英语人>网络例句>对映体 相关的搜索结果
网络例句

对映体

与 对映体 相关的网络例句 [注:此内容来源于网络,仅供参考]

To our surprise we achieved the ligand 9, 11 and 29 with coordinating atoms fixing at benzylic and benzene ring positions, whose structure is unique in the planar chiral cyclophane chemistry.

以钯催化的烯丙基取代反应对配体进行了考察,硫醚或硒醚取代基在苄位取代的配体表现出更高的反应活性和更高的对映选择性,配体9和11均给出最高为94%的ee值。

Keywords hypophosphorous acid;thiol isomer thione isomers;enantiomer;proton transfer;isomerization reaction

单硫代次膦酸;硫酮式异构体;硫醇式异构体;对映异构体;质子转移异构化

The yields and ees obtained in the AD reaction of eight olefins utilizing 10 in PEG/NMO system were 72~90% and 79~96%(except for trans-5-decene and ally naphthyl ether).

3配体10和配体8是一对假对映异构体,在AD反应中立体选择面相反,可得到相反构型的产物。

Expanding pinacol reductive coupling reaction into asymmetric one with both diastereoselectivity and enantioselectivity may lead to its application in synthesising medicaments and biologic active compounds with structure of vicinal diol. Asymmetric pinacol coupling reaction is also the most compact and effecient method in synthesizing chiral ligands or chiral auxiliary with C〓 symmetry.

将这一反应发展成为既有高度的非对映选择性,又有高度对映选择性的不对称偶联反应在合成许多含有手性邻二醇结构的药物或生物活性物质将有更重要的应用,同时不对称Piancol偶联反应也是合成C〓对称性的邻二醇多用途手性配体或手性助剂的最为简捷有效的方法。

Respectively, glutamic acid derivatized β-CD has been synthesized with epoxy chloropropane as the intermediate, a water-insoluble yellow liquid was got after the acetylating of the by using acetic anhydride, which was used as a novel gas chromatographic CSP; A water-soluble β-CD polymer cross-linked with epoxy chloropropane has been synthesized, and the derivatives of β-CD polymer were synthesized by its alkylating and acetylating. The different β-CD derivatives were coated on silica capillary columns by dynamic method, the chromatographic properties and retention behaviors of the fused silica capillary columns were studied, the results showed that the β-CD derivatives had good stereoselectivity and separation results to some compounds, especially to various positional isomers and enantiomers.

本文还分别以环氧氯丙烷为中间体,合成了七{2,6-二-O-[3-(1,3-二羟基丙氨酸)]}-β-环糊精,再用醋酸酐将其乙酰化,得到了一种淡黄色粘稠液体,合成了一种新型的环糊精衍生物;以环氧氯丙烷作交联剂合成了一种水溶性的β-环糊精聚合物,再将其烷基化和酰基化,合成了β-环糊精聚合物的不同衍生物,用动态法将不同类型的β-环糊精衍生物涂渍在石英毛细管柱上,通过对所制备柱柱性能的测试和对一系列化合物的分离和保留行为的研究,结果表明所合成的β-环糊精衍生物对各类化合物,特别是对位置异构体和对映异构体具有较好的分离效果,显示了很强的立体选择性。

We selected different eluents according to different diasteroisomers and gained the singles of the diasteroisomers by the column chromatography.

经过简单易行的薄层色谱分析法选择了不同的洗脱剂,然后通过柱色谱分离,得到了多对非对映异构体的α-体和β-体。

This Sm-catalyzed reaction firstly efficiently realized the catalytic cycle in the tandem rearrangement/reduction reaction of α-hydroxy epoxides, and moreover the diastereoselective amplification could be distinctly observed when two C1 epimers in substrate were subjected to this catalytic tandem reaction.

该催化的多功能串联反应,高度非对映选择性地一步控制了含有季碳的三个相邻立体中心,有效地构建了&2-季碳1,3-二醇&结构单元,首次实现了此类重排—还原过程的催化循环,其中对于两个C1位的差向异构体底物,此反应具有明显的非对映选择性放大特点。

Though enantioslectivity in the epoxidation of some substrates with soluble polymer-supported tartrates is a little lower than that with solution-phase tartrates, it is higher than enantioslectivity with insoluble polystyrene resin-supported tartrates, linear poly s and corrosslinked poly s. It is obvious that soluble polymer-supported tartrates have good catalytic activity and enantioselectivity.

尽管可溶性聚合物支载的酒石酸酯在某些底物环氧化中的对映选择性比小分子酒石酸酯低一些,但明显优于文献报道的不溶性聚苯乙烯树脂支载的酒石酸酯、线形聚酒石酸酯和交联聚酒石酸酯配体,显示了良好的催化活性和对映选择性。

After the completion of reaction, ether is added to the resulting mixture to precipitate the tartrate and filter to recover the ligand. The recovered ligands keep good enantioselectivity only in first recycle, but compared with solution-phase of tartrate counterpart, using of soluble polymer-supported tartrates largely simplifies the workup of sharpless epoxidation.

反应完成后,向反应体系中加入乙醚使配体沉淀,过滤即可回收配体,虽然回收的配体只在第一次循环中保持了较好的对映选择性,但与使用小分子酒石酸酯配体相比,使用可溶性聚合物支载的酒石酸酯极大地简化了Sharpless环氧化反应的后处理。

Furthermore, the effects of ligands, metal and reaction time on the reaction were also researched, and the process of new ligand-metal catalysis for Diels-Alder reaction was also analyzed according to Evans" square planar mode and Corey"s tetrahedral manner.

我们对影响配体对映选择性能的各种因素,如配体结构、金属离子、反应时间等进行了研究,而且根据Evans的平面四方形模式与Corey的四面体过渡态理论为新配体—金属配合物催化的该反应提出了可能的反应机理,并对产物的优势构型作了理论分析。

第13/17页 首页 < ... 9 10 11 12 13 14 15 16 17 > 尾页
推荐网络例句

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务,乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐,因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。

Closes the eye, the deep breathing, all no longer are the dreams as if......

关闭眼睛,深呼吸,一切不再是梦想,犹如。。。。。。