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1.
2-F氯-1-苯基乙醇和2-溴-1-苯基乙醇对映体的高效液相色谱分离阮源萍高景星黄培强②(厦门大学化学系材料和生命过程分析科学国家教委开放研究实验室厦门361005)2-卤-1-苯基乙醇对映体是合成许多手性药物的重要中间体,不对称合成是制备这类化合物...  相似文献   

2.
采用高效毛细管电泳,以羧甲基-β-环糊精、羟丙基-β-环糊精、二甲基-β-环糊精作为手性添加剂对氯霉素前体和甲砜霉素前体对映体进行了分离。并研究了手性选择剂的类型和浓度、背景电解质的酸度、背景电解质的类型、操作电压和温度等因素对对映体分离的影响。分离结果表明,不仅为此类药物提供了简便、快速的分离分析方法,而且还获得了比以往报道更高的分离度。  相似文献   

3.
文章以环糊精及其衍生物为手性试剂,研究了血管扩张型降压药盐酸尼卡地平、尼莫地平和尼群地平手性对映体拆分方法.采用区带毛细管电泳模式,以高磺化环糊精(HS-CD)为手性识别试剂,考察了手性试剂的类型、浓度及缓冲溶液pH值等对分离度的影响,确定了拆分尼卡地平、尼莫地平和尼群地平手性对映体的最佳条件.结果表明盐酸尼卡地平在HS-γ-CD手性选择剂存在下对映体获得基线分离,尼莫地平和尼群地平分别在HS-β-CD和HS-α-CD手性选择剂存在下对映体获得部分分离,并对其分离机理进行了初步探讨.  相似文献   

4.
用高效毛细管电泳法研究山莨菪碱的手性分离   总被引:1,自引:1,他引:0  
目的研究山莨菪碱的手性分离.方法以β-环糊精及羧甲基-环糊精为手性选择剂,用高效毛细管电泳法对影响手性分离的主要因素进行研究.结果建立了拆分山莨菪碱对映异构体的最佳分离体系.结论羧甲基-环糊精可使山莨菪碱的4种对映异构体达到基线分离,与山莨菪碱结构相似的东莨菪碱和阿托品未达到手性分离.  相似文献   

5.
用双-(6-氧-间羧基苯磺酰基)-β-环糊精作为手性选择剂,制备了手性HPCE整体柱,采用正向高效毛细管电泳法(HPCE)拆分了非衍生化的D,L-苯丙氨酸(D,L-phenylalanine),考察了缓冲液浓度、pH值、分离电压等因素对苯丙氨酸对映体保留特性和分离度的影响,探究了分离的最佳条件.结果表明:在最佳条件下,对映体分离度达到4.46,建立了一种高效的苯丙氨酸两对映体分离分析的新方法.  相似文献   

6.
利用不同手性固定相对DL—氨基酸衍生物对映体手性分离   总被引:1,自引:0,他引:1  
利用三种手性固定相对6种N-乙酰化DL-氨基酸酯进行了手性分离研究,结果表明,N-乙酰化DL-氨基酸酯的手性分离系数α随氨基酸手性中心基团R1和衍生化基团R2的增大而增大,同时CSP具有手性识别的手性中心基团空间位阻的增大也有利于改善手性分离效果,对映体的馏出顺序取决于CSP具有手性识别的手性中心的构型,本文还为已提出的N-乙酰化DL-氨基酸酯在该类手性固定相上的手性分离机理进行了补充。  相似文献   

7.
评述了近年来毛细管电泳手性分离的进展。以各种手性选择剂的发展为线索介绍了毛细管电泳手性分离理论、方法及应用。简要说明了分离中应注意的一些关键问题。  相似文献   

8.
利用三种手性固定相对6种N-乙酰化DL-氨基酸酯进行了手性分离研究,结果表明:N-乙酰化DL-氨基酸酯的手性分离系数α随氨基酸手性中心基团R1和衍生化基团R2的增大而增大,同时CSP具有手性识别的手性中心基团空间位阻的增大也有利于改善手性分离效果,对映体的馏出顺序取决于CSP具有手性识别的手性中心的构型,本文还为已提出的N-乙酰化DL-氨基酸酯在该类手性固定相上的手性分离机理进行了补充.  相似文献   

9.
手性化合物的生物活性与制取方法   总被引:2,自引:0,他引:2  
介绍了各种对映体化合物不同的生物活性以及它们在医药、农药化学品、香料香精方面所起的作用,评述了目前制备手性化合物的方法。讨论了毛细管电泳法拆分对映体的四种模式及手性催化合成法,展望了手性催化合成法的前景。  相似文献   

10.
高效毛细管电泳是进行手性异构体拆分的常规仪器,也是药学专业的学生必须掌握的大型仪器之一。通过设计药学案例介绍了高效毛细管电泳的分离模式、影响分离的因素及手性分离策略,探索了pH值、手性添加剂的浓度及手性添加剂的种类对佐匹克隆对映体分离的影响。该实验引入了新仪器,增加了学生的实验兴趣,锻炼了学生的科研思维能力,该实验可以在本科药学专业仪器分析实验中推广使用。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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