丹参素及其衍生物合成方法的研究进展

中药丹参的活性成分丹参素是一种化学结构简单但特殊,并具有广泛的生理药理学活性的有机小分子化合物,丹参素类药物在抗心肌缺血和保肝护肝等方面疗效显著.然而,仅依靠从丹参中分离得到丹参素（或其衍生物）远不能满足临床需要.依靠化学方法简洁、高效的合成丹参素（或其衍生物）是该类药物研发亟须解决的问题之一.综述了近年来国内外相关报道,对外消旋体和光学纯丹参素的合成路线进行讨论,并就其构效关系进行初步分析;其中,光学纯丹参素的简单、高效、高选择性合成仍然是药物化学和有机化学关注的重点.新的合成方法和有关丹参素详细的构效关系研究,对开发丹参素类药物具有重要意义.     

酚羟基取代β-醛酮及其含糖类席夫碱衍生物的合成

鱼腥草素具广谱的抗菌活性,其药效团为β-醛酮结构.以含有羟基的苯乙酮为起始原料,合成了8个羟基取代及含有糖苷的芳香β-醛酮席夫碱衍生物,所合成化合物经过红外、核磁进行了结构表征.对所合成的化合物进行了抑菌活性测试,初步构效关系表明,苯环上酚羟基取代对抗菌活性有重要影响,烷氧基胺席夫碱种类对抑菌活性影响很大,酮羰基的存在对提高抗菌活性有利.     

红景天苷几种不同构型对其抗氧化活性的影响

红景天苷是一种主要从高原药用植物红景天和中药女贞子中分离得到的活性化合物. 本文在HF/6-31g(d,p)和B3LYP/6-31g(d,p)水平上对红景天苷及其六种衍生物进行了结构优化与性质计算,探讨了红景天苷的几何构型、电荷分布、化学键的Mulliken布居数及影响其抗氧化活性的几种结构因素,结果表明：酚羟基是红景天苷的活性部位;酚羟基的位置变化会影响到红景天苷的抗氧化活性;苯环与糖苷之间的碳链长短则对标题化合物的抗氧化活性基本无影响.     

α-酰氧基膦酸酯的合成研究

以乙醛酸和亚磷酸二乙酯为原料,合成α-羟基膦酸酯化合物,进一步羟基保护,羧基保护,合成了丹参素衍生物的中间体2-酰氧基-2-(二乙氧基膦酰基)乙酸甲酯,并用IR,1H谱,13C谱对化合物进行了表征.     

一种HCV抑制剂中间体9-羟基-6-氧-4-甲基菲啶的全合成

石蒜碱具有明显的抗丙肝病毒感染HCV(hepatitis C virus,HCV)活性,在对石蒜碱衍生物进行抗HCV活性研究时发现其中菲啶类化合物普遍具有比较良好的抗HCV活性,由于此类化合物活性优良,毒性较低,因此有必要对其进行深入的结构修饰与构效关系研究.对菲啶类衍生物重要合成中间体9-羟基-6-氧-4-甲基菲啶进行了全合成,该方法以2-溴-5-甲氧基苯甲酸为原料,包括酰胺化、偶联反应、以及脱甲基等3步,其中钯催化芳基-芳基,N-芳基一步偶联为该合成方法关键步骤,该方法步骤简便,原料简单易得,收率较高(总收率54%)可以为后续研究提供稳定的化合物来源.     

松油烯-4-醇衍生物构效关系

采用定性和定量方法分析了松油-4-醇及其14种衍生物对家蝇熏蒸和毒杀活性的构效关系.以Hyperchem软件的PM3模块对供试化合物进行量子化学计算,分别获得构效参数、轨道能级参数和单点净电荷参数.分析化合物各参数与其生物活性间的关系,并以偏最小二乘法(PLS)建立了一条电荷值—熏蒸活性模型(y=-0.159 989...     

齐墩果酸C-28位修饰物的合成与表征及其抑菌活性研究

齐墩果酸属于五环三萜类化合物,在自然界广泛分布,并且显示出多种生物活性,如：抗菌、抗炎、抗病毒及抗肿瘤等。但对其衍生物抑菌活性研究方面的报道较少。为了更为深入地研究齐墩果酸及其衍生物的构效关系,我们以具有较好生物活性的齐墩果酸为先导化合物,通过对其C-28位进行结构修饰,设计合成了6种未见报道的齐墩果酸衍生物。目标化合物的结构经IR和1HNMR表征确证,并对金黄色葡萄球菌、抗甲氧西林金黄色葡萄球菌、抗喹诺酮金黄色葡萄球菌、变形链球菌和大肠杆菌进行抑菌活性测试。结果表明,经修饰后的齐墩果酸衍生物对变形链球菌的抗菌活性较母体化合物有不同程度的提升。     

黄芩素和黄芩苷抗氧化活性与结构关系的密度泛函理论研究

采用密度泛函理论方法对黄芩素和黄芩苷分子进行构象扫描,获得2个化合物的最低能量构象并对其进行了全优化.从分子的几何结构、酚羟基解离能BDE、绝热电离势IP、HOMO和LUMO能级以及其能级差ΔE(LUMO-HOMO)等方面分析了2个化合物的抗氧化活性与结构的关系.结果表明,C6位的酚羟基为黄芩素和黄芩苷的最大反应活性位点.在非极性溶剂中,化合物抗氧化活性取决于分子中酚羟基的脱氢能力,黄芩苷的抗氧化活性大于黄芩素的抗氧化活性.在极性溶剂中,抗氧化活性取决于分子中单电子的电离势,黄芩苷的抗氧化活性大于黄芩素的抗氧化活性.     

羟基喜树碱10,20位双取代衍生物的合成及活性评价

根据喜树碱类药物的构效关系和前药设计理念,设计和合成了一系列新的10,20位双氨基甲酸酯取代的羟基喜树碱衍生物,且均为新化合物.体外细胞活性测试结果表明:这些化合物的细胞毒作用比喜树碱明显降低,可作为前药先导物进行更深入研究.     

7-羟基黄酮和7,8-二羟基黄酮的改良合成与结构修饰

利用改良的Baker-Venkatarama重排法,以乙酰芳基酚为原料,经过二步反应合成了7-羟基黄酮(3a)和7,8-二羟基黄酮(3b)．通过对7-羟基黄酮和7,8-二羟基黄酮A环酚羟基的结构修饰,分别合成了三个7位取代和二个含苯并二氧杂环的新黄酮衍生物(4-6,7a,7b)．所合成化合物的结构已由MS,^1HNMR,IR等波谱方法所证实、     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.