鬼臼脂素及其木质素的高效液相色谱分析

桃儿七(Podophyllum emodi Wall.Var Chininsis Sprague)根茎中分离得到的鬼臼脂素是一种具有很大毒性的抗癌天然产物,是抗癌新药VP16-213和VM26等的半合成原料。 早期文献报道,鬼臼脂素定量分析用薄层色谱—洗脱分光光度法,该法步骤多、费时、斑点定位困难,因而误差较大;     

4β-氨基-4脱氧鬼臼毒素和4β-氨基-4脱氧-4''''-去甲基鬼臼毒素的两种新合成方法

我们在研究抗肿瘤活性物质的基础上[1～ 5 ],注意到鬼臼类化合物具有抗癌活性 ,但其毒副作用较大 ,我们对其结构进行了改造 ,以研制活性更高而毒性更小的新的衍生物 .从以前有关鬼臼毒素及其类似物的构效关系研究中已得出以下几个方面的结构要求是保持其抗癌活性必须具备的条件 :(ａ)在4’ 位有一个酚羟基 ;(ｂ)Ｃ 4取代基位是 β构型 ;(ｃ)具有反式内酯环[6 ].研究表明 ,4 β 酰胺基的鬼臼衍生物具有较强的抗癌活性[7].而 4 β 氨基 4脱氧鬼臼毒素和 4 β 氨基 4脱氧 4’去甲基鬼臼毒素是合成此类衍生物的最重要中间体 .合成这两个化合物的…     

楝酰胺(Rocaglamide)类化合物研究进展

近20年来, 从楝属植物中不断有楝酰胺类化合物及其类似物被分离并确定结构. 生物活性测定结果表明, 楝酰胺类化合物大多具有良好的杀虫活性, 有些化合物则显示出抗癌功能. 对楝酰胺类化合物的研究进行了全面综述.     

亲水作用电色谱用于吡啶类化合物的分离

 采用亲水电色谱对强极性吡啶类化合物进行了分离。以亲水性的强阳离子交换填料作固定相,乙腈-磷酸-三乙胺缓冲液作流动相,考察了流动相中有机改性剂含量、离子强度及流动相pH对吡啶类化合物保留行为的影响。结果表明,在亲水电色谱模式下,流动相中有机改性剂含量对吡啶类化合物保留有较大影响,随着流动相中乙腈含量的增加,吡啶类化合物的保留迅速增强;较高pH值有利于吡啶类化合物的峰形改善。实验证明,亲水电色谱是一种适用于极性化合物分离的新型微分离方法。     

植物多糖清除羟自由基作用的研究

研究当归、黄芪、鬼臼和猫人参的多糖对羟自由基的清除作用.采用分光光度法测定羟自由基清除率,并计算出半数清除率(IC50).当归多糖、黄芪多糖、鬼臼多糖对羟自由基的IC50分别为1.38 mg/mL、0.485 mg/mL、0.1 mg/mL,猫人参的最大清除率仅为36.84%.其清除能力鬼臼多糖＞黄芪多糖＞当归多糖＞猫人参多糖.鬼臼多糖、黄芪多糖均具有较强的清除自由基作用,且清除能力与浓度呈明显的正相关.     

鬼臼类二芳醚农药的合成研究

鬼臼毒素(Podophyllotoxion)是从盾叶鬼臼(Podophyllum peltatum)和西藏鬼臼(P.emodi)等植物中提取分离的一种具有显著的抗肿瘤、抗病毒活性作用的活性成分,在我国资源丰富.西北农林科技大学无公害农药研究服务中心首次发现并报道了柏科圆柏属植物砂地柏的杀虫活性.从1999年以来,我们对该类植物进行了比较系统的研究,已证明鬼臼毒素(Podophyllotoxin)及脱氧鬼臼毒素(deoxypodophyllotoxin)为其重要的活性成分[1].基于在农药分子中引入二芳醚结构可以显著改善农药的理化性质和生物活性(如:提高光学稳定性、降低对哺乳动物的毒性,扩大生物活性谱等特点)[2],我们设计合成了含有鬼臼类二芳醚的十个新化合物,可望得到高效低毒的具有显著活性的农药[3],该类化合物结构经IR,1H NMR,13C NMR,ESI-MS,HRMS等所证实.其合成路线如下:     

α-硼取代羰基类化合物的合成进展

硼取代羰基类化合物传统被认为是热力学上不稳定的化合物,容易发生1,3-硼迁移.近年来,随着对sp3杂化的硼或是四配位硼基团的研究深入,合成稳定且可分离的α-硼取代羰基类化合物的方法被逐渐发展.这些方法包括利用重氮酸酯、硫叶立德等卡宾前体对硼烷的插入反应, α,β-不饱和羰基类化合物的自由基硼氢化反应,以及含硼化合物的后阶段结构修饰反应等.根据不同的反应类型,对近年来合成α-硼取代羰基类化合物的反应进行了综述,并对现有的挑战及未来的研究方向进行了讨论.     

鬼臼及其羧酸酯类化合物2位立体异构体的EI MS质谱研究

鬼臼(podophyllotoxin)及其衍生物在抗癌方面表现出良好的活性。最近,Lopez-perez等人研究了合成的鬼臼羧酸酯类化合物的细胞活性,发现鬼臼的4位降冰片烯酯化合物在对P-388,A-549,HT-29和MEL-28有较母体鬼臼强3~5倍的活性[1],因此引起了人们对鬼臼酯类化合物抗癌活性与结构特点     

鱼藤酮类衍生物的研究进展

鱼藤酮类衍生物是一类从鱼藤属等植物中提取出来的具有杀虫活性的异黄酮类化合物. 从1932年至今, 已经从植物中提取分离出47种鱼藤酮类化合物. 这一类化合物之所以具有很好的杀虫活性, 是由于对还原型烟酰胺腺嘌呤二核甘酸(NADH)的抑制作用而阻断了线粒体的呼吸. 对天然鱼藤酮类衍生物的结构、活性和合成方面的研究分别进行了概括.     

基质固相分散提取桃儿七根中鬼臼毒苷和异鬼臼苦酮

采用基质固相分散提取桃儿七根中的鬼臼毒苷和异鬼臼苦酮,并用高校液相色谱法进行了测定,选择硅胶为分散剂和甲醇为洗脱剂对鬼臼毒苷进行提取,硅藻土为分散剂和甲醇为洗脱剂对异鬼臼苦酮进行提取,与回流提取法相比,提取率较高。     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.