两种二苯醚类除草剂在直链淀粉液相色谱手性固定相上的拆分

以硅胶涂敷直链淀粉-三(5-氯-2-甲基苯基氨基甲酸酯)为手性固定相,对两种含有1个手性中心的二苯醚类除草剂2-甲氧基-2-{5-[2-氯-4-(三氟甲基)苯氧基]-2-硝基苯)丙酸甲酯和乳氟禾草灵,进行了色谱分离.考察了流动相中异丙醇和正己烷的体积比对乳氟禾草灵对映体分离的影响.结果显示,这2种二苯醚类除草剂可以同时在Chiralpak AY-H色谱柱上获得较好的手性拆分结果；并对农药对映体与固定相之间的保留机理进行了讨论.     

改性血红蛋白诱导手性聚苯胺的合成（英文）

本文首次研究了改性血红蛋白诱导的手性聚苯胺的合成.研究结果显示血红蛋白在经历拆分、失活和包埋后能够成功地诱导手性聚苯胺的产生,意味着血红蛋白可以在任何苛刻的反应体系中作为手性诱导剂使用.通过对改性血红蛋白诱导合成的手性聚苯胺的性质进行研究后发现,失活血红蛋白诱导合成的手性聚苯胺具有良好的手性、稳定性和晶形结构.从血红蛋白中拆分得到的珠蛋白能够诱导手性聚苯胺的产生,但是拆分得到的血红素部分不能诱导手性聚苯胺的合成.研究结果还表明,包埋的血红蛋白诱导合成的手性聚苯胺的产率、搀杂状态和晶形结构都比较差,说明相比较之下包埋对于血红蛋白诱导合成手性聚苯胺是不利的.研究结果证明血红蛋白的结构对于手性聚苯胺的形貌有重要影响.     

手性固定相NP-HPLC拆分达非那新中间体对映体

采用多糖衍生物手性色谱柱,建立了正相高效液相色谱法(NP-HPLC)拆分达非那新中间体对映体.考察了该对映体在不同手性固定相上的分离趋势及保留顺序,以及流动相组成对该中间体对映体的分离度和洗脱顺序的影响.结果表明:用Chiralpak AD和Chiralcel OJ柱均能实现对映体的有效分离,为达非那新中间体的光学纯度...     

环糊精及其衍生物在手性药物分离中的应用

手性药物的对映体由于空间结构不同,在生物体内结合的受体不同,导致其在药理和药效上有很大的差异,因此对手性药物进行手性拆分分析研究有着非常重要的现实意义.本文综述了2000年来环糊精及其衍生物作为手性流动相添加剂在高效液相色谱法中分离手性药物的应用情况.     

R-(+)-α-苯乙胺基草酰肼的拉曼光谱研究

酰肼类的衍生物是制备光学纯螺二酮的一种重要手性拆分剂, 因此, 对酰肼类衍生物结构研究就显得尤为重要。在本文中我们对手性拆分剂R-(+)-α-苯乙胺基草酰肼进行了拉曼光谱测试分析, 并对主要的谱峰进行了归属, 进一步证实了它的结构。     

(2R,5S)-N-间氟苄基-2,5-二甲基哌嗪的合成

以(2R,5S)-2,5-二甲基哌嗪为原料,经过成盐,单取代反应,用D-酉石酸对光学异构体的手性拆分,用氢氧化钠游离,最终合成(2R,5S)-N-间氟苄基-2,5-二甲基哌嗪,反应总收率为83％.该物质的合成未见文献报道,目标化合物用1H NMR,IR进行结构表征.     

孤立条件下布洛芬分子手性转变过程的理论研究

基于密度泛函理论的B3LYP方法,采用6-31+g(d,p)基组,对孤立条件下布洛芬分子的手性转变过程进行研究.通过寻找反应过程中包括过渡态和中间体的各极值点结构,绘制了布洛芬分子手性转变路径反应势能面,分析了各极值点的几何和电子结构特性.结果表明:布洛芬实现从S型到R型手性转变的反应路径有两条.路径1包括三个过渡态和两个中间体,路径2包括四个过渡态和三个中间体.反应路径上最大的能垒是73.54 Kcal/mol,来源于手性碳上的氢向羧基上的氧转移.这一研究为进一步实现一些有重要应用价值的点手性分子手性转变反应调控提供了理论参考.     

柱前衍生化RP-HPLC拆分盐酸洛美沙星对映异构体

以2,3,4,6-乙酰基-β-D-吡喃葡萄糖基异硫氰酸酯(GITC)为柱前衍生化试剂,建立了盐酸洛美沙星对映体柱前衍生化RP-HPLC拆分方法。采用了C18(4.6×250mm,5μm,Bnentnach)为色谱柱,在流动相为甲醇∶(3mmol.L-1四丁基溴化铵水溶液∶5mmol.L-1Na2HPO4的水溶液=1∶2)=25∶75,流速为1mL·min-1,检测波长284nm的色谱条件下,盐酸洛美沙星的非对映体在1.0—27.5μg.mL-1的浓度范围内有良好的线性关系,日内、日间精密度都3%,且获得了基线分离。该种方法能用于盐酸洛美沙星的手性拆分,也为盐酸洛美沙星的光学异构体的测定提供了参考。     

密度泛函理论研究具有手性侧链的卟啉液晶分子几何结构与电子光谱

采用量子化学密度泛函理论方法在B3LYP/6-31G水平上对具有手性侧链的卟啉液晶分子进行几何结构优化,在此基础上使用含时密度泛函理论方法计算了分子第一激发态的电子垂直跃迁能,得到最大吸收波长λmax.计算表明,手性侧链取代基对λmax的影响不大,Zn络合导致最大吸收波长兰移,与实验结果一致.     

手性固定相正相高效液相色谱法拆分普萘洛尔对映体

建立了手性固定相正相高效液相色谱拆分普萘洛尔对映体的方法,考察普萘洛尔对映体在4种多糖类手性色谱柱(Chiralpak AD柱、Chiralcel OD柱、Cniralcel OJ柱和Chiralpak AS柱)(Daicel,250mm×4.6mm,10μm)上的分离行为,同时考察了流动相中醇类以及碱性添加剂二乙胺(...     

Chiral electric field in relativistic heavy-ion collisions at energies available at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider

It has been proposed that electric fields may lead to chiral separation in quark-gluon plasma(QGP).This is called the chiral electric separation effect.The strong electromagnetic field and the QCD vacuum can both be completely produced in off-central nuclear-nuclear collision.We use the Woods-Saxon nucleon distribution to calculate the electric field distributions of off-central collisions.The chiral electric field spatial distribution at Relativistic Heavy-Ion Collider(RHIC) and Large Hadron Collider(LHC) energy regions are systematically studied in this paper.The dependence of the electric field produced by the thermal quark in the central position with different impact parameters on the proper time with different collision energies in the RHIC and LHC energy regions are studied in this paper.     

Two-dimensional model for mixtures of enantiomers,bent hard needles: a Monte Carlo simulation

We study the statistical mechanical conditions under which segregation of racemic mixtures of chiral molecules is possible in a two-dimensional fluid model. Motivated by experimental evidence indicating that chiral hydrophilic heads of amphiphilic molecules lying in a monolayer can crystallize undergoing a chiral phase separation, we propose a two-dimensional system to model the projection of the chiral head of amphiphilic molecules in a monolayer. The molecules of our model are infinitely hard and infinitely thin. We consider interactions with only a repulsive contribution where molecules have no effective area (two-dimensional volume). As a consequence all effects found are due to excluded area. The Monte Carlo Gibbs ensemble is used to study phase separation whereas constant pressure simulations are performed to obtain equations of state of pure and racemic systems. We find that for this simple model segregation is generally possible in the very high density regime.     

高效液相手性固定相法分离分析几个质子泵抑制剂对映体

建立了高效液相手性固定相法分离分析几个质子泵抑制剂对映体的方法。使用CHIRALCEL OD-RH色谱柱,考察了有机改性剂的种类和比例、pH、流速和柱温等因素对对映体分离分析的影响,并探讨了其分离机理。雷贝拉唑和兰索拉唑对映体可实现完全分离,泮托拉唑、奥美拉唑和泰妥拉唑可达到部分分离。     

Chiral crossover transition in a finite volume

Finite volume effects on the chiral crossover transition of strong interactions at finite temperature are studied by solving the quark gap equation within a cubic volume of finite size L. With the anti-periodic boundary condition, our calculation shows the chiral quark condensate, which characterizes the strength of dynamical chiral symmetry breaking, decreases as L decreases below 2.5 fm. We further study the finite volume effects on the pseudotransition temperature T_c of the crossover, showing a significant decrease in T_c as L decreases below 3 fm.     

Two-dimensional chiral segregation of the bent hard needles model with Lennard-Jones sites

Assuming the aggregates of a single chiral component as a pure phase, chiral segregation can be considered as a coexistence of two phases, therefore the formalisms of phase transitions in Statistical Mechanics can be applied. That is, chiral segregation can be considered as phase equilibrium. The standard mechanism to understand phase equilibrium considers the complete van der Waals forces, including repulsions and attractions. However, during the last few years, a particular kind of fluid-fluid equilibrium, explained in terms of only excluded volume effects, has gained important interest. This kind of phenomenon is known as depletion forces. In this paper, the contribution of these two mechanisms is investigated. In order to analyze the effect that repulsions and attractions have on chiral segregation we study a two-dimensional model, bent hard needles model. In one case only infinitely repulsive interactions are considered while in the second case, one and two Lennard-Jones (LJ) sites are added to model the complete van der Waals forces. In the first case, because of the nature of the model, the cause for chiral segregation is due to excluded volume effects that appear when the density of the system is sufficiently high. In the second case, the model proposed is more complex and besides the density the temperature also affects the phase separation. Monte Carlo simulations in the Gibbs ensemble (GMC) are used to perform this comparison. As a result, the segregation phase diagram is obtained for the infinitely repulsive model and that with two LJ sites. The important conclusions are that for some particular molecular geometries, repulsions are not able to produce chiral segregation at all, independently of density. However, when attractions are included the effect of repulsion is complemented and phase separation can be achieved even for those molecular geometries where infinitely repulsions were not able.     

表面压诱导的外消旋双亲分子单层手征相分离的数学模型及其二维古典解

研究表面压诱导的外消旋双亲分子单层手征相分离问题，通过视双亲分子单层为混合胆甾液晶薄膜、应用自由能极小化法所建立的数学模型，进而求出手性分离序参数与分子排列图案所满足的平衡方程的几类二维古典解. 关键词：     

One-Dimensional World as a Tool to Study Chiral Effects

JETP Letters - An analog of the chiral separation effect and the chiral magnetic effect has been studied for fermions in one spatial dimension. The relation of these effects to axial anomaly in the...     

Optical rectification on a surface of isotropic chiral thin film

In this study, the optical rectification (OR) effect on a surface of the isotropic thin film which consists of chiral molecules that base on a one-electron-on-helix model and a two-coupled-oscillator (Kuhn) model have been investigated by us separately. The expressions of dc electric polarization on the isotropic chiral thin film surface and the relations between the OR and microscopic parameters of chiral molecular configuration have been obtained by theoretical derivation. Furthermore, the relations of dc electric polarization with the wavelength of incident light and microscopic parameters of chiral molecular configuration have been simulated numerically. We find the fact that the OR on the isotropic chiral thin film surface is influenced by microscopic parameters of chiral molecular configuration. As well, compared with chiral molecules based on a two-coupled-oscillator Kuhn model, which are based on a one-electron-on-helix model are more suitable for the OR from the point of the influences of molecular microscopic parameters on the OR. The influences of molecular microscopic parameters on the OR might aid in providing some insights into designing and synthesizing new better nonlinear chiral material.