查询词典 chiral

The chiral ligands la-lf were used in the copper catalyzed asymmetric addition of diethylzinc to imines.

第二部分探索了一个新的含氮杂环丙烷的手性膦配体2的合成方法。

At the concentration of 5×10〓. To get optical active target compounds,α-aminophosphonates were prepared by the stereoselective addition of phosphates to chiral imines in the presence of catalyst 〓.

不饱和烯酸杂环衍生物的合成与生物活性研究当今农药发展主要表现为开发高效、低毒、易降解、对环境友好的绿色农药。

In the fifth part, asymmetric synthesis of β,γ-trans-alkenyl α-amino esters was achieved by chiral phosphoric acid catalyzed transfer hydrogenation of β,γ-alkynyl α-imino esters. Utilizing Hantzsch ester as the hydrogen donor, both the alkyne and imine moieties of β,γ-alkynyl α-imino esters were reduced to yield β,γ-trans-alkenyl α-amino esters with up to 96% ee.

第五部分工作中，使用手性磷酸作为催化剂，Hantzsch酯作为氢源，β，γ-炔烃取代的α-酮酸酯亚胺中的炔键和亚胺官能团均被还原，以中等的收率和优秀的对映选择性（up to 96% ee）得到β，γ-反式烯烃取代的α-氨基酸衍生物。

Recently, the propagation characteristics of electromagnetic waves in chirowaveguides have been deeply investigated by Pennsylvania University, US Navy laboratory and so on.Some units inlands are also working at theory and experiment on chiral medium.

近年来，以美国的宾夕法尼亚大学、美国海军实验室和芬兰的赫尔辛基技术大学为代表的一些研究机构开展了对旋波媒质以及它和电磁波场之间相互作用及其应用方面的研究工作，国内某些单位也正在进行有关方面的理论研究和实验探索。

A new method for the separation and purification of chiral mandelic acid by heated benzene extraction and refrigeration crystal was established. The ionization constant of mandelic acid was mensurated by pH potentiometer titration.

采用pH值电位滴定法测定了扁桃酸的离解常数，采用高效液相色谱法考察了扁桃酸在不同溶剂中的溶解度曲线和在苯-水体系中于不同pH值条件时的分配率，建立了热苯萃取和冷却结晶的扁桃酸纯化工艺。

Chiral drugs ; mandelic acid ; ionization constant ; solubility ; mensuration

手性药物；扁桃酸；离解常数；溶解度；测定

Meanwhile, the chiral recognition mechanism of the isomers is introduced briefly.

同时， 简要介绍了作为手性固定相对不同异构体的识别机理。

Another example of chiral recognition is found in the effect these two carvone isomers have on rates of reaction.

我们也发现这两个香芹酮异构体对反应速率有不同影响的其他手性识别5的例子。

In the first part of this thesis, a formal [4+2] cycloaddition of ketenes with N-benzoyldiazenes catalyzed by chiral NHCs was studied, which gave 1,3,4-oxadiazin-6-ones in very high yields and enantioselectivites.

论文的第一部分内容是在手性氮杂环卡宾的催化下，烯酮与N-苯甲酰偶氮化合物的环加成反应，合成各种手性的噁二嗪酮，它们还可以经过简单的两步一锅法制备手性氨基酯。

Asymmetric reduction of prochiral ketone to these chiral alcohol s by active microbe cells is one of the most promising routes.

以4-氯苯乙酮为苯环上含卤素的芳香酮的模型底物，研究了活性酵母细胞在水相体系中催化该类芳香酮不对称还原合成相应手性醇的反应特性。

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％。