差向异构体

The amidation of fatty acid with amine constructed the skeleton of malyngamide M,and then transformation of Z-olefin to E-olefin completed the synthesis of target molecule.

第4章详细阐述了使用高度会聚通用的路线完成含有末端烯氯结构的malyngamides O，P，Q，和R，以及Q和R的C-5差向异构体的全合成。

High performance liquid chromatography, carbon-13 nuclea magnetic resonance, chemical ionization mass spectrometry and gas chromatography with flame ionization detection have been employed for the identification and quantitative deter mlnation of the epimers of amygdalin.

高效液相色谱法、carbon-13 nuclea 磁场共振电离质谱、化学品与气相层析法，以氢火焰离子化检测被用来识别和定量的威慑 mlnation差向异构体的苦的。

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。

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。

To study the bioactive components from water soluble extract of the Chinese eaglewood, various column chromatography of Chinese eaglewood led to the isolation of ten compounds. Their structures were elucidated as 2,3-bis(3-hydroxyphenyl)- propan-1-ol (1), [(2R,3R)-3-(4-amino-3,5-dimethoxyphenyl)oxiran-2-yl]methanol (2), 8-chloro-4'- methoxy-5,6,7,3'-tetrahydroxy-2-(2-phenethyl)-5,6,7,8-tetrahydrochromone (3), 4'-methoxy-5,6,7,3'-tetrahydroxy-2--5,6,7,8-tetrahydrochromone (4), the isomer of 4 (5), 4'-methoxy-5,6,7,8-tetrahydroxy-2-(3'-hydroxyphenethyl)-5,6,7,8- tetrahydrochromenone (6), 4'-methoxyisoagarotetrol (7), 6-hydroxy-2-(2-hydroxy-2- phenethyl)-chromone (8), 6-hydroxy-2-(2-phenethyl)-chromone (9), 6-hydroxy-2-(4'- hydroxy-2-phenethyl)-chromone (10), and Guaiacylacetone (11) by means of spectral analysis and comparison with references.

为了进一步发现沉香中具有生理活性的化学成分，本文对国产沉香的水溶性成分进行了研究，从中分离得到11个化合物，通过红外、紫外、质谱、核磁共振(1H-NMR， 13C-NMR， COSY， HSQC， HMBC， ROESY)波谱解析，分别鉴定为：2，3-二(3-羟基苯基)-丙-1-醇(1)，[(2R，3R)-3-(4-氨基-3，5-二甲氧苯基)-2-氧化烯基]甲醇(2)，8-氯-4'-甲氧基-5，6，7，3'-四羟基-2-(2-苯乙基)-5，6，7，8-四氢色原酮(3)，4'-甲氧基-5，6，7，3'-四羟基-2-(2-苯乙基)-5，6，7，8-四氢色原酮(4)，化合物3的差向异构体(5)，4'-甲氧基-5，6，7，8-四羟基-2-(3'-羟基-2-苯乙基)-5，6，7，8-四氢色原酮(6)，4'-甲氧基异沉香四醇(7)，6-羟基-2-(2-羟基-2-苯乙基)色原酮(8)，6-羟基-2-(2-苯乙基)色原酮(9)，6-羟基-2-(4'-羟基-2-苯乙基)色原酮(10)和Guaiacylacetone (11)。

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。

This method can be applied in qualitative and quantitative analysis for Sitafloxacin epimers.

该方法可用于西他沙星差向异构体的定量分析。

Objective To develop an RP-HPLC for simultaneous determination of the epimers of glycyrrhizic acid in Radix Glycyrrhizae.

目的 建立RP-HPLC法同时测定甘草药材中甘草酸差向异构体的含量。

Under building a optimal HPLC condition,the epimers can be seperated well and can be studied by MS,LC-MS and NMR.

双氢青蒿素在有机溶媒中存在α与β差向异构体的转化过程。

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。

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。