异位差的

The efficient first asymmetric syntheses of-6β-hydroxy-7αH-eudesm-4-en-3-one, and its C-6 epimer were achieved starting from-dihydrocarvone, whichprovide a novel and efficient synthetic method to 6-oxgenated eudesmanes.

以-二氢香芹酮为原料，经五步反应，首次完成了6β-羟基-4(5)-烯-3-羰基桉烷及其6位差向异构体的立体选择合成，并为C-6位含氧官能团取代桉烷类化合物的合成提供了一种简便有效的方法。

The results indicate that thermal stabilities and decomposition mechanisms of the title compounds derived from the BDE, Ea and static electronic parameters are basically consistent. Homolysis of the N—NO2 bond is the initial step in the thermolysis of the title compounds, the meta-isomers are more stable than the para-isomers, and the ortho-isomers are the most sensitive.

结果表明，由BDE、Ea和静态电子结构参数推断的标题物热稳定性和热解机理的结论基本是一致的，N-NO2键均裂是标题物的热解引发步骤，间位取代异构体较对位取代异构体稳定，而邻位取代的异构体稳定性最差。

In chapter 6, seven pairs of diastereoisomers of podophyllum lignans at C4-position, including three pairs of spin labeled compounds, were separated by MEKC with 20mM sodium tetraborate-30mM SDS-10％ 2-propanol (pH=9.5-9.7) within 20min.

第六章：首次利用胶束电动毛细管色谱分离了七对抗癌药物鬼臼类木脂素在C4位的差向异构体，该方法可用来鉴定分析物的纯度、确定自旋标记化合物C4-H的构型等，为研究差向异构体不同的抗癌机制提供检测手段。

The analytical results have shown that p ro ducts mainly consisted of some monosubstituted, disubstituted and a few trisub stituted naphthalenes. Except the low activity of HZSM-5 catalyst, all other z eolite catalysts have higher activity. HY and Hβ catalytic activities were the highest, and their naphthalene conversions attained to 79.12 and 55.79 percent respectively, but their selectivities for 2-isopropylnaphthalene, 2,6-diisopropylnaphthalene(2,6-DIPN) and 2,7-diisopropylnaphthalene ( 2,7-DIPN) were too low. ZM catalysts had good activity and much better selecti vity, especially for ZM4-3, of which its 2,6-DIPN/2,7-DIPN ratio was 2.97. Th er efore, some zeolite catalysts are recommended for shape selective isopropylat ion of coal tar naphthalene.

研究结果表明，煤焦油萘异丙基化产物主要由一取代萘、二取代萘以及少量三取代萘组成；除HZSM-5活性较低以外，其它催化剂均有较高的反应活性，其中HY和Hβ反应活性最高，萘转化率分别达75.15％和55.96％，但β位产物的选择性较差；ZM类催化剂既有一定的活性，又有较高的β选择性，是萘择形异丙基化反应理想的备选催化剂。

In the paper, the multidentate carboxylic acid ligands were used to combine with Cd, resulting in the three dimensional MOCPs single crystals—C12H16CdN2O8, with a low temperature hydrothermal synthesis method. The sample was characterized with IR spectra to affirm the organic groups in the frameworks, single-crystal X-ray diffraction to determine the crystal structure and composition of the frameworks, N2 adsorption isotherms at low temperature to measure the specific surface area and pore size distribution, and with TGA/DGA analysis to scale the thermal stability. Furthermore, the dissolution property and the photocatalytic activity of MOCPs under the ultraviolet ray condition were explored.

本文用低温水热合成法，用多齿羧酸配体异烟酸和Cd配位合成出[Cd(C6H4O2N)2(H2O)4]∞三维晶体并进行了表征：采用红外光谱法确认骨架中的有机官能团；用单晶X射线衍射分析法测定MOCPs的晶体结构，并确定其骨架的组成；通过低温氮气吸附等温线测定了其比表面积和孔径分布；以热重分析和差热分析测定材料骨架的热稳定性；测定了晶体的溶解性能；最后以亚甲基蓝为目标降解物，对[Cd(C6H4O2N)2(H2O)4]∞的光催化活性及亚甲基蓝的氧化动力学进行了探索(来源：A2444BC论文网www.abclunwen.com)。

Nevertheless, the yield of pinacol was also strongly affected by the steric environment surrounding the carbonyl group. The pinacol coupling of aromatic aldehydes has been achieved with high yields under such a condition. However, the diastereose-lectivities of pinacols were not satisfying. Unfortunately, the ketones and most aliphatic aldehydes appeared inert under the same reaction conditions.

然而， 呐偶合反应的产率受到羰基周围环境的立体位阻影响较大，在此条件下，锌粉能有效地促进芳香族醛类化合物进行水相呐偶合反应，得到的呐醇产率高，但非对映异构体选择性差，而脂肪族醛类化合物得到的呐醇产率较低，在同样的条件下，酮类化合物不能顺利进行呐偶合反应。

The results showed that the addition leading to -2-phenyl-2-(2-vinylpiperidin-1-yl) ethanol 7 could proceed with good diastereoselectivity and excellent yield (95%).(3) The selective N-deprotection of -2-phenyl-2-(2-vinylpiperidin-1-yl) ethanol 2 without affecting the vinyl group in the substrate were untaken.(4) The Zip reaction for the transformation of -1-(3-aminopropyl)-3-methylazecan-2-one 8 to -7-Methyl-1, Sdiaza-cyclotetradecan-6-one 9 were undertaken. The results showed that, under controlled conditions, acceptable yields (43%) could be achieved and racemization can be minimized during the ring expansion reaction.

该合成路线与文献方法相比，反应条件较温和，也缩短了反应时间；(2)哌啶衍生物2与乙烯基格氏试剂进行加成反应的条件和立体选择性，取得了较好的结果（差向异构体比为80：20，产率95％左右）；(3)不饱和哌啶衍生物7在不影响碳碳双键的情况下去除苯基甘氨醇手性辅助基的条件；(4)具有羰基α位手性的氨基酰胺8在不同条件下经Zip重排反应转变为9的反应，控制反应条件，可使反应中消旋化减小到最小的程度。

These include catechin and gallocatechin (hydroxyls at positions 5' as well as at 3' and 4' as in catechin), their esters with gallic acid, catechin gallate, and gallocatechin gallate, and their epimers.

它们有几茶素和儿茶素(在5'位上以及如同儿茶素中一样在3'和4'位上羟基化)，它们与酸生成的酯，即儿茶素酸酯和儿茶素酸酯，以及它们的差向异构体。

Two approaches for the asymmetric syntheses of naturally occuring eudesmane-type triol kudtriol and 5-epi-kudtriol as well as their C-11 epimers were achieved starting from-dihydrocarvone through six and seven steps, respectively.

以-二氢香芹酮为原料，用两条合成路线分别经六、七步反应完成了三羟基桉烷类天然产物Kudtriol、5-epi-Kudtriol及它们的C-11位差向异构体的不对称全合成。

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。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。