查询词典 pinacol

In addition, a new vicinal diol with potential practical value was prepared by asymmetric pinacol coupling reaction under the inducement of substrate.

另外，利用底物诱导的不对称Pinacol偶联反应合成了具有潜在实用价值的新的手性邻二醇。

Pinacol reductive coupling reaction of aldehyde and ketone is one of the most important methods in forming C-C bond, which may also produce vicinal diol as valuable intermediate compound applied in the synthesise of natrual products.

醛酮的Pinacol还原偶联反应是合成C—C键的重要方法之一，同时合成的邻二醇类化合物是重要的有机合成中间体，已被应用于许多含有邻二醇结构的复杂天然化合物总合成中。

The pinacol coupling of carbonyl compounds affording pinacol s is an important method for the formation of 1, 2-diols and one of the most powerful methods for constructing carbon-carbon bond.

醛酮的片呐醇偶联是合成片呐醇的经典而有效的方法之一，也是形成C-C键的有效途径，一般通过醛酮与金属试剂或金属络合物作用来实现。

Now, a convenient, efficient pinacol coupling of aldehydes mediated by zinc in good yields has been carried out in ammonia water in the presence of a little crown ether. Adding a small amount of crown ether was highly effective to enhance the yields of pinacol from 63% to 84%.

本文报道一种简便、有效的水相呐偶合反应，它是在含有少量冠醚的稀氨水溶液中，使用锌粉促进醛基化合物进行水相呐偶合反应，其中加入少量的冠醚有助于提高反应的产率，呐醇产率由63%提高到84%。

Structure of the dehydration product I of pinacol under acidic condition was determine The results show that the dehydration reaction of pinacol gains an advantage over rearrangement reaction.

结果表明，在酸性条件下颇哪醇的脱水反应优于重排反应，由此合成了1，2，4-三苯基环戊二烯。

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。

Discussing the mechanisms of the pinacol coupling reactions catalyzed by bidentate and tetradentate chiral ligands.

四、分别对二齿手性配体和四齿手性配体催化Pinacol偶联反应机理进行了探讨。

The 91% ee value was obtained by the pinacol coupling reaction catalyzed by 15mol% Schiff-base prepared by the chiral 1, 2-Diphenyethylenediamine and 2-pyridinecarboxaldehyde.

2由手性1，2-二苯基二胺与两分子2-吡啶醛缩合的Schiff-Base催化的Pinacol偶联反应，仅用15mmol％的量，可取得91％的ee值，这是不对称Pinacol偶联反应最好的结果之一。

The synthetic conditions of 4,4 dimethyl 3 oxopentanenitrile prepared sequentially from acetone through pinacol , pinacol one and α chloro pinacol one were investigated.

对以丙酮为原料、先依次制得片呐醇、片呐酮、α氯代片呐酮、最后由α氯代片呐酮与NaCN反应制得 4，4 二甲基 3 氧戊腈最后两步的反应条件进行了研究。

Methods for synthesizing of pinacol are reviewed,the difference of catalytic effects and stereoselectivity with various catalytic systems are introduced in this paper.Highlights are laid on the mechanism and stereoselectivity of new synthetic methods catalyzed by low valent Samarium, Titanium and Trimethyl chlorosilane, etc.

频哪醇合成新进展* The Recent Progress in the Synthesis of Pinacol 李有桂蒋昌盛尤田耙**(中国科学技术大学化学系合肥 230026)本文综述了合成频哪醇的方法，介绍了不同催化体系的催化效果和立体选择性的差异，着重介绍了低价钐、低价钛、三甲基氯硅烷等新的合成频哪醇反应的机理和立体选择性。

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％。