对映的

We studied effects of additives in the allylic amination reaction. We found that4NF could improve the reactivity and enantioselectivity.

对于烯丙基胺化反应，我们研究了外加添加剂对对映选择性的影响，我们发现四丁基氟化铵的加入可以大大提高反应速度及对映选择性。

These dendritic NOBIN derived Schiff base ligands have been applied to titanium catalyzed hetero-Diels-Alder reaction of Danishefshy's diene and aldehydes, affording the corresponding 2-substituted 2, 3-dihydro-4H-pyran-4-one in quantitative yields and excellent enantioselectivities (up to 97. 2%ee). Comparing the reactivities and enantioselectivities of reaction catalyzed by the titanium complexes of these Schiff base ligands, it was found that a series of ligands L〓 were superior to the other three series of ligands L〓, L〓 and L〓, a significant positive NLE and a dendrimer effect existed in the L〓 dendritic catalyst system. The disposition of the dendritic wedges and the dendron size in the ligands were observed to have a significant impact on the enantioselectivity of the reaction.

NOBIN衍生的树枝状大分子希夫碱手性配体与钛形成的配合物在催化不对称杂Diels-Alder反应中的应用将得到的四个系列NOBIN衍生的树枝状希夫碱三齿手性配体与四异丙氧基钛形成的配合物用于催化Danishefsky's diene与醛的不对称杂Diels-Alder反应，通过反应条件的优化，获得了定量的收率和最高达97.2％ee值的对映选择性；考察了这四个系列NOBIN衍生的树枝状希夫碱钛配合物的催化活性和对映选择性，结果发现它们的活性次序依次为L〓≈L〓＞L〓＞L〓，对映选择性次序依次为L〓＞L〓＞L〓＞L〓。

The enantiomer that rotates the plane to the right is referred to as the dextrorotatory.

使平面向右旋转的对映体，称为右旋对映体。

The results show that tetraphenylborate lipophilic anion and terbutaline enantiomorph form two lipophilic salt complexes, which facilitates the solubilization of the enantiomorph in the organic phase.

实验表明，BPh4与特布他林对映体形成2种疏水性复合盐，促进对映体在有机溶剂中的溶解。

Results: Under the experimental conditions adopted, the baseline separation of ephedrin and ephedrine levorotatory was obtained.

结果：麻黄碱及伪麻黄碱对映体得到良好分离，并满足进行左旋麻黄碱中对映异构体杂质检查所需要的条件。

However, color images transforming between different devices require an appropriate color mapping for displaying colors, and the first step of color mapping is the construction of color volume boundary of device.

然而色彩影像在不同媒介间之转换须适当地将色彩对映出正确的色彩，建立显示媒介之色域空间为色彩对映的第一步。

Objective To develop a RP-HPLC method for the enantiomeric separation of indapamide on a new chiral column CHIRALCEL OD-RHcellulose tris(3,5-dimethylphenylcarbamatecoated on a5μm silica-gel substratefor pharmaceutical study of indapamide.Methods To obtain optimistic method for the enantiomeric separation of indapamide,the inferences of the composition of mobile phase,the flow rate and the temperature on the enantiomer retentivity and selectivity were examined and discussed.

目的采 用新型反相手性色谱柱CHIRALCEL OD-RH(纤维素3，5-二甲基苯基氨基甲酸酯涂敷在5μm硅胶上)，建立吲达帕胺对映体的反相高效液相色谱拆分方法，为研究吲达帕胺手性对映体药代动力学提供基础。

The E-TOF will also be feasible and practical to assist chemists in screening the optimal reaction condition or evaluating the overall efficiency of different catalytic systems for a specific asymmetric reaction.4.For the first time,we explored chiralγ-hydroxy-α,β-acetylenic esters,which were prepared via asymmetric alkynylation,as key intermediates to the synthesis of chiralγ-butyrolactones. This convergent and enantioselective approach to chiralγ-butyrolactones is practical and easily handled with protecting group free.

这一概念包括反应产率、对映选择性、配体用量以及反应时间四个重要反应参数，不仅适用同一反应不同催化体系的横向综合性评价，而且适用于某一特定反应催化体系的优化过程，有助于研究人员选择最佳的反应条件。4、我们发展了以手性γ-羟基-α，β-炔酸酯为关键中间体完成了手性γ-丁内酯类天然产物的对映立体选择性全合成，该关键中间体能够以我们的催化体系方便的对映选择性合成，之后的官能团转换方法成熟，易于操作，无需进行繁琐的官能团保护和脱保护过程，绿色经济。

Where ee〓 is the enantiomeric excess of the initial antipodal mixture, ee'is the enantiomeric excess of the recycled product fraction.

其中ee〓、ee'分别为初始对映体混合物和产物的对映体过量值。

Using one chiral ligand of each type respectively to investigate the infection of the structure and the amount of chiral ligands, the structure of reactant, the temprature and duration, solvent and reductive metal in pinacol coupling reactions.

三、系统考察了手性配体的结构和用量、底物结构、反应温度、时间、溶剂及还原金属对Pinacol偶联反应的化学产率、非对映选择性和对映选择性的影响。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐