薄层色谱法分离紫杉醇和三尖杉宁碱

建立了用薄层色谱分离紫杉醇和三尖杉宁碱的方法.方法中以正己烷-二氯甲烷-甲醇-三乙胺(体积比4.5∶3.5∶0.5∶1.0)四元体系为展开剂,在硅胶薄层板上成功地分离了紫杉醇和三尖杉宁碱,所得斑点清晰、无拖尾.同时以该体系为展开剂,使用薄层色谱法指导分离提取紫杉醇和三尖杉宁碱过程中反相色谱流分的合并,方法快速、简单、成本低,取得了满意的结果.     

微管蛋白的聚合和变性及紫杉醇的影响

微管系统在细胞中执行许多重要功能山．微管在细胞中呈现高度的时间和空间有序性,并与构成它的结构单元—一微管蛋白（土。l｝）lllil。）保持动态平衡,而且这种平衡是局域的和暂时的,Mit（Jlisou和Krscllner根据他们的微管体外实验及体内微管聚合特性称之为微管生长的动态不稳定性＊1．微管的生理功能正是与它的这种根本特性有关．另有研究发现微管是许多药物包括许多抗癌药物作用的靶子问．如紫杉醇（TaX01）＊等．因此国际上研究微管蛋白的聚合过程以及药物分子的作用是微管研究中的热点问题之一．生理状态下微管蛋白以。月异二聚体…     

Models for Taxol Biosynthesis: SeO2 Oxidation of Taxadiene

Together with the expected mono‐oxidized taxa‐4(20),11(12)‐diene‐5‐ol (1) and taxa‐4(5),11,20‐diene‐20‐ol (2), a new taxane skeleton, 3,12‐cyclotaxane (3), was obtained from chemical oxidation of taxadiene by selenium dioxide/t‐butylhydroperoxide.     

Solid-state NMR studies of the molecular structure of Taxol

Solid-state 13C{1H} cross-polarization/magic angle spinning spectroscopy (CP/MAS) has been utilized to extract the molecular structure information of Taxol, which is an anti-tumor therapeutic medicine extracted from the yew bark. The 13C signals have chemical shift values quite consistent with those measured in solution phase, and the overall chemical shift range is over 200 ppm. Notably, most of the 13C resonances of the taxane ring have two clearly resolved spectral components except the resonance peaks of C-15, C-16 and C-17, which are located at the central part of the taxane ring. On the basis of our NMR data, we propose that these doublets originate from two slightly different molecular conformations of the taxane ring and still the central part of the ring remains structurally similar. Furthermore, it is demonstrated that the 13C chemical shift difference deduced from the doublet splittings can serve as a direct measure of the structural difference between the two conformations, which could possibly correlate with the anti-tumor activity of Taxol.     

反相HPLC法分析红豆杉树皮和树叶中紫杉醇及其类似物含量的研究

建立了红豆杉树皮和树叶中紫杉醇及四种类似物１０－脱乙酰浆果赤霉素Ⅲ（１０－ｄｅａｃｅｔｌｙ－ｂａｃｃａｔｉｎⅢ）浆果赤霉素（Ｂａｃｃａｔｉｎ（Ⅲ），脱乙酰－７－表－紫杉醇（１０ｄｅａｃｅｔｙｌ－７－ｅｐｉ－ｔａｘｏｌ）和Ｃｅｐｈａｌｏａｎｎｉｎｅ）的梯度和等梯度高效液相色谱分析方法。     

正相色谱和反相色谱法分离提纯东北红豆杉中紫杉醇和三尖杉宁碱

以东北红豆杉树叶为原料,采用正相色谱和反相色谱法分离提纯了紫杉醇和三尖杉宁碱。反相色谱中使用了一种新颖的高分子填料。东北红豆杉枝叶经过一次正相色谱分离后,再经两次反相色谱分离,分离得到两种白色针状固体。经1H NMR和13C NMR测试表明,两种物质分别为紫杉醇和三尖杉宁碱,纯度达到98%以上,产率分别为树叶干重的0.0022%和0.0018%,回收率大于70%。     

Synthesis of a bicyclo[5.3.1]undecene by a facile domino enyne cross-metathesis/IMDA

An efficient domino cross-enyne metathesis/intramolecular Diels-Alder reaction is demonstrated for the construction of a bicyclo[5.3.1]undecene.     

Determination of taxol in Taxus species grown in Hungary by high-performance liquid chromatography-diode array detection effect of vegetative period

The influence of a vegetative period on the taxol content in the needles of Taxus brevifolia grown in Hungary was determined using porous graphitized carbon column and a HPLC-diode array detection system. The relative standard deviation of the retention time of taxol peak was 1.24%, the peak symmetry 1.06–1.07 indicating the reliability of the HPLC systems. It was found that the accuracy of the peak purity test can be enhanced by carrying out the test at various wavelengths. It was established that the taxol content is considerably higher in the winter months and taqxol is purer in the same period. Taxol content also depends on the production site and taxol exctracted from the foliage contains more taxoteres than taxol extracted from bark.