雌甾-4,9-二烯衍生物的A环芳构化反应

研究了11β-羟基或11β-甲氧基雌甾-4,9-二烯衍生物A环芳构化反应, 我们发现在质子溶剂中,酸催化能促进雌甾二烯衍生物转变成雌甾-1,3,5(10),9(11)-四烯.推测反应经过一个雌甾-4,9,11-三烯-3,17-二酮中间体机理. 这一机理通过进一步研究部分得到证实.碘同样可以催化这种芳构化.     

冠醚B15C5萃取分离锂同位素的阴离子效应

本文研究了B15C5冠醚萃取锂盐时,不同阴离子对体系的同位素分离效应的影响。结果表明,阴离子在冠醚萃取过程中不仅对萃取络合物的稳定性有显著影响,而且阴离子半径及软度越大时,萃取体系的锂同位素分离系数(α_(LI))也越大。     

锂盐阴离子和不同侧基的15-冠-5系冠醚对锂盐/冠醚固态配合物远红外位移的影响

按文献的方法研究了锂盐阴离子和不同侧基的15-冠-5系冠醚对四种锂盐/冠醚固态配合物远红外位移的影响.     

7α-甲基-19-羟基-睾丸素-17β-乙酸酯用节杆菌芳构化: 7α-甲基-雌甾酚醇-17β-乙酸酯和7α-甲基-雌甾酚酮的合成

雌甾酚酮(la)和雌甾酚醇(lb)是治疗妇科病的要药。其17位的乙炔衍生物乙炔雌二醇(lc)及其3-甲醚化合物ld是甾体口服避孕药的组分。7α-甲基-雌甾酚酮(le)的生理活性比la大2～3倍,7α-甲基-乙炔雌二醇(lf)的生理活性比lb大20倍。文献报道le或7α-甲基-雌甾酚醇(lg)是由7α-甲基-△~(1,4)-3-酮或7α-甲基-△~4,6-3-酮及其相应的19-失碳甾体化合物经高温或经酸重排等方法制得;也有用节杆菌转化7α-甲基-19-失碳睾丸素而制得。所有这些合成方法不仅步骤多,而且得率往往不佳。本文报道     

17-次乙二氧基-3-甲氧基-雌甾-2,5(10)-二烯-11β-醇用硅胶支持的草酸试剂选择性水解

以3-甲氧基一雌甾-1,3,5(10)-三烯衍生物,经Birch还原所得的3-甲氧基-雌甾-2,5(10)-二烯,是合成各种19-去甲甾体药物的重要前体,在甾体有机合成中有重要意义。在强酸条件下,水解3-甲基烯醇醚,将发生5(10)-双键移位,得到相应的共轭4-烯-3-酮化合物,同时,分子中的其他对酸敏感的基团会     

4′-乙酰基苯并-15-冠-5缩氨基硫脲的微波合成及晶体结构

硫脲衍生物主要通过氢键与阴离子相互作用达到识别的目的，冠醚和硫脲两个主体分子亚单元之间的协同作用往往使冠醚和硫脲表现出对某些客体更加优越的络合识别能力，我们在以前工作的基础上，微波辐射下合成了标题化合物并用红外光谱、核磁共振氢谱、元素分析、X射线单晶衍射对其结构进行了表征，欲进一步研究其对阳离子和阴离子识别的双重功效。     

二苯并-18-冠-6与碱金属苦味酸盐在氯仿中的相互作用

研究一种方法以测定二苯并-18-冠-6在氯仿中与碱金属苦味酸盐相互作用的若干参数。这些参数是:络合物的无限稀释摩尔电导 A_0,络合物的解离常数 K_d(或 k_d),络合物中冠醚与盐的分子比,冠醚对苦味酸盐的络合常数 K_c(或 k_c),以及冠醚存在下苦味酸盐紧密离子对的饱和浓度[MA]等。     

冠醚化合物的合成(ⅩⅤ)——羟基冠醚的合成及其异构体分离

羟基冠醚作为碱金属阳离子的载体显示出极好的性能,它们还可以转化成双冠醚、套索冠醚和具有高络合能力的碳桥三维空间的大环聚醚等许多衍生物,近年来对羟基冠醚及其衍生物的合成和应用研究十分活跃^[1～4]。     

4′,4″-(二苯并-18-冠-6)二甲酸二芳酯的合成和液晶性质

合成含冠醚结构单元而又具有液晶结构特征的化合物,可能获得兼有冠醚络合性能和液晶特性的新型材料,因而在理论上和应用上都有很好的前景。近年已有几例冠醚衍生物液晶的报道。     

合成聚合物在手性分离中的应用进展

介绍了合成聚合物在手性分离中的应用,合成聚合物包括：包含有环糊精的聚合物、包含有冠醚的聚合物、聚丙烯酰胺衍生物、聚甲基丙烯酸酯衍生物、聚表面活性剂等。共引用文献44篇。     

饱和漆酚冠醚聚合物的研究

<正> 冠醚具有选择性络合阳离子的能力,引起了人们极大的兴趣。高分子冠醚或冠醚高分子固定化,从应用角度考虑,不仅毒性降低,而且易于回收和反复使用,这是扩大冠醚应用范围的一个重要途径,也是研究冠醚化学的新动向,smid等对冠醚高聚物的合成和络合性能的研究已有报道。Blasius等将二苯并18-冠-6与甲醛或与苯酚及甲醛缩聚,得到冠醚高聚物可作为离子交换剂。     

Perfluoroalkylation of benzo crown ethers with sodium perfluoroalkanesulfinates in the presence of oxidant

Using Ce(SO4)2 or Mn(OAc)3 as oxidant, dibenzo crown ethers such as dibenzo-18-crown-6 (1) and dibenzo-24-crown-8 (5) and benzo-12-crown-4 (7) reacted smoothly with sodium perfluoroalkanesulfinates (2a-2e) to give the corresponding perfluoroalkylated products (3,4,6,7) in good yields with two isomers obtained in the case of dibenzo crown ethers. This provides a facile synthesis of perfluoroalkyl-containing crown ethers.     

The role of crown ethers in drug delivery

The unique structure of the crown ethers has attracted the attention of many scientists to the use of these compounds in organic synthesis, and drug delivery. In recent years, extensive research has been conducted on the use of crown ethers in the drug delivery process. In the drug delivery process, the use of compounds that can act selectively is very important. Crown ethers with their unique structure can appear in various roles in drug delivery. In recent years, the use of crown ethers in the formulation of nano-drugs have attracted the attention of many researchers, and it shows that crown ethers have a great potential in the process of drug delivery. In fact, chemistry plays a role as a medium for transferring information from suitable compounds to drug delivery. Reviewing the results of the research provides the opportunity to create new ideas for using crown ether in new drug delivery systems.     

Magnetic nanoparticle-supported crown ethers

Magnetic nanoparticle (MNP)-supported crown ethers were successfully prepared and evaluated as catalysts for solid-liquid phase-transfer reactions; the catalytic activities of the MNP-supported crown ethers were not inferior to those of non-supported crown ethers; after the reactions, the catalysts could be readily separated using an external magnet and reused without significant loss of catalytic efficiency.     

网状聚合物冠醚的合成与性能—Ⅰ.以双环氧丙基醚、乙二醇双环氧丙基醚及多缩乙二醇双环氧丙基醚为原料合成

本文报道了一类新型网状聚合物冠醚的合成方法及其性能。分别通过双环氧丙基醚、乙二醇双环氧丙基醚及多缩乙二醇双环氧丙基醚等五种双环氧单体的网化聚合,直接合成了八种网状聚合物冠醚。聚合反应中分别采用了两种催化体系:BF₃·OEt₂和(i-Bu)₃Al。测定了网状聚合物冠醚对金属阳离子的络合容量及其在亲核取代反应中的相转移催化活性。实验表明,这类网状聚合物冠醚合成简便、性能良好且便于重复使用。     

Complex Formation of Crown Ethers with the Cucurbit[6]uril–Spermidine and Cucurbit[6]uril–Spermine Complex in Aqueous Solution

Alkyl amines are able to form complexes with either crown ethers or cyclodextrins or cucurbit[6]uril. The same is known for polyamines such as spermidine and spermine. However, the simultaneous formation of such polyamines with crown ethers and cucurbit[6]uril has not been studied. The ability of polyamines such as spermidine and spermine to form mixed complexes with different ligands, e.g. crown ethers and cucurbit[6]uril has been studied in aqueous solution using pH-metric and calorimetric titrations. The thermodynamic data of reaction between crown ethers with spermidine, spermine and their cucurbit[6]uril complexes have been determined. The presence of cucurbit[6]uril on the polyamines has no important influence upon the reaction of these amines with crown ethers. The reactions between polyamines, cucurbit[6]uril and crown ethers are simple examples for the self organization of molecules due to specific interactions. Received in final form: 26 January 2005     

Regioselective synthesis of syn disubstituted dibenzo-30-crown-10 ethers

A practical and regioselective synthetic method for the synthesis of syn substituted dibenzo-30-crown-10 ethers is reported. This novel methodology is reported with the syntheses of dibenzo crown ethers bearing nitro, formyl and carbomethoxy groups. The synthesis of macrocyclization precursors was accomplished in three steps and featured an application of para-methoxybenzyl group (PMB) as protecting group of phenol moiety that is orthogonal to NO₂, CHO and COOMe groups. General non-high dilution macrocyclization conditions have been developed that allow for the effective preparation of substituted large crown ethers.     

有机磷化合物的研究XIX.III亚磷酸二烷基酯钠的相转移催化P-烷基化反应

Sodium dialkyl phosphite reacts with non-activated alkyl halide in the presence of crown ether to give dialkyl alkyl phosphonate in moderate yield. Little or no reaction takes place in the absence of crown ether under the same conditions. In all cases, crown ether was present in catalytic amts. indicating that it behaves as a phase transfer catalyst between solid and liquid phases. The influences of structures of crown ethers, alkyl halides, dialkyl phosphites and the nature of solvent on the P-alkylation of sodium dialkyl phosphite have been investigated.     

Twenty-five Years of "Crowning" Around: Synthesis of Crown Ethers at Brigham Young University

A review of the synthesis of crown ethers at Brigham Young University ispresented. Topics include: thiacrown ethers, diestercrown ethers,proton-ionizable crown ethers, chiral crown ethers, azacrown ethers,cryptands and other polycyclic ligands, and the Mannich reaction method toprepare azacrown ethers and cryptands.     

Templated synthesis of desymmetrized [2]catenanes with excellent translational selectivity

Desymmetrized [2]catenanes were synthesized and shown to exhibit excellent translational selectivity. The templated synthesis takes effect from the formation of pseudorotaxanes between pi-rich crown ethers and a pi-deficient pyromellitic (PmI) unit, followed by macrocyclization around the crown ethers with the creation of a bipyridinium (BPy) unit. The crown ethers preferably encircle the BPy unit in the resulting [2]catenanes in both solution and the solid state, as indicated by various spectroscopic analyses.