查询词典 chiral

Chiral auxiliary controlled asymmetric reaction is one of the main methods in asymmetric synthesis.

手性助剂控制的不对称反应是不对称合成的主要方法之一。

The determination of the absolute configuration of chiral molecules is an important issue in organic chemistry.

手性分子绝对构型的确定是一个极其重要且长期存在的问题。

A novel planar chiral diferrocenylimine-diols 6 was synthesized by the condensation of R, S(subscript p-1-(2-diphenyl hydroxyl methyl) ferrocenylethylamine [R, S(subscript p-4] with phthaldehyde in anhydrous ethanol, and was crystallographically characterized.

通过R，S(下标 p-1-（2-二苯基羟甲基）二茂铁乙胺[R，S(下标 p-4]和对苯二甲醛在无水乙醇中的缩合反应合成了一种新型平面手性双二茂铁亚胺二醇化合物6，并经X-射线衍射分析它的晶体结构。

The masses of N and Δ baryons are calculated based on the confining potential amended or not in chiral SU (3) quark model and three-body theory method. The results shown that amendment can improve some values, but the improvement is still not satisfactory and the quark model can described octet and decuplet well but excited baryons.

利用手征SU(3)夸克模型和三体理论方法，在考虑禁闭势带修正项和不带修正项两种情况下，计算了N和Δ重子质量。N和Δ重子谱的计算结果表明，增加修正项能改善一些计算值，但改善程度仍然不是很令人满意；SU(3)夸克模型能够很好描述重子的八重态和十重态，但不能很好地描述激发态的重子。

For certain reactions, they function as chemoenzymes and produce both good chemical and optical yields. Over the last decade a wide range of C〓-symmetric chiral bisoxazoline ligands have been synthesized from readily available diacid derivatives and amino alcohols.

但是，手性双噁唑啉催化的某些不对称反应的机理以及影响双噁唑啉分子催化性能的结构要素目前仍不是很清楚，诱导某些反应的不对称选择性仍有待于进一步提高，因此需设计和合成新的双噁唑啉类配体。

The third part of this thesis is reactive simulating calculation In this section, some well-known auxiliaries are selected to compute in density functional theory B3LYP on Gaussian 03, from which the relationship between reaction active energies of transition states and enantiomeric excess of chiral products homoallylic alcohols isobtained based on relative reactive ratio theory. Using this relationship, calculations on the reaction of more than eight auxiliaries with four other aldehydes are carried out in AMI and MNDO, proving that N,N\'-dibenzyl tartamide has higher enantioselectivity than others in this reaction.

第三部分为计算化学部分，运用密度泛函理论B3LYP方法在Gaussian03软件上对已经报道的几种手性配体参与的醛不对称烯丙基化反应过程进行模拟计算，基于相对反应速率理论找出两种构型过渡态间活化能的差异与产物光学收率之间的关系；并以此为基础，用AM1和MNDO方法对上述合成的几种配体控制的反应过程进行量化计算，从而在理论上证实了N-苄基酒石酸二酰胺配体在醛的不对称烯丙基化反应中具有较高的立体选择性。

Omeprazole racemate was resolved respectively by simulated moving bed chromatography and batch chromatography with the coated cellulose triphenylcarbamate as chiral stationary phase and ethanol containing 0.1% diethylamine as mobile phase.

用纤维素三苯基氨基甲酸酯涂敷型手性固定相和含0.1%二乙胺的乙醇溶液，研究了模拟移动床色谱和间歇色谱对奥美拉唑对映体的拆分。

Optically active β,δ-dihydroxy esters have been widely used in the synthesis of natural products, polyol fragments, and chiral drugs.

具有光学活性的β，δ-二羟基酯已经在天然产品、多羟基化合物以及手性药物的合成中得到了广泛的运用。

The first asymmetric total synthesis of coumarinolignoids Daphneticin and it's enantiomer was accomplished starting from 7-hydroxycoumarin and 3, 4, 5-trimethoxybenzaldehyde, in which Sharpless asymmetric dihydroxy reaction was used to construct chiral center, and Mitsunobu reaction was used to obtain desired configuration.

并以7-羟基香豆素和3，4，5-三甲氧基苯甲醛为起始原料，用Sharpless不对称双羟化反应构筑手性中心，用Mitsunobu偶联反应作为关键步骤，合成了手性的香豆素木脂素Daphneticin及其异构体。

Studing on samarium diiodide promoted asymmetric intramolecular reducing coupling reactions, we have made the resolution of the racemic biaryl dials by using enantiomeric N-tert-butanesulfinamine as the resolving reagent successfully and thus obtained a series of axially chiral biaryl dials with high enantiomeric excess.

中文摘要在二碘化钐促进的分子内不对称还原偶联反应中，我们不仅对联芳基二醛底物的合成路线进行了优化，还发现N-叔丁基亚磺酰胺辅基可以作为手性试剂，成功地对联芳基骨架二醛化合物进行拆分，得到高对映体过量的轴手性二醛类化合物。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。