羧酸及其衍生物的NaBH4还原体系研究进展

NaBH4还原体系可以快速、高效、选择性地还原羧酸及其衍生物。本文介绍了8类NaBH4还原体系的最近研究成果。通过对各个还原体系的分析,讨论了各类还原体系的反应机理和反应条件,并比较了不同还原体系的还原能力和适用范围。     

缩聚反应相对分子质量的控制与计算

根据缩聚反应相对分子质量控制理论,分析了经典体系、端基封锁体系和综合体系中平均聚合度或相对分子质量的准确计算公式。     

联用技术在生物体系化合物分析中的应用进展

介绍了目前分离分析生物体系化合物的一般步骤和注意事项.综述了联用技术在生物体系化合物分析中的应用进展情况.展望了联用技术在生物体系化合物分析中的发展方向和应用前景.     

双极性电化学的概述及研究进展

作为近年来快速发展的一种便携、阵列、简单的电化学体系,双极性电化学在分析检测、材料制备、物质筛选等领域受到研究者的青睐。简要介绍了双极性电化学的特点,介绍了双极性电极（BPE）体系的2种主要装置：开放性BPE和封闭性BPE。并以开放性BPE体系为例,着重阐述了BPE体系的电化学原理。分别介绍了BPE的极性与驱动电极的关系、BPE体系中的电压及电流的分布,为BPE体系的研究者提供简要的理论基础。此外,还列举了BPE体系在分析检测、材料制备和物质筛选等领域的应用。     

商品检验与分析专业课程体系与教学内容的改革与实践

针对商品检验与分析专业课程体系和教学内容存在的问题,并根据网络调研和实地考察的有关资料,探讨了商品检验与分析专业课程体系设置以及实践环节和教学内容等方面的具体改革措施。     

离子液体在蛋白质萃取分离中的应用

离子液体具有独特的物化性质如热稳定性好、不挥发、不易燃和良好的生物兼容性,近年来作为传统有机溶剂的替代物在有机合成、电化学、催化和萃取分离等领域得到了广泛应用。本文简要综述了以离子液体为媒介的萃取体系在蛋白质分离富集和分析中的相关研究和应用进展,包括辅助萃取体系、直接萃取体系、双水相萃取体系、微乳萃取体系、结晶体系和基于离子液体的固相萃取体系等。     

高中化学课程模块设置的反思及建议

结合普通高中新课程化学学科模块教学的实际情况,分析了现行化学学科模块教学体系中知识体系松散、实验教学弱化以及教科书繁多等主要问题和不足,提出了必修模块重学科基础及知识体系、选修模块重个人爱好和专业发展等改进和优化高中化学学科模块体系的若干建议。     

几种常见纳米材料构建的光学传感体系在生化分析中的应用

近年来生物传感新体系的出现,极大地推动了生物医学、分析、环境等研究领域的发展.由于纳米材料具有一些独特的理化性质,常作为载体材料、信号分子等被广泛应用于构建光学生物传感体系.主要介绍了基于金纳米粒子、石墨烯、碳纳米管、量子点、硅纳米粒子几种常见纳米材料构建的光学传感体系及其在生化分析中的应用.分析讨论了这些体系的原理和实际应用,并展望了其研究和应用前景.     

无机阻燃剂协同阻燃聚合物研究进展

无机阻燃剂协同阻燃体系可降低阻燃剂用量,增强阻燃效果,提高聚合物的耐热性能、加工性能和机械性能,已成为阻燃技术一个重要发展方向。本文综述了无机阻燃剂间的协同阻燃体系在不同聚合物阻燃中的研究进展,对单一阻燃剂和协同阻燃体系的阻燃作用机理、阻燃性能进行了分析总结,着重阐述了铝-镁系和可膨胀石墨等协同阻燃体系,指出各体系的阻燃机理、复配比例、添加量以及协同阻燃效应,并展望了无机阻燃剂协同阻燃体系的发展趋势。     

Pu-H2体系从头算分子动力学的研究

本文应用Gaussian09程序,通过密度泛函理论的相关方法,对钚-氢气体系进行了计算和分析。计算得到了钚与氢气的沿势能剖面的各个特殊点的几何结构。通过约化密度梯度分析方法分析了反应路径中的所有特殊结构的化学键的性质。通过从头算分子动力学的计算,由直接经典轨迹的计算结果得到了反应体系的几何结构、能量随时间的变化,并分析得到体系的大部分能量转化为反应产物的振动能。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.