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951.
952.
用^3HNMR波谱法分析微波激发催化交换制备的^3H标记颠茄类生物碱 总被引:1,自引:0,他引:1
用~3H NMR波谱法测定了微波激发催化交换制备的四种~3H标记颠茄类生物碱示踪剂的氚标记位置及其相对百分含量。并在用~1H NMK归属原料纯度及标记物分子各基因化学位移时采用了水峰抑制技术(简称WEFT),既能同时消除溶剂氘代甲醇及水峰的影响;又能提高灵敏度(近10倍),从而计算出所得标记产物的化学纯度值与放化纯度值。为快速、准确寻找制备标记生物碱的最佳实验条件和控制标记物质量提供了唯一的物理无损分析方法。 相似文献
953.
A simple and sensitive kinetic method was developed for the determination of ritodrine hydrochloride in pharmaceutical preparations. The method is based upon a kinetic investigation of the oxidation reaction of the drug with alkaline potassium permenganate at room temperature for a fixed 12.5 min; the absorbance of the colored permenganate ion was measured at 609 nm. The absorbance concentration plots were rectilinear over the range of 1.6–11.2 μg mL?1 (r = 0.9992) with a minimum detectability of 0.096 μgmL?1 (2.88 × 10?7 M). The different experimental parameters affecting the development and stability of color were carefully studied and optimized. The determination of ritodrine hydrochloride by the fixed concentration and rate constant methods is also feasible with the calibration equations obtained, but the fixed time method has been found to be more applicable. The proposed method was applied successfully to the determination of ritodrine hydrochloride in tablets and ampoules with average recoveries of 100.37 ± 0.93% and 100.42 ± 0.87%, respectively. The results obtained were in good agreement with those obtained using a reference method for comparison. A proposal of the reaction pathway is also presented. 相似文献
954.
Xiao Ying Xu Feng Cheng Jian Hua Shen Xiao Min Luo Li Li Chen Li Duo Yue Yi Du Fei Ye Shan Hao Jiang Da Yuan Zhu Hua Liang Jiang Kai Xian Chen 《International journal of quantum chemistry》2003,93(6):405-410
Docking simulation of 18 agonists with the ligand binding pocket (LBP) of PPARγ has been performed. The binding conformations and binding affinities of these agonists were obtained by use of the flexible docking protocol FlexX. Test compound calculations indicated that FlexX can reproduce the binding conformation of the crystal structure (root mean square deviation = 1.43 Å); moreover, the predicted binding affinities correlate well with the activities of these agonists. The interaction model and pharmacophore of PPARγ agonists were derived and the difference in biologic activities of these agonists can be well explained. The PPARγ agonists must have both polar head and the hydrophobic tail, which form hydrogen bonds and hydrophobic contacts with hydrophilic and hydrophobic regions of the LBP of PPARγ, respectively. In addition, a suitable linker is also necessary. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 93: 405–410, 2003 相似文献
955.
956.
Yi‐Hang Wen Xia Feng Yin‐Hua He You‐Zhao Lan Hong Sun 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(11):m504-m506
In the title complex, [Zn(C12H6O4)(H2O)]n, a ZnII polymer based on naphthalene‐1,8‐dicarboxylate (1,8‐nap), the ZnII atoms adopt an elongated octahedral coordination geometry. A zigzag chain is formed by μ2‐aqua ligands and μ2‐carboxylate groups of the 1,8‐nap ligands. Adjacent parallel chains are further linked by 1,8‐nap ligands, forming a twisted two‐dimensional layer structure along the (100) plane. 相似文献
957.
Sergio M. Bonesi Maria A. Ponce Rosa Erra‐Balsells 《Journal of heterocyclic chemistry》2004,41(2):161-171
1H and 13C nmr spectra of several N‐ and C‐substituted carbazoles (Series 1, 2, 3 and 4) were measured. Correlations between chemical shifts and substituent constants show that these parameters describe properly the substituent effect on the nmr phenomena. Atomic charge densities for carbazoles of Series 1, 2, 3 and 4 were calculated by using the semi empirical PM3 method. These values also show a linear correlation with the 13C chemical shifts. The synthesis of several carbazole derivatives 1a – 1g, 2a – 2g, 3a – 3j and 4a – 4g have been carried out according to literature procedures. The carbazoles 3i, 3j and 4c have been synthesized and fully characterized for the first time. 相似文献
958.
富镉Hg_(1-x)Cd_xTe是一种新型的光电转换材料,已用于固体结太阳能光伏电池:ITO/CdS/Hg_(1-)Cd_xTe/Au。我们曾对Hg_(1-x)Cd_xTe的电沉积机理作过研究。最近我们用电沉积制备的Hg_(0.09)Cd_(0.91)Te多晶薄膜做成了液体结太阳能光电化学电池并观察到明显光电响应。 相似文献
959.
本文通过无水三氯化希土与等摩尔的甲基环戊二烯基钠(Cp′Na)在四氢呋喃(THF)中反应,合成了八个新的中性甲基环戊二烯基希土二氯化合物Cp′LnCl2·3THF[Ln=Sm(1), Eu(2), Gd(3), Tb(4), Dy(5), Ho(6), Er(7), Y(8)],并研究了茂环上甲基取代基对一茂二氯希土配合物分子结构及稳定性的影响。元素分析、红外光谱和质谱鉴定结果表明这八个化合物都是溶剂化的单体结构,其中配合物7的结构还用单晶X射线分析确证。 相似文献
960.