中环萜类化合物的合成

本文综述了中环萜类化合物的各种合成方法, 它们根据成环方式可以分为四类: 1. 双环或三环化合物的桥键断裂, 2.无环化合物的环合, 3.常规环化合物的环扩大, 4. 大环化合物的环缩小.     

中环萜类化合物的合成

本文综述了中环萜类化合物的各种合成方法,它们根据成环方式可以分为四类:1.双环或三环化合物的桥键断裂,2.无环化合物的环合,3.常规环化合物的环扩大,4.大环化合物的环缩小。     

4-羟基喹啉类化合物的合成研究进展

4-羟基喹啉类[4-hydroxyquinolines或4(1H)quinolones]化合物是一类重要的药物合成中间体,在抗疟、抗癌、抗菌、抗病毒、抗糖尿病等领域发挥重要作用。本文综述了4-羟基喹啉类衍生物的合成方法,包括热环合、碱环合和还原环合等。     

Recent progress in the [5C+1X] annultation of polysubstituted divinyl ketones

六元环化合物是最常见的环状化合物之一,在许多天然产物和具有生物活性的化合物中存在六元环系,因此其合成方法学的研究一直受到化学工作者的重视.在众多合成方法中,[5+1]环合策略作为一种新颖的方法的研究已越来越多,应用得到进一步拓展.结合二乙烯基酮结构特点,就其参与的[5C+1X]成环反应最新进展做一综述.     

多取代二乙烯基酮参与的[5C+1X]环合反应研究进展

六元环化合物是最常见的环状化合物之一,在许多天然产物和具有生物活性的化合物中存在六元环系,因此其合成方法学的研究一直受到化学工作者的重视.在众多合成方法中,[5+1]环合策略作为一种新颖的方法的研究已越来越多,应用得到进一步拓展.结合二乙烯基酮结构特点,就其参与的[5C+1X]成环反应最新进展做一综述.     

喹唑啉稠合螺杂环化合物的合成及晶体结构

许多螺杂环化合物及喹唑啉化合物具有抗癌、消炎、抗真菌、抗细菌、抗结核、抗肿瘤以及除草等生物活性,将噻唑酮和喹唑啉稠合环结构与螺杂环结构合为一体,合成新的喹唑啉稠合螺杂环化合物,以期得到具有更高生物活性的化合物,是当前化学家研究的课题之一,1,3-偶极环加成反应是合成五元杂环的常用方法,采用环外双键结构的化合物为亲偶极体,     

环稠卟啉合成的研究进展

利用卟啉大环的碳架组成及其连带成分进行各种环合反应是构建环稠卟啉分子的有效方法. 基于这一合成策略, 概述了近年来通过卟啉分子的结构修饰完成环稠卟啉合成的最新研究进展.     

大环二萜类化合物的研究——Ⅲ.Cembrene-C的全合成

本文以香叶醇为原料首次成功地合成了天然大环二萜化合物Cembrene-C(1),关键步骤是砜化合物(6)与氯代物(8)的相转移催化偶联反应及低价钛诱导的二羰基化合物(12)的选择性环合反应。     

基于Schiff-Base反应的成环策略及应用

基于Schiff-base反应的大环化合物是近些年来超分子领域研究的热点.这些大环化合物不但在传感器、功能材料等领域发挥着重要的作用,而且在自组装研究领域具有重要的意义.从模板法和非模板法两方面分析了一些具有代表性Schiff-base大环的合成,发现,不但具有合适半径和构型的离子可以作为成环反应的模板,而且强烈的分子内氢键也能有效地驱动成环反应.同时,对于该类大环分子合成所面临的问题及发展方向进行了评述和预测.     

具有抗菌活性的螺环化合物研究进展

综述了近年来具有抗菌活性的螺环化合物的研究进展,详细介绍了部分螺环化合物的合成方法,另外总结出具有抗菌活性的螺环化合物的结构特征.对该类化合物的应用前景进行了展望,提出了一些新的观点.     

Synthesis of azobenzenes: the coloured pieces of molecular materials

Azobenzenes are ubiquitous motifs very important in many areas of science. Azo compounds display crucial properties for important applications, mainly for the chemical industry. Because of their discovery, the main application of aromatic azo compounds has been their use as dyes. These compounds are excellent candidates to function as molecular switches because of their efficient cis-trans isomerization in the presence of appropriate radiation. The classical methods for the synthesis of azo compounds are the azo coupling reaction (coupling of diazonium salts with activated aromatic compounds), the Mills reaction (reaction between aromatic nitroso derivatives and anilines) and the Wallach reaction (transformation of azoxybenzenes into 4-hydroxy substituted azoderivatives in acid media). More recently, other preparative methods have been reported. This critical review covers the various synthetic methods reported on azo compounds with special emphasis on the more recent ones and their mechanistic aspects (170 references).     

Ultrasound Irradiated Synthesis of Bis-pyrimidine Derivative in Aqueous MediA

Pyrimidine derivatives have been found to possess a broad spectrum of biological activities. Among various pyrimidine derivatives, bis-pyrimidine seems to be the rarely studied. A variety of methods have been reported for the preparation of this class of compound. However, in spite of their potential utility, some of the reported methods suffer from drawbacks such as long reaction times, cumbersome product-isolation procedures, and environmental concerns. Organic reactions in aqueous media have attracted increasing interest recently because of environmental issues and the understanding of biochemical processes. Ultrasound has increasingly been used in organic synthesis for greater yields, shorter reaction times or milder conditions.     

Transition metal-catalyzed synthesis and reactivity of N-alkenyl aziridines

[reaction: see text] Straightforward methods for palladium-catalyzed alkenylation of aziridines with alkenyl halides and copper-catalyzed alkenylation of aziridines with alkenyl boronic acids have been developed. This methodology offers attractive alternatives to the known methods requiring activated alkenyl halides and acetylenes. A wide variety of N-alkenyl aziridines containing substituents other than electron-withdrawing substituents such as cyano groups and sulfones have been synthesized in good yields. Furthermore, these N-alkenyl aziridines exhibit quite a different reactivity from conventional enamines, as demonstrated by their reactivity.     

Acoustic methods of detection in gas chromatography

A brief review of the use of acoustic detection methods in GC is presented. While a number of methods (some quite similar) have been developed for use as gas-phase sensors in various applications, this article focuses specifically on those techniques that have been used to detect analytes following their separation by GC. Overall, a number of "active" acoustic methods (which measure analytes through their interaction with a controlled external acoustic wave source) were reportedly used as GC detectors. These include ultrasonic, thickness shear mode, surface acoustic wave (SAW), and flexural plate wave methods. Conversely, "passive" acoustic methods (those that produce an acoustic signal through some chemical reaction with the analyte) have also been used as GC detectors. These include photoacoustic and acoustic flame methods of detection. Of the two major classifications, reports of active methods are far more prevalent. In particular, the usage of SAW techniques with GC is an area of research that has seen accelerated growth in recent years.     

元素化学课堂教学的设计：碳的结构与性能及其应用

以"碳的结构与性能及其应用"为例说明元素化学课堂教学中的方法,引导学生在复习碳元素的结构与性质的基础上,组织学生开展课堂讨论,引导学生对不断涌现的新型碳材料的关注和兴趣。同时,分组讨论碳氧化物的结构与化学性质之间关系及其有效利用,即模拟光合作用实现CO2的光催化还原和基于费托合成实现CO为原料制备燃料,鼓励和推进学生开展碳材料及其应用的本科生科研训练,实现课堂知识与科学研究衔接。     

Are amines basic or nucleophilic catalysts for oxirane ring opening by proton-donating nucleophiles?

The behavior of amines as catalysts for oxirane acidolysis and phenolysis has been studied using kinetic methods. The apparent catalytic and noncatalytic reaction rate constants have been estimated. It has been demonstrated that the noncatalytic pathway has almost no effect on the apparent reaction rate constant. In order to determine the character of the behavior of amines (bases/nucleophiles) in this reaction, their reactivity has been analyzed within the conceptions of basic and nucleophilic mechanisms of catalysis. Based on the quantitative amine structure—catalytic activity correlation, it has been shown by comparing the values of correlation coefficients (r) of equations describing mechanisms for various reaction systems that, in the reactions of oxiranes with proton donors (carboxylic acids and phenols), the catalytic activity of tertiary amines/pyridines is determined by their nucleophilicity rather than basicity.     

New Synthetic Method of trans, trans-Styrylstilbene

Styrylstilbenes and their derivatives are a kind of organic luminescent materials. A variety of synthetic methods have been reported, and their physical properties have been studied. [1,2] A series of para-substituted styrylstilbenes were synthesized by Wittig or Arbusor-Horner reaction as a key step forming C=C bonds.     

XPS and AES investigations of the reaction behaviour of iodine with Zircaloy-4 surfaces

Summary The reaction behaviour of gaseous iodine on Zircaloy-4 surfaces is of interest with regard to the corrosion of fuel cladding tubes in light water reactors. XPS and AES have been employed for its investigation as these methods are most suitable because of their small information depth and their sensitivity to chemical states. It has been shown that the formation of zirconium iodide overlayers reduces further iodine uptake indicating a diffusion-controlled reaction. Further results are discussed in detail.

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XPS- und AES-Untersuchungen zum Reaktionsverhalten von Iod an Zircaloy-4 Oberflächen

     

Reduction of Aromatic Nitro Compounds under Solvent-free Condition Using Almnina-suppored Hydrazine/Fe2 (NO3)3· 9H2O

The application of microwave techniques for chemical synthesis has attracted considerable interest in recent years because of their enhanced selectivity, reduced reaction time, easier work-up procedure. Aromatic amines are widely used as intermediate for dyes, photographic materials, pharmaceutical and agricultural chemicals and as antioxidants. So, particularly intense interest has been directed toward the synthesis of these compounds. Reduction of aromatic nitro compounds is one of the important routes to prepare them. Generally, the processes have been carried out in solvent. [ 1 ～ 6] The drawback of these methods is long reaction time.