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31.
Corinne De Dobbeleer 《Tetrahedron letters》2005,46(22):3889-3893
Functionalised medium-ring systems of various sizes can be efficiently prepared by a novel approach that embodies a radical-induced fragmentation of bicyclic β-hydroxy ketones, followed by a second radical-coupling reaction. The unexpected reactivity of α-keto radicals is also discussed. 相似文献
32.
葡聚糖为载体的双亲型LDL吸附剂吸附动力学研究 总被引:3,自引:0,他引:3
合成了以葡聚为载体,同时具有亲水性磺酸基和疏水性胆固醇两类配基的新型低密度脂蛋白(LDL)吸附剂。通过对LDL纯溶液中吸附等温线的测试,比较了以Dextran G-75为载体的双亲型LDL吸附剂与单一亲水型磺酸基配基,单一疏水型胆固醇基吸附剂吸附量和亲和吸附系数的关系。对双亲型LDL吸附剂的吸附动力学进行了初步研究,在LDL溶液中,亲水型磺酸基,疏水型胆固醇配基,双亲型LDL吸附剂对LDL的吸附曲线基本上符合Langmuir吸附方程,另外通过高离子强度NaCl洗脱实验,测定了双亲型LDL吸附剂上具有的磺酸基与胆固醇两类基在对低密脂蛋白吸附过程中所起的配合效果,为下一步作用力机制研究提供了参考依据。 相似文献
33.
ShuXiaCAO JianChenZHANG MingYuNIU KuiLU XinChengLIAO YuFenZHAO 《中国化学快报》2004,15(6):652-654
N-Phosphoryl peptide libraries were constructed by transformation from homo-oligopeptide libraries, which was synthesized by self-assembly of amino acids with the assistance of phosphorus oxychloride. Electrospray ionization mass spectrometry (ESI-MS) was used to monitor the reaction. 相似文献
34.
It is shown that oxazolidines derived from racemic unbranched α-acetoxyaldehydes and ?-ephedrine have predictable chromatographic mobilities, with the R-isomer always having a higher Rf-value. This resolution has been used to prepare and -HETE. 相似文献
35.
36.
The th Department 《有机化学》1985,5(1):107-112
本文评述了当前物理有机化学各个主要领域的研究工作,指出物理有机化学是甚为重要的基础学科,数十年来在深度和广度两方面皆有很大的发展。回顾了我国第一届和第二届物理有机讨论会情况,扼要地介绍了物理有机化学在我国的主要进展。 相似文献
37.
JIANG Hua ZHANG Quanxing CHEN Jinlong Nanjing Electric Power Automation Equipment General Factory The State Power Cooperation of China Nanjing China The State Key Laboratory of Pollution Control & Resources Reuse Dept. of Environme 《Chinese Journal of Reactive Polymers》2002,(1)
1. INTRODUCTION 1,2,4-acid (1-Amino-2-naphthol-4-sulfonic acid) is among the most important naphthalene derivatives which are widely used as the intermediates of dyestuffs. In its production process, however, high strength wastewater streams are gene… 相似文献
38.
39.
Jean-Franjois Nierengarten Andreas Herrmann Rik R. Tykwinski Markus Riittimann Francois Diederich Corinne Boudon Jean-Paul Gisselbrecht Maurice Gross 《Helvetica chimica acta》1997,80(1):293-316
The synthesis of (E)-hex-3-ene-l, 5-diynes and 3-methylidenepenta-1, 4-diynes with pendant methano[60]-fullerene moieties as precursors to C60-substituted poly(triacetylenes) (PTAs, Fig. 1) and expanded radialenes (Fig. 2) is described. The Bingel reaction of diethyl (E)-2, 3-dialkynylbut-2-ene-1, 4-diyl bis(2-bromopropane-dioates) 5 and 6 with two C60 molecules (Scheme 2) afforded the monomeric, silyl-protected PTA precursors 9 and 10 which, however, could not be effectively desilylated (Scheme 4). Also formed during the synthesis of 9 and 10 , as well as during the reaction of C60 with thedesilylated analogue 16 (Scheme 5 ), were the macrocyclic products 11, 12 , and 17 , respectively, resulting from double Bingel addition to one C-sphere. Rigorous analysis revealed that this novel macrocyclization reaction proceeds with complete regio- and diastereoselectivity. The second approach to a suitable PTA monomer attempted N, N′-dicyclohexylcarbodiimide(DCC)-mediated esterification of (E)-2, 3-diethynylbut-2-ene-l, 4-diol ( 18 , Scheme 6) with mono-esterified methanofullerene-dicarboxylic acid 23 ; however, this synthesis yielded only the corresponding decarboxylated methanofullerene-carboxylic ester 27 (Scheme 7). To prevent decarboxylation, a spacer was inserted between the reacting carboxylic-acid moiety and the methane C-atom in carboxymethyl ethyl 1, 2-methano[60]fullerene-61, 61-dicarboxylate ( 28 , Scheme 8), and DCC-mediated esterification with diol 18 afforded PTA monomer 32 in good yield. The formation of a suitable monomeric precursor 38 to C60-substituted expanded radialenes was achieved in 5 steps starting from dihydroxyacetone (Schemes 9 and 10), with the final step consisting of the DCC-mediated esterification of 28 with 2-[1-ethynyl(prop-2-ynylidene)]propane-1, 3-diol ( 33 ). The first mixed C60-C70 fullerene derivative 49 , consisting of two methano[60]fullerenes attached to a methano[70]fullerene, was also prepared and fully characterized (Scheme 13). The Cs-symmetrical hybrid compound was obtained by DCC-mediated esterification of bis[2-(2-hydroxy-ethoxy)ethyl] 1, 2-methano[70]fullerene-71, 71-dicarboxylate ( 46 ) with an excess of the C60-carboxylic acid 28 . The presence of two different fullerenes in the same molecule was reflected by its UV/VIS spectrum, which displayed the characteristic absorption bands of both the C70 and C60 mono-adducts, but at the same time indicated no electronic interaction between the different fullerene moieties. Cyclic voltammetry showed two reversible reduction steps for 49 , and comparison with the corresponding C70 and C60 mono-adducts 46 and 30 indicated that the three fullerenes in the composite fullerene compound behave as independent redox centers. 相似文献
40.
Ravelet C Boulkedid R Ravel A Grosset C Villet A Fize J Peyrin E 《Journal of chromatography. A》2005,1076(1-2):62-70
In this paper, we report for the first time an aptamer-based chiral stationary phase (CSP) able to resolve racemates of both target and various related compounds. The enantiomers of tyrosine and analogues (11 enantiomeric pairs) were separated using an immobilized tyrosine-specific L-RNA aptamer as CSP and an aqueous buffer (8 mM Tris-HCl buffer, 25 mM NaCl, 5 mM MgCl2; pH 7.4) as mobile phase, at a column temperature of 10 degrees C. It appeared that the carboxylic and amino groups as well as the aromatic side chain of amino acid controlled the stereospecific recognition. Modifications on the polar groups were strongly detrimental for enantioselectivity while the replacement of the phenolic group by some bicyclic aromatic residues of different polarity, size or shape did not impair the enantioselective interaction. In addition, the effects of the mobile phase composition and column temperature upon the retention and stereoselective properties of the CSP were assessed. Finally, it was found that the immobilized RNA aptamer could be used under hydro-organic mobile phase conditions without alteration of the stationary phase stability. 相似文献