetic medicines and dyestuffs, and the fluorinated analogues are more attractive as a result of their lipo-philicity and the increment of activity.1,2 Therefore, to study the convenient and efficient synthesis of polysub-stituted arenes is valuable in organic synthetic method-ology. We have designed a simple synthesis of fluori-nated polysubstituted arenes through the intramolecular Wittig reaction of a new phosphorous ylid…     

Low Dimension Semiconducting Composite Nanomaterials

Recently, low dimension nanostructures have gained considerable attention due to their technological potential as unique types of nanoscale building blocks for future optoelectronic devices and systems. Semiconducting composite nanomaterials, which can combine the advantages of two or more components, have been the focus in the area of nanomaterials synthesis and device application.In this paper, we report our work on the preparation of composite nanomaterials based on CNTs.CNTs were coated by organic or inorganic species via novel and facile methods (Fig. 1 and Fig.2).These functional CNTs based composites show eminent prospects and opportunities for new applications in a wide variation of areas.     

APPLICATION OF MSW-X_α METHOD WITH OVERLAPPING ATOMIC-SPHERE TO IONIZATION POTENTIALS FOR SOME PLANAR ORGANIC MOLECULES

Application of multiple scattered-wave X_α method with overlapping atomic-sphere to ionization potentials is reported for benzene, pyridine, pyrazine, pyrrole and imidazole. The calculated results show that the orbital charges in the intersphere region are non-negative and the energy levels get improvements in orderings.     

SYNTHESIS AND PHOTOCHROMISM OF ACRYLIC ESTER COPOLYMERS BEARING PENDANT VIOLOGEN GROUPS

A series of acrylic ester copolymers with viologen group as pendant were synthesizedthrough the reaction of MMA-EBA (Ethenyl bromoacetate) copolymer with 4-(4'-pyridyl)-N-alkyl (or arylalkyl) pyridiniums. These viologen copolymers can exchange their anionwith NH_4PF_6 in methanol to improve their solubility in organic solvents such as DMFand acetone. Compared with the corresponding low molecular viologens, these viologencopolymers have relatively lower color development rate under UV light and fade fasterin air due to less affinity to photo-reductant and deficiency of association between theircation radicals. Their photofatigue resistant ability is also slightly better than that of lowmolecular vinlogens.     

Synthesis of Polyacrylaminothiourea Chelating Fiber and Properties of Concentration and Separation of Trace Noble Metal Ions from Samples

A novel polyacrylaminothiourea chelating fiber was synthesized simply and rapidly from nitrilon (an acrylonitrile-based synthetic fiber), which was applied to preconcentrate and separate of trace amount of Au(Ⅲ）,Pt(Ⅳ）,Pd(Ⅳ） and Ir (Ⅳ） ions from solution of samples.The analyzed ions can be quantitatively concentrated by the fiber up to a flow rate of 20.0mL/min at pH2, and can also be desorbed with 15 mL of 4mol/L HCl 3% thiourea from the fiber column with recoveries of 96.5%-100%.The chelating fiber can be reused for ten times,the recoveries of these ions are still over 92%,and hundred to thousand times of excess of Fe(Ⅲ）,Al（Ⅲ）,Ca(Ⅱ），Mg（Ⅱ）,Ni(Ⅱ）,Mn（Ⅱ),Cu(Ⅱ），Zn(Ⅱ），and Cd(Ⅱ） cause no interference on the determination of the analyzed ions by inductively-coupled plasma atomic emission spectrometry (ICP-AES).The static saturation adsorption capacities of the fiber for the analytes are in the range of 1.15-2.80mmol/g.The relative standard deviations for the determination of 20.0ng/mL each of Au(Ⅲ）,Pt(Ⅳ）,Pd(Ⅳ）and Ir(Ⅳ） are in the range of 0.7%-3.0%.The recoveries for test from standard additions to real solution samples are between 96% and 100%.The concentration of each ion in powder sample detected by the method is in good agreement with the certified value.     

LC-MS法分析鸡肝中的玉米赤霉醇

玉米赤霉醇(Zeranol)是一种非甾体类激素,具有促进家畜蛋白质合成和增重的作用。由于其在动物组织中残留,目前在欧盟被禁用。2002年4月我国农业部第193号公告和2002年11月农业部、国家药品监督管理局第227号公告中规定禁止使用玉米赤霉醇,但由于玉米赤霉醇作为畜禽增重剂效果好、经济回报高,仍有一些不法饲养业主受利益驱使而违法使用。为保证动物源性食品安全,维护人民身体健康,必须建立一种适用、可行、规范的残留检测方法以适应当前加入WTO的形势需要。本实验建立了高效液相色谱-质谱联用法(LC-MS)测定鸡肝中玉米赤霉醇,旨在为政府监控禽类产品中的玉米赤霉醇提供准确可靠的检测方法。     

1,6-二氢-S-四嗪催化重排及其反应的研究--Ⅱ. 与氯甲酸三氯甲酯反应

在4－二甲胺基吡啶的存在下，1，6－二氢－S－四嗪重排成3，6－二氢－S－四嗪，与双光气反应后再与不同的胺反应，合成了11种1，4－二取代产物，产物经元素分析、IR和^1H NMR确证。用UV和^1H NMR分析结果对反应机理进行了初步探讨。     

A New Asterosaponin from the Starfish Culcita novaeguineae

A new asterosaponin named novaeguinoside A, along with a known saponin, asteronyl pentaglycoside sulfate, was isolated from the starfish Culcita novaeguineae. The new compound was identitied to be sodium 6α-O-{β-D-fucopyranosyl-(1→2)-β-D-fucopyranosyl-(1→4)-[β-D-quinovopyranosyl-(1→2)]-β-D-xylopyranosyl-(1→3)-[β-D-quinovopyranosyl}-5α-pregn-9(11)-en-20-one-3β-yl-sulfate by extensive spectral analysis and chemical evidence.     

MOLECULAR WEIGHT DISTRIBUTION OF AB, A, TYPE CONDENSATION POLYMERS OBTAINED BY ADDING AB MONOMERS IN BATCHES

The molecular weight distribution (MWD) and arm length distribution of AB, Ar type condensation polymers obtained by adding AB monomers in batches have been derived by statistical and kinetic methods. Calculations show the MWD of condensation polymers obtained by this process is much narrower than that of one batch reaction and agrees with the Monte Carlo results very well.