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51.
Chun‐Li Cao Dr. You‐Yun Zhou Jian Zhou Dr. Xiu‐Li Sun Dr. Yong Tang Prof. Dr. Yu‐Xue Li Dr. Guang‐Yu Li Dr. Jie Sun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(42):11384-11389
Cyclic ketones react with (E)‐2‐nitroallylic acetates in the presence of catalytic pyrrolidine‐thiourea, which affords bicyclic skeletons with four or five stereocenters in one single reaction with up to 98 % ee in moderate to high yields. The cooperative effects of both enamine and the Brønsted acid are found to be crucial for the high reactivity and enantioselectivity of this cascade reaction, which is demonstrated by both theoretical calculation and experimental data. 相似文献
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采用液相合成方法,以很高的纯度和较高的收率合成了3个新的4肽化合物MAG3-Phe-OH,MAG3-Leu-OH和MAG3-Tyr-OH。它们在温和的条件下很容易用99mTc进行标记,并在体内外显示了很高的稳定性。标记物的兔子显象显示新的标记物与99mTc MAG3有不同的代谢途径,有可能对癌细胞有较好的亲合作用而用于肿瘤显像。 相似文献
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Sheng Liu Miao Chen JinDu Li HaoBo Zhang JinQing Wang ShengRong Yang 《中国科学B辑(英文版)》2009,52(7):1009-1013
Hybridization of peptide nucleic acids probe containing azobenzene (NH2-TNT4, N-PNAs) with DNA was performed by covalently immobilizing of NH2-TNT4 in sequence on the 3-mercaptopropionic acid self-assembled monolayer modified gold electrode with the helps of N-(3-dimethylaminopropy1)-N′-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS), and the hybrid was coded as N-PNAs/DNA. Using [Fe(CN)6]4−/3− (1:1) as the electrochemical indicator, the electrochemical properties of the N-PNAs self-assembled monolayer (N-PNAs-SAMs) and N-PNAs/DNA hybridization system under the conditions of before and after UV light irradiation were characterized with cyclic
voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectra (EIS). Results showed that the
redox currents decreased with the increase of irradiation time, suggesting that the ability of the charge transfer on the
electrode surface was weakened and the conformation of hybrid system had been changed, and the control of PNAs/DNA hybridization
could be realized by UV light irradiation.
Supported by the National Natural Science Foundation of China (Grant No. 50572107) and “Top Hundred Talents Program” of Chinese
Academy of Science 相似文献
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Reactions of 2‐isopropoxy‐1, 3, 2‐ benzodioxaborole with equivalent amounts of Schiff base ligands having two hydroxyl groups ( 1a–3a ) yield mononuclear derivatives with one residual hydroxy group. The reactions of these mononuclear derivatives with hexamethyldisilazane in a 2:1 ratio yield heterodinuclear derivatives. All these newly synthesized derivatives have been characterized by elemental analyses and molecular weight measurements. Tentative structures have been proposed on the basis of IR and NMR (1H, 13C, 11B,29Si)spectral data and Fab‐mass studies. Schiff bases and their corresponding mono‐ and heterodinuclear derivatives of boron have also been screened for antifungal activities. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Eva Sjöblom Thomas Edberg Per Stenius 《Journal of Dispersion Science and Technology》2013,34(2):123-145
The phase diagrams for the system TRS 10-80/ butanol/Petrol D/sodium chloride show that the weight ratio B = TRS/butanol is very important for the stability of the microemulsion. R = 1 results in a very limited microemulsion region. Provided the ratio is >1.22 the minimum amount of (TRS+butanol) necessary to form a microemulsion, with equal amounts of water and Petrol D, is 15% and approximately independent of R.However, as R is increased the solubility of water in the (TRS+butanol) mixture is reduced and a liquid crystalline phase is formed. Its presence increases the viscosity and the kinetic stability of the emulsions formed at low content of Petrol D. Addition of electrolyte reduces the minimum amount of (TRS+butanol) necessary to form a microemulsion. Furthermore, systems rich in water separate into two phases; an upper microemulsion phase and a lower aqueous phase. This can be explained in terms of a redistribution of the butanol from the aqueous phase to the oil phase. It is shown that, although the studied system contains unpurified technical products, the phase behaviour is very similar to that of model systems of pure chemicals. X-ray diffraction showed that the liquid crystal line phase was lamellar. The thickness of the amphiphilie layer was 26-28 Å. It is more difficult to obtain direct information of the structure of the microemulsion. However, conductivity data indicated a “bicontinuous” structure or at least, the occurrence of highly dynamic aggregates over a large concentration range. 相似文献