三芳基膦配体的合成研究

从间溴苯酚出发, 利用新的合成方法经五步反应合成了一系列具有不同烷氧基的芳基膦配体. 改进后的方法可方便地通用于在苯环上具有各种不同基团基的膦配体衍生物的合成, 且有原料易得、操作简单、产率较高的优点.     

A Facile Three-Component One-Pot Synthesis of Structurally Constrained Tetrahydrofurans, Which Are t-RNA Synthetase Inhibitor Analogues

A one-pot procedure for the efficient synthesis of a small library of t-RNA inhibitor analogues was developed. Thus,Rh2(OAc)4 catalyzed three-component 1,3-dipolar cycloaddition reactions of carbonyl ylides derived from diazoindan-1,3-dione and aldehydes with other dipolarophiles in 1,1,2,2-tetrachloroethane at 80 ℃ gave ring fused tetrahydrofurans having three stereocenters in good yield.     

Synthesis and Reactivity of (β-Amino-α-acylalkenyl)phenyliodonium Salts

During the last few years alkenyl(phenyl)iodonium salts have risen from mere chemical curiosities to valuable synthetic intermediates. [1] Because of an excellent leaving group ability of a phenyliodonyl moiety, alkenyl(phenyl) iodonium salts undergo nucleophilic vinyl substitutions under mild conditions, thus providing a useful route for the synthesis of various kinds of olefins. Recently, some of functionalized alkenyl iodonium salts have been prepared. [2]     

Analysis of Equilibrium and Kinetics of Chromium-Fluoride Complexation from Spectroscopic Data via Chemometrics Methods

IntroductionStudies on reversible kinetic systems are consi-dered as a hotspot of chemical and biochemical kineticresearches[1,2]. Of late, some researches have been fo-cused on the simultaneous optimization of the obverseand reverse rate constants[3,4].H…     

Polymer-enzyme conjugates can self-assemble at oil/water interfaces and effect interfacial biotransformations

Native water-soluble enzymes were transformed into interface-binding enzymes via conjugation with hydrophobic polymers, thus enabling interesting interfacial biocatalysis between immiscible chemicals at oil/water interfaces. Such interfacial biocatalysis demonstrated a significantly improved catalytic efficiency as compared to traditional biphasic reactions with enzymes contained in the bulk aqueous phase. Particularly, polystyrene-conjugated beta-galactosidase showed a catalytic efficiency that was more than 145 times higher than that of the native enzyme for a transgalactosylation reaction. It is believed that the improved accessibility of the biocatalysts to chemicals held in both phases across the interface is the key driver for the enhancement of enzyme activity.     

1.5-Diaza-3.7-diphospha-cyclooctane

The alkyl (aryl)-bishydroxymethylphosphines react with primary amines to give the title compounds. With optically active amines optically active phosphines are formed.     

A convenient and efficient preparation of β-substituted α-haloenones from diazodicarbonyl compounds

Rhodium(II)-catalyzed reactions of cyclic diazodicarbonyl compounds with a variety of halides have been examined. With acid halides, β-acyloxy α-haloenones are produced in good yields. With benzyl halides, β-benzyloxy α-haloenones are obtained in good yields. Reactions with methylene halides yield β-halomethoxy α-haloenones in good yields, whereas reactions with ethyl halides and ethylene dihalides result in β-hydroxy α-haloenones in high yields. These reactions provide a useful and rapid entry to β-substituted α-haloenones. The mechanistic pathway for the formation of these products has been also described in terms of halonium ylides.     

LC-ESI-MS Determination of Bilobalide and Ginkgolides in Canine Plasma

A sensitive and selective method using liquid chromatography with electrospray ionization mass spectrometric detection was developed for the quantification of bilobalide and ginkgolides in canine plasma. The analytes were extracted with diethyl ether-dichloromethane-isopropanol (6:3:1, v/v) after spiking the samples with daidzein (internal standard). The lower limit of quantification (LLOQ) of the method was 2.5 μg L⁻¹ for ginkgolide B and 10.0 μg L⁻¹ for bilabolide, ginkgolide A and ginkgolide C. The accuracy of the method was within 15% of the actual values over a wide range of plasma concentrations. The intra-day and inter-day precision was better than 15% (R.S.D.). Finally, the LC-ESI-MS method was successfully applied to study the pharmacokinetics of ginkgolides and bilabolide after administration of Ginkgo biloba extracts to dogs.     

流动注射电化学发光测定维生素B1的研究

基于发现在强碱性介质维生素 B1对电生BrO-氧化Luminol的强化学发光有很强的抑制作用, 将在线恒电流电解产生BrO-与流动注射技术结合,建立了流动注射电化学发光测定维生素B1的新方法.该方法测定维生素B1的线性范围为1.0×10-8～6.0×10-6g·ml-1,检出限为3.2×10-9g·ml-1,相对标准偏差为1.2%(n=11).该法具有灵敏度高,可控性强等优点,用于片剂中的维生素B1含量测定,结果满意.     

Advanced Current Collectors for Alkali Metal Anodes

High-energy-density batteries are in urgent need to solve the ever-increasing energy storage demand for portable electronic devices, electric vehicles, and renewable solar and wind energy systems. Alkali metals, typically lithium(Li), sodium(Na) and potassium(K), are considered as the promising anode materials owing to their low electrochemical potential, low density, and high theoretical gravimetric capacities. However, the problem of dendrite growth of alkali metals during their plating/stripping process will lead to low Coulombic efficiencies, a short lifespan and huge volume expansion, eventually hindering their practical commercialization. To resolve this issue, a very effective approach is engineering the anodes on structured current collectors. This review summarizes the development of the alkali metal batteries and discusses the recent advances in rational design of anode current collectors. First, the challenges and strategies of suppressing alkali-metal dendrite growth are presented. Then the special attention is paid to the novel current collector design for dendrite-free alkali metal anodes. Finally, we give conclusions and perspective on the current challenges and future research directions toward advanced anode current collectors for alkali metal batteries.