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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. 相似文献
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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. 相似文献
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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 相似文献
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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]。 相似文献
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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。 相似文献
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HUANG Wei-Yuan LIU Jin-TaoShanghai Institute of Organic Chemistry Chinese Academy of Sciences Fenglin Lu Shanghai China 《中国化学》1994,12(3):283-288
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. 相似文献
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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. 相似文献
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Magnetic nanoparticle-supported crown ethers 总被引:1,自引:0,他引:1
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. 相似文献
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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 总被引:7,自引:2,他引:5
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。 相似文献
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Hans-jürgen Buschmann Lucia Mutihac Eckhard Schollmeyer 《Journal of inclusion phenomena and macrocyclic chemistry》2005,53(1-2):85-88
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 相似文献
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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. 相似文献
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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. 相似文献
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Jerald S. Bradshaw 《Journal of inclusion phenomena and macrocyclic chemistry》1997,29(3-4):221-246
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. 相似文献
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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. 相似文献