6-羟基石松碱与乙酰胆碱酯酶的相互作用

目前治疗阿尔茨海默症(Alzheimer’s disease,AD)的主要药物为乙酰胆碱酯酶抑制剂(AChEI).为探讨石松碱类化合物对AChE的抑制作用,以6-羟基石松碱(6-hydroxylycopodine,HLD)为对象,应用核磁共振、分子对接、酶活性测定、分子动力学模拟及自由能分析,研究了HLD与AChE的相互作用.研究发现6-羟基石松碱对乙酰胆碱酯酶具有混合型抑制作用,其结合作用主要来自氢键和范德华作用.     

石松生物碱集成合成的研究进展

鉴于同一家族天然产物在化学结构和生物合成途径上的相关性,2011年Mac Millan等提出利用相同或相似的关键中间体快速高效合成天然产物家族化合物的集成合成策略,近年来该策略被应用于多个家族天然产物的合成中.石松生物碱是一类结构奇特且复杂多样的生物碱,部分成员化合物表现出良好的生物活性.综述了国内外有机合成化学家对石松生物碱家族化合物的集成合成研究进展.     

低压催化氚化亮石松碱的定位效应的研究

近年来,中草药有效成分的研究引起国内外有关学者普遍关注。氚标记中草药有效成分是研究其相应的药代动力学和代谢产物的主要手段,它具有操作简便,条件温和等优点,但是一般氚化方法均不能明确给出氚化位置。而研究氚化定位效应又是药理工作者急待解决的重要课题,所以在很大程度上限制了该项技术的使用范围。最近,郑冬珠等人用FX—100型核磁共振谱仪给出了在PdO催化剂存在条件下,低压氚化亮石松碱的氚化位置及其相对含量。本文在前文基础上,以亮石松碱为底物,根据Fraser和Garnett等人提出的氢—氚同位素交换反应动力学理论,采用CNDO/2法,对PdO催化亮石松碱的立体构型讲行了计算,得出一些有意义的结果。     

石松生物碱(+)-Fawcettimine,(+)-Fawcettidine和(-)-8-Deoxyserratinine的全合成

Angew.Chem.Int.Ed.2012,51,491～495石松类生物碱(Lycopodium alkaloids)是从蕨类植物石松和其近缘植物中分得的结构类似,具有相同生源的一类结构奇特且骨架变化多样的生物碱.这类生物碱具有很多重要的生物学功能,最具代表性的如石杉碱甲对治疗老年痴呆症有显著疗效.由于该类生物碱具有新颖复杂的化学结构和重要的生物功能,对于该天然产物的全合成研究已经成为近十年内国际有机合成领域的难点和热点.天津大学药学院和北京生命科学研究所雷晓光教授课题组最近报道完成了该家族中三个天然产物(+)-Fawcettimine,     

小檗碱衍生物合成及生理活性研究进展

小檗碱是一种季铵型异喹啉生物碱,主要存在于毛茛科、芸香科和小檗科等植物中,具有多种药理功能.近年来,大量小檗碱衍生物的合成,极大提高了小檗碱的生理活性及拓展了小檗碱的应用范围.文章重点综述了小檗碱及其衍生物的生物及化学合成,简述了其生理活性,并对新型小檗碱衍生物合成的设计方向作了展望.     

天然产物退热碱和异退热碱的不对称合成进展

天然产物退热碱和异退热碱以及类似结构化合物表现出优异的抗疟疾活性,且未见产生耐药性的报道.本文综述了它们的各种不对称合成方法,评价了其优缺点,并简要介绍了其衍生物的合成.     

石杉碱甲的合成研究进展

石杉碱甲是中国独创的治疗老年痴呆症的药物.由于其显著的疗效,长期以来,一直受到人们的关注和研究.目前石杉碱甲在美国已经进入三期临床研究,而在中国也已获批上市并进入四期临床.由于石杉碱甲在千层塔中的含量仅为万分之一左右,且千层塔的生长周期较长,所以石杉碱甲的化学合成将成为获得该药物的一种有效途径.二十多年来,化学合成石杉碱甲从消旋化合成到手性合成,从毫克级放大到几百克级合成都体现了这一领域的长足发展.其合成工艺和路线也在安全性、实用性方面大为改善.系统综述了1989年到2013年间石杉碱甲化学合成的进展,以期为进一步完善石杉碱甲化学合成提供参考.     

斯替宁碱的合成方法研究进展

具有1H-吡咯并[1,2-a]氮杂和多取代全氢吲哚结构的斯替宁碱是百部生物碱的代表性结构,其多环结构和连续的七个手性中心对不对称合成化学极具挑战性.按斯替宁碱合成中使用的关键方法分类,对斯替宁碱的合成研究进展进行了综述.     

用天然沸石合成ZSM-5分子筛

以天然沸石作为硅铝源合成分子筛有着原料丰富、成本低廉等特点.近年来,用天然沸石作为原料合成分子筛的工作已有报道.但合成体系均为碱性介质,并有模板剂.Guth等在非碱体系合成了ZSN-5分子筛.李赫咺等采用直接法,以水玻璃和硫酸铝为原科,成功地合成了ZSM-5分子筛,但在非碱体系和直接法用天然沸石合成ZSM-5分子筛的工作尚未见报道.作者以天然沸石矿为原料,首次采用水热晶化法在非碱体系和直接法合成出ZSM-5分子筛,并对其结构和性能进行了考察.     

5-溴水杨醛亚胺合铜(Ⅱ)类配合物的合成与抑菌活性

希夫碱类药物由于其良好的抗肿瘤、抗细菌、抗病毒、抗真菌等多种生物活性而日益受到人们的重视[1,2].近年来我们合成了一系列水杨醛亚胺希夫碱药物[3,4],发现取代水杨醛亚胺希夫碱药物的杀菌抑霉活性更高,抗菌谱更广.故又设计合成了5-溴水杨醛缩苯胺、邻甲(间氯)苯胺新希夫碱及其Cu(Ⅱ)配合物,并由元素分析和红外光谱所表征.合成路线如下:     

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.     

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。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

化学计量中不确定度评定研究进展

测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

On the possibilities of theoretical analysis of kinetics of the thermal decomposition of solids

The main reasons for changes in the environment surrounding us are discussed on the basis of thermodynamics of irreversible processes. Subsequently, relations between thermodynamics of irreversible processes and chemical kinetics are shown, then the possibilities of theoretical determination of rate constants on the framework of the modified RRKM theory are presented. These latter considerations are supplemented by a discussion concerning the possibilities of determining the activation barriers and structural changes (necessary to account for entropy changes upon reaction) in molecules kept on the surface of crystalline phases by combination of quantum chemistry methods for isolated molecules with those reflecting the influence of the environment (i.e. interaction within the lattice). Finally, the future of theoretical methods in examining the reactivity of solid state systems is briefly discussed.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

NiY分子筛表面酸性影响其选择性吸附脱硫性能的机理研究

采用原位红外光谱技术,以噻吩、环己烯和苯为模型探针分子,分别考察单一烃分子在NiY分子筛上的吸附与反应行为以及噻吩与烯烃、芳烃间的竞争吸附和催化反应行为。单一探针分子吸附研究发现,NiY分子筛中与Ni物种相关的Lewis(L)酸位是噻吩的选择性吸附活性位;噻吩和环己烯在NiY分子筛中Brnsted(B)酸位上发生的质子化和低聚反应明显弱于HY分子筛。双探针分子竞争吸附研究发现,环己烯二聚体在NiY中强B酸位上的强化学吸附与噻吩存在显著的竞争吸附行为。另外,苯和噻吩在NiY上的竞争吸附现象在373K时明显减弱。由此,在选择性吸附脱硫过程中,减少吸附剂表面B酸中心可降低烯烃对噻吩的竞争吸附,另外适当提高吸附体系的温度可以有效避免芳烃对噻吩的竞争吸附。     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.