Monosaccharides with Phosphorus in the Sugar Ring

Abstract

In recent years attention has been directed toward the synthesis of modified sugars wherein the oxygen atom in the sugar ring is replaced by sulfur, selenium or phosphorus. Synthesis of sugar analogs with phosphorus as the ring heteroatom is interesting from the point of view of their possible biological activity.     

Totally Synthetic Routes to the Higher Monosaccharides

The evolution of a strategy to synthesize the title compounds is described. Three principal developments allowed realization of this goal: (1) the attainment of high margins of diastereofacial selectivity and regioselectivity in the construction of pyranoid systems via the Lewis acid-catalyzed cyclocondensation reaction of activated dienes and aldehydes; (2) the exploitation of stereoselective reactions for functionalization of the pyranoid matrix; and (3) the discovery of stereoselective reactions for extending the chiral biases of pyranoid systems to newly emerging stereogenic centers on side chains. The coordination of these components in the synthesis of target systems of high biological interest is described.     

Ion Chromatographic Analysis of Monosaccharides and Disaccharides in Raw Sugar

A simple and effective method using ion chromatography was developed for the simultaneous determination of five monosaccharides (arabinose, glucose, fructose, xylose, and ribose) and two disaccharides (sucrose and lactose) in raw sugar samples. The separation was performed on a CarboPac PA 10 column using the gradient elution of sodium hydroxide and water as the mobile phase. Monosaccharides and disaccharides were detected by an integrated pulsed amperometric detection (IPAD) using gold working electrode. Acid hydrolysis was used for sample preparation before the analysis of glucose and fructose. All the studied sugars showed good linear ranges within 0.5–100 µg mL⁻¹ with the correlation coefficients higher than 0.997. The limits of detection were all less than 0.5 µg mL⁻¹. The RSDs of the method were less than 10 %. The recoveries of the sugars that spiked in raw sugar samples ranged from 96.1 to 102.4 %. The method was successfully applied for the analysis of sugars in raw sugar samples. Sucrose is the major constituent found in the samples at 97 %.

     

Preparation of New Wittig Reagents and Their Application to the Synthesis of alpha,beta-Unsaturated Phosphonates

The Wittig reagent [(diethoxyphosphinyl)methylidene]triphenylphosphorane (1b) has been successfully synthesized for the first time via its phosphonium triflate salt (4a), by treating (diethoxyphosphinyl)methyl triflate with triphenylphosphine. The procedure has been applied to the synthesis of other phosphoranes and phosphonium salts. The new Wittig reagents thus synthesized were treated with various aldehydes and an activated ketone, affording the corresponding alpha,beta-unsaturated phosphonates. Triphenylphosphorane 1b and triphenylphosphonium 4a led to both cis and trans isomers with the latter being predominant, while trans isomers were almost exclusively formed when tributyl reagents (1c and 4d) were used.     

Direct Aryloxylation/Alkyloxylation of Dialkyl Phosphonates for the Synthesis of Mixed Phosphonates

A strategy for the direct functionalization strategy of inertial dialkyl phosphonates with hydroxy compounds to afford diverse mixed phosphonates with good yields and functional‐group tolerance has been developed. Mechanistic investigations involving both NMR studies and DFT studies suggest that an unprecedented highly reactive P^V species (phosphoryl pyridin‐1‐ium salt), a key intermediate for this new synthetic transformation, is generated in situ from dialkyl phosphonate in the presence of Tf₂O/pyridine.     

Application of Supercritical Carbon Dioxide for the Preparation of Drug-Cyclodextrin Inclusion Compounds

Inclusion complexes of drugs into cyclodextrins (CDs) can be obtained at the solid state by means of supercritical dioxide (SCCO₂). A successful inclusion with a yield >98.5% has been achieved with piroxicam and -CD. The temperature and the time of exposure to SCCO₂ have a significant effect on the inclusion yield while the pressure has a negative effect. However, there is a strong interaction between temperature and pressure and this interaction has a positive influence. The molar ratio piroxicam--CD and the addition of ternary alkaline agents were also found to be significant factors. The dissolution rate of the complexes formed using SCCO₂ was found to be significantly higher than that of the physical mixture. Inclusion complexes have also been obtained with miconazole treating mixtures of miconazole, CDs and citric acid by SCCO₂. This new technique of inclusion of poorly soluble drugs into CDs allows the preparation of solid complexes without using organic solvents and thus without residues.     

核壳式氯霉素分子印迹聚合物碳纳米管复合材料的制备及应用

本文以多壁碳纳米管(MWCNTs)为载体,采用溶胶-凝胶法先在MWCNTs表面包覆硅层,得到MWCNTs@SiO2,再以氯霉素(Chloramphenicol,CAP)为模板,无水乙醇为溶剂,氨丙基三乙氧基硅烷(APTES)和苯基三甲氧基硅烷(PTMOS)为双功能单体,四乙氧基硅烷(TEOS)为交联剂,采用表面分子印迹技术合成具有核壳结构的CAP分子印迹聚合物包覆的碳纳米管复合材料。采用透射电镜(TEM)、红外(IR)光谱和热重(TG)分析技术对CAP分子印迹聚合物复合材料的结构、形貌进行了表征,并对其吸附性能进行了详细研究。结果表明,制备的分子印迹聚合物吸附动力学快,吸附容量大,选择性好,印迹因子达到4.2,并且可循环使用。将制备的分子印迹聚合物材料应用于实际样品鸡蛋中CAP含量的测定,回收率可达72.3%~84.1%。     

Review Article: Anionic Conjugate Addition Reactions for the Preparation of Substituted Monosaccharides and Disaccharides

1. INTRODUCTION

Conjugate addition reactions are widely used synthetic tools in general organic chemistry,¹ and starting in the early 1960s they were introduced into carbohydrate chemistry. Since then a considerable number of publications have described the utilisation of different types of conjugate addition reactions in the field of carbohydrate chemistry but to date this area has not been reviewed.     

5-氟脲嘧啶选择性碳糊电极的研制与应用

研制了以５ － 氟脲嘧啶离子与汞离子的摩尔比为１ ∶１ 的配位化合物作为电活性物质的５ － 氟脲嘧啶碳糊电极, 得到了良好的电极响应曲线, 线性范围为３ 个数量级, 检出限为１０ － ３ ｍ ｍｏｌ·Ｌ－ １ 。电极稳定性较好, 具有较好的抗干扰能力。采用直接电位法测定商业药品, 结果令人满意。     

糖蜜基多孔碳球电极材料的制备及应用

以工业制糖的副产物糖蜜为新型碳源,替代传统多孔碳生产原料,制备出性能优异的多孔碳球超级电容器电极材料;探索了制备方法,优化了反应条件.利用全功能表面吸附仪、扫描电子显微镜及电化学方法对材料的结构、形貌和电化学性能进行了表征.结果表明,制得的多孔碳球比表面积高达2547 m~2/g,且展现出优异的双电层电容性(170.5 F/g).本研究可解决制糖企业对糖蜜无法大规模利用的问题,并为多孔碳的制备寻求新方法.     

碳柱热电极的制备及应用

用铅笔芯制作了不同直径的碳柱热电极,表征了碳柱热电极的电化学和温敏等各种性质。结果表明,碳柱热电极在多次加热过程中均表现出对温度变化的快速响应以及良好的热稳定性。将其应用于痕量铅的方波阳极溶出伏安法测定,65℃时灵敏度比常温高,Pb2＋浓度在1~22μg/L呈线性关系,线性回归系数r=0.995 5,检测限0.5μg/L。     

有机膦酸铜化合物的合成、结构及性质

由于在分子识别、传感器、催化等方面的潜在应用前景，近年来金属有机膦酸化学研究引起了人们广泛的关注。本文介绍有机膦酸铜化合物的结构、合成及性质研究方面所取得的一些进展。     

Preparation of Multiwall Carbon Nanotubes-supported High Loading Platinum for Vehicular PEMFC Application

Multiwall carbon nanotube-supported Pt （Pt/MWNTs） catalysts with high dispersion and high loading of Pt were prepared by chemical reduction method and the loading of Pt got to 40 wt%. The average diameter of Pt nanoparticles on MWNTs was about 3.5 nm. When the hydrogen and air were used as reactant gases for PEMFC, Pt/MWNTs catalysts showed significantly higher performance than the Pt/XC-72 （carbon black） catalysts.     

新型超支化聚合物修饰碳糊电极的制备及应用

制备了超支化聚(胺-酯)化学修饰碳糊电极,研究了Cu2+在修饰电极上的电化学行为.在0.25 mol/L KCl溶液(pH 4.0)中, Cu2+与超支化聚(胺-酯)形成电化学包络物,分别于0.27和0.06 V处产生一对灵敏的氧化还原峰,具有明显的催化还原增敏作用.研究了超支化聚合物结构和代数对电极性能的影响.实验表明: 5代超支化聚合物修饰电极性能最好.建立了线性扫描伏安法测定痕量铜的方法,线性范围1.0×10-8 ～ 3.0×10-5 mol/L;检出限为4.0×10-9 mol/L. 用于人发样品的测定,获得满意结果.     

Preparation of Aminovinyl Phosphonates by Four-Component Aminoalkylation of Aldehydes Mediated by Lithium Perchlorate

Several aminovinyl phosphonates were prepared in good yield by four-component aminoalkylation of aldehydes with diethyl(trimethylsilyl)amine, triethylphosphite and dimethyl acetylenedicarboxylate mediated by a 5 molar solution of lithium perchlorate in diethyl ether.     

网状玻璃碳光谱电化学池的制作及应用

制作了一种以网状玻璃碳为工作电极的光谱电化学池,并介绍了对网状玻璃碳电极的处理方法。选用铁氰化钾-亚铁氰化钾体系,对其式量电位(E°′)、反应电子数(n)和扩散系数(D_R)进行了测定,取得较为满意的结果。     

单糖乙酰化条件的优化

利用气相色谱-质谱联用技术（GC-MS）检测5种常见单糖（木糖、阿拉伯糖、甘露糖、葡萄糖、半乳糖）的乙酰化产物含量。为在预衍生化中取得较高的效率,采用正交试验综合考察了还原时间、还原温度、乙酰化温度、乙酰化时间等因素对单糖回收率的影响及规律。结果表明,影响最为显著的因子为还原温度和乙酰化时间。总结出了单糖衍生化最佳的反应条件为还原温度50℃、还原时间2．5h;乙酰化温度90℃、乙酰化时间2．5h。     

炭载二氧化锰的制备和锂离子超级电容器性能的研究

制备了炭气凝胶载二氧化锰(AG-MnO₂)复合材料, 材料物理化学表征表明, 在炭气凝胶表面和微孔内沉积二氧化锰, 改善了炭气凝胶的电化学性能. 以炭二氧化锰复合材料为负极, LiMn₂O₄为正极, 设计出一种新型的高能量密度混合电容器, 并研究了负极工作电位范围对电容器性能的影响. 研究结果表明, 引入高容量的AG-MnO₂复合材料, 并通过扩大负极工作电位区间, 可设计出能量密度高达92 Wh•kg^－1(基于正负极活性质量)的混合电容器, 为炭对称电容器的5倍. 这种混合电容器经过1000次循环, 容量仍然保持在80%以上.