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991.
ShuJieHOU ChuanChunZOU PingShengLEI DeQuanYU 《中国化学快报》2004,15(7):781-784
Two protected tigogenyl glycosides were synthesized via parallel synthesis of oligosaccharide. Using chemical synthesis and conformational analysis the reason of the proton signal of 2“ acetyl group shifted up field in ^1H-NMR was discussed. 相似文献
992.
(R)-N-乙酰四氢噻唑-2-硫酮-4-羧酸与醇反应,在SOCl2存在下得到乙酸酯及四氢噻唑-2-硫酮-4-羧酸酯;在碳酸钾存在下得到乙酸酯及四氢噻唑-2-硫酮-4-羧酸;在二环己基碳二亚胺(DCC)存在下得到缩水产物N-乙酰四氢噻唑-2-硫酮-4-羧酸酯。 相似文献
993.
994.
Alkyl glucoside 1 and aryl glycosides 2-4 were highly stereospecifically synthesized over 4-6 steps from commercially available starting materials. The coupling reaction of the acetobromo-α-D-glucose with the unprotective dihydroxy aglycon in the presence of silver oxide, or with aromatic aglycon in the presence of sodium hydroxide produced the key intermediate. Only β-configuration glycosides were formed in this procedure. The synthesis of all these glycosides was reported for the first time. 相似文献
995.
Mass spectroscopic characteristics of phosphoryl amino acids were studied in detail by positive and negative electrospray ionization mass spectrometry (ESI-MS) in conjunction with tandem mass spectrometry (MS/MS). Besides N-diisopropyloxyphosphoryl amino acids (N-DIPP-AA), O-phospho- and O-diisopropyloxyphosphoryl amino acids (O-DIPP-AA) were studied and compared to N-DIPP-AA. The fragmentation pathways of [M H]^ ,[M Na]^ and [M-H]^- ions of phosphoryl amino acids were summarized. In addition to several similar patterns, each of them showed its characteristic fragmention. 相似文献
996.
研究了酚醛型吸附树脂JDW 2在非水体系中对吡啶和N ,N 二甲基苯胺的静态吸附 .由实验结果推论正己烷中树脂对吡啶和N ,N 二甲基苯胺的吸附是以氢键吸附机理为主进行的 ,JDW 2酚醛型吸附树脂在正己烷中 ,等温吸附吡啶和N ,N 二甲基苯胺的平衡吸附数据符合Langmuir方程 ,相关系数在 0 99以上 ,因此 ,酚醛型吸附树脂在正己烷中吸附吡啶和N ,N 二甲基苯胺属单分子层吸附 ;同时对非水体系中乙醇或乙酸乙酯的含量对树脂吸附吡啶和N ,N 二甲基苯胺的影响进行了研究 相似文献
997.
The crystal structure of the title compound (C27H38N4O7S3, Mr = 626.79) has been determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group Pīwith a = 9.411(1), b = 11.645(2), c = 14.672(2) (A。), α = 91.80(1), β = 95.36(1), γ =104.56(1)o, V = 1547.0 (A。)3, Z = 2, Dc = 1.346 g/cm3, λ = 0.71073 (A。), μ(MoKα) = 0.289 mm-1 and F(000) = 664. The structure was refined to R = 0.0406 and wR = 0.1177 for 4103 observed reflections with I > 2σ(I). X-ray diffraction analysis reveals that the title compound is a practically distorted tetrahedron and each molecule contains one lattice H2O by hydrogen bond. The antitumor activity of the title compound against HL-60 human leukemia cells has also been studied by MTT method. 相似文献
998.
Qing MU Yue E FANG 《中国化学快报》2006,17(9):1236-1238
A novel thermo-sensitive switching membrane has been prepared by radiation-induced simultaneous grafting N-isopropylacrylamide (NIPAAm) onto chitosan membrane. Fourier transform infrared spectroscopy (FTIR) was used to identify the structure of the grafted membranes. The surface morphology of the grafted membrane was observed from scanning electron microscopy (SEM). Pure water flux measurements showed that water flux of the grafted membrane decreased with the increase of temperature, while that of chitosan membrane was constant. It was proved that grafted membrane was sensitive to temperature. 相似文献
999.
The thermal behavior and kinetic parameters of the exothermic decomposition reaction of N‐N‐bis[N‐(2,2,2‐tri‐nitroethyl)‐N‐nitro]ethylenediamine in a temperature‐programmed mode have been investigated by means of differential scanning calorimetry (DSC). The results show that kinetic model function in differential form, apparent activation energy Ea and pre‐exponential factor A of this reaction are 3(1 ‐α)2/3, 203.67 kJ·mol?1 and 1020.61s?1, respectively. The critical temperature of thermal explosion of the compound is 182.2 °C. The values of ΔS≠ ΔH≠ and ΔG≠ of this reaction are 143.3 J·mol?1·K?1, 199.5 kJ·mol?1 and 135.5 kJ·mol?1, respectively. 相似文献
1000.
1 INTRODUCTION 4-Acyl-5-pyrazolone, a family of flexible b- diketonate, is widely used as extract[1] and well known for its applications as analgesics, antipyre- tics, anti-inflammatory and insecticides[2]. Therefore the study on the derivation of 4-acyl-5-pyrazolone is the focus of many research groups working in the fields of coordination chemistry, biomedicine and pharmaceutical chemistry. In order to study the rela- tionship between the structure and performance of these compounds, w… 相似文献