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101.
XU Xing-Youa MA Wei-Xinga GAO Jiana LIU Qing-Liangb a 《结构化学》2002,21(5):473-476
1 INTRODUCTION Macrocyclic ligands and their metal complexes have received much attention due to their applications in ion transport, ion separation and as models in biomimic researches[1~7]. The synthetic methods of macrocyclic ligands and their metal complexes are mainly divided into three kinds[8]. The first one is synthesizing free ligand, then forming the metal complexes; the second is template synthesis; and the third is synthesizing the end-off or side-off precursor ligand, then c… 相似文献
102.
白菜DNA甲基化水平的反相离子对高效液相色谱法研究 总被引:2,自引:0,他引:2
建立了反相离子对液相色谱测定白菜的DNA甲基化水平的方法。采用的色谱柱为HypersilBDSC18柱(200mm×4.0mm,5μm),以pH4.0的甲醇-5mmol·L-1庚烷磺酸钠-三乙胺(10:90:0.2,体积比)的混合液为流动相,UV检测器波长为273nm。通过测定DNA水样所产生的胞嘧啶和甲基胞嘧啶的含量,即可得知DNA甲基化程度。胞嘧啶和甲基胞嘧啶回收率分别为99.6%及103.3%,RSD为3.7%(日内)及5.2%(日间)。 相似文献
103.
A New Asterosaponin from the Starfish Culcita novaeguineae 总被引:1,自引:0,他引:1
HaiFengTANG YangHuaYI LingLI PengSUN DaZhengZHOU BaoShuLIU 《中国化学快报》2005,16(5):619-622
A new asterosaponin named novaeguinoside A, along with a known saponin, asteronyl pentaglycoside sulfate, was isolated from the starfish Culcita novaeguineae. The new compound was identitied to be sodium 6α-O-{β-D-fucopyranosyl-(1→2)-β-D-fucopyranosyl-(1→4)-[β-D-quinovopyranosyl-(1→2)]-β-D-xylopyranosyl-(1→3)-[β-D-quinovopyranosyl}-5α-pregn-9(11)-en-20-one-3β-yl-sulfate by extensive spectral analysis and chemical evidence. 相似文献
104.
α 羟基 α 甲基苯丙酮 (PHMP)是一种性能优良的新型光引发剂 ,具有引发效率高、热稳定性好、耐黄变、无异味等优点[1,2 ] 。现有合成方法步骤多 ,产率低 ,后处理麻烦 ,操作复杂[3,4] ,且在反应过程中会产生HC1或HBr等有毒副产物。本文研究了在相转移催化剂的作用下[5,6 ] ,CCl4直接氯化水解生成α 羟基 α 甲基苯丙酮的新方法。该方法不仅减少了反应步骤 ,简化了操作 ,而且提高了产品质量。1 实验部分1 .1 仪器与试剂傅立叶红外光谱仪Perkin Elmer 1 71 0 ,WXS 1型阿贝折光仪。异丁酸 ,SOCl2 ,苯 ,四氯化… 相似文献
105.
JunZhou Yong-zhiQiu Xiao-pengZang Chang-wangPan QiangChen JianShen Si-congLin 《高分子科学》2005,(1):93-102
N,N-dimethyl-N-methacryloyloxyethyl-N-carboxyethyl ammonium (DMMCA) was graft-copolymerized onto the surface of segmented poly(ether urethane) (SPEU) and PE film. The carboxybetaine structure on SPEU and PE film surfaces was confirmed by ATR-FTIR, XPS and water contact angle measurements. Through the experiments with platelet adhesion and protein adhesion assay in vitro, the two materials studied, including poly-DMMCA gel, all show excellent nonthrombogenicity. This confirms once again that the zwitterionic molecular structure on the surfaces of materials is essential for improving their nonthrombogenicity and biocompatibility. 相似文献
106.
1-substituted-5-benzoylamino-4-pyrazolecarboxamides(2)were prepared by the reaction of 1-substituted pyrazolo[3, 4-d]-oxazinone(1)with amines in benzene.The compound 2 was refluxed with excess LiAlH4 in a mixture of THF and ether, one of the two carbamoyl groups in the molecule 2 was reduced selectively.As the results, 1-substituted-5-benzylamino-4-pyrazolecarboxamides (3) were obtained.Compounds 3reacted with Cl2PPh-X, or P(NET2)3, producing the title compounds(4).The conditions of the reactions were studied. 相似文献
107.
108.
采用高温固相法合成了一种长波紫外激发的SrZnO2∶Eu3+,Li+发光材料,用X射线衍射谱、荧光光谱对样品进行了表征。结果表明,Eu3+离子在SrZnO2基质中主要占据Sr2+离子不对称性格位,发射来源于5D0→7F2612 nm为主的红光。加入电荷补偿剂Li+离子能显著提高发光强度,350~400 nm内的激发峰也有明显提高,同时观察到来自Eu3+离子高能级5D1→7FJ(J=0~2)的跃迁发射,并对其产生机制进行了初步探讨。实验结果表明,SrZnO2∶Eu3+,Li+是一种有发展前途的长波紫外激发红光荧光体。 相似文献
109.
In the present paper, we describe a microfluidics-based sensing system for nonelectroactive anions under negative separation electric field by mounting a single carbon fiber disk working electrode (WE) in the end part of a poly(dimethylsiloxane) microchannel. In contrast to work in a positive separation electric field described in our previous paper (Anal. Chem. 2004, 76, 6902-6907), here the electrochemical reduction reaction at the WE is not coupled with the separation high-voltage (HV) system, whereas the electrochemical oxidation reaction at the WE is coupled with the separation HV system. The electroactive indicator is the carbon fiber WE itself but not dissolved oxygen. This provides a convenient and sensitive means for the determination of nonelectroactive anions by amperometry. The influences of separation voltage, detection potential, and the distance between the WE and the separation channel outlet on the response of the detector have been investigated. The present detection mode is successfully used to electrochemically detect F-, Cl-, SO4(2-), CH3COO-, H2PO4-. Based on the preliminary results, a detection limit of 2 microM and a dynamic range up to three orders of magnitude for Cl- could be achieved. 相似文献
110.
A chiral liquid chromatographic method for determination of the enantiomeric purity of both l-carnitine and acetyl-l-carnitine is described. Separation of the enantiomers of dl-carnitine and acetyl-dl-carnitine was achieved on a commercial chiral column (Chiralcel OD-R) after derivatization with (alpha-bromo)methyl phenyl ketone. Introduction of this lipophilic UV chromophoric group to the carnitine and acetylcarnitine molecules improved their retention, resolution, and UV detection. The mobile phase was 74:26 (v/v) 0.5 mol L-1 sodium perchlorate–acetonitrile, pH 3.8, and the flow rate was 0.4 mL min-1. Detection was performed at 235 nm. The method is selective and reliable for determination of the enantiomeric purity of bulk drug substances l-carnitine and acetyl-l-carnitine. 相似文献