Topochemical models for anti-HIV activity of 1-alkoxy-5-alkyl-6-(arylthio)uracils

Relationship between topochemical indices and anti-HIV-1 (HTLV-III) inhibitory activity of 1-alkoxy-5-alkyl-6-(arylthio)uracils has been studied. Superadjacency, an adjacency-cum-distance-based, topochemical index and Wiener’s, a distance-based, topochemical index were calculated for a set of 36 1-alkoxy-5-alkyl-6-(arylthio)uracils. Resulting data were analyzed and suitable models were developed after identification of the active ranges. Subsequently, a biological activity was assigned to each of the compounds using these models and compared with the reported anti-HIV-1 activity. High accuracy of prediction was observed using these models. Statistical analysis revealed significance of the proposed models as well as a lack of correlation between the topochemical indices employed for the chosen data set.     

有机化合物结构的唯一性表征方法研究──一个高选择性的拓扑指数

以扩展连接矩阵EA的幂级数函数为基础,建立了一个新的拓扑指数EATI,该指数对1～22个碳原子的所有3807434个烷烃异构体的指认并不出现简并,且能区分含杂原子的化合物,其唯一性良好。该指数可用于数据库中替代CAS登录号进行结构的编码、管理及检索。     

Topochemical models for prediction of anti-tumor activity of 3-aminopyrazoles

Relationship between topochemical indices and inhibition of CDK2/cyclin A by 3-aminopyrazoles was investigated using a data set comprising of 42 3-aminopyrazoles. Three topochemical indices--the Wiener's topochemical index--a distance based topochemical index, atomic molecular connectivity index--an adjacency based topochemical index and superadjacency topochemical index--an adjacency-cum-distance based topochemical index were used for the present investigations. The values of Wiener's topochemical index, atomic molecular connectivity index and superadjacency topochemical index for each of the 42 compounds comprising the data set were computed using an in-house computer program. Resultant data was subsequently analyzed and suitable models were developed after identification of the active ranges. Subsequently, a biological activity was assigned to each of the compounds using these models, which was then compared with the reported CDK2/cyclin A inhibitory activity. High accuracy of prediction ranging from 86 to 89% was observed using these models.     

Structure-activity study of antiepilepticN-aryl-isoxazolecarboxamides/N-isoxazolylbenzamide analogs using Wiener's topological index

The relationship between Wiener's topological index and the antiepileptic activity of a series ofN-aryl-isoxazole carboxamides/N-isoxazolylbenzamide analogs has been investigated. Values of Wiener's topological index for 69 compounds constituting the training set were computed and an active range was identified. Each analog was subsequently assigned an activity which was then compared with the reported antiepileptic activity against the maximal electroshock seizure (MES) test. Due to significant correlation between antiepileptic activity and Wiener's topological index, it was possible to predict antiepileptic activity with an accuracy of 91 % in the active range.     

A graph-theoretical method for stepwise factorisation of symmetric graphs for simultaneous determination of eigenvectors and eigenvalues

A simple pictorial algorithm for factorisation of symmetric chemical graphs (weighted and unweighted) leading to simultaneous determination of their eigenvalues and eigenvectors has been devised. The method does not require group-theoretical techniques (viz. identification of the point group of the species under study, formation of symmetryadopted linear combinations using character tables etc.). It requires consideration of only one symmetry element, e.g., a reflection plane and is based on elementary row and column operations which keep the secular determinant of the adjacency matrix unchanged (except possibly for a multiplicative constant).     

The Spectropolarimetric Back-Titration of Rhodium(III) with the Chiral Ligand (R,R)-(-)-Trans-1, 2-Cyclohexanediaminetetraacetic Acid

Abstract

Spectropolarimetric back-titrations are described for rhodium(III); the optically active ligand (R, R)-(-)-t?ans-l, 2-cyclohexanediaminetetraacetic acid (R, R(-)CDTA) is used as the complexing agent and cadmium(II) ion as the back-titrant. The optical rotation is monitored throughout the titration, and the optically active ligand and stereospecifically formed complexes serve as self-indicators. The end points are determined graphically by straight-line extrapolations from a plot of volume-corrected observed rotations versus ml of titrant. The rhodium(III) titration plots are representative of normal spectro-polarimetric back-titrations. The range of analyses of rhodium(III) was from 40–0.5 mg.     

L(-)-α-苯乙胺拆分2-萘甲酸类立方烷光二聚体

使用L(-)-α-苯乙胺作为手性衍生化试剂,拆分了外消旋的类立方烷2-萘甲酸光二聚体,并通过圆二色谱进行了证明.     

Synthesis and aldose reductase inhibitory activity of triazine derivatives possessing acetic acid group.

N-Acetic acid derivatives of 6-aryl-pyrazolo-triazin-4-ones were synthesized for evaluation as new aldose reductase inhibitors. The intrinsic activity of each compound was assessed by measuring the inhibition of enzymatic activity in an isolated pig lens enzyme preparation. All the prepared compounds exhibited a significant in vitro aldose reductase inhibitory effect (10(-6) M less than or equal to IC50 less than or equal to 10(-4) M). Furthermore, biological activity (log 1/IC50) for most of the data sets could be correlated directly to electronic and steric parameters. Finally, spatial configuration of the most active derivative 6c (IC50 = 2 x 10(-6) M) was compared with that of tolrestat and with pharmacophor requirements of the aldose reductase inhibitor site using a molecular modeling system.     

A fluorous-tagged linker from which small molecules are released by ring-closing metathesis

A fluorous-tagged linker for the parallel synthesis of small- and medium-ring and macrocyclic nitrogen heterocycles using ring-closing metathesis is described. The linker was designed such that "cyclization-release" of the cyclic heterocyclic products was coupled with liberation of the active catalyst. The design of the linker was validated using a non-fluorous-tagged model. A wide range of unsaturated alcohols were used as reagents to functionalize a fluorous-tagged sulfonamide, (Z)-{N-[4-(2-(N'-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl)-4-methylsulfonamido)methylallyloxy]but-2-enyl}-2-nitrobenzenesulfonamide, using Fukuyama-Mitsunobu reactions; in each case, fluorous-solid-phase extraction (F-SPE) was used to purify the functionalized linker from the excess reagents. In general, the "cyclization-release" of cyclic products was triggered using a light-fluorous tagged derivative of the Grubbs-Hoveyda second-generation catalyst. After the metathesis step, F-SPE was used to purify released cyclic compounds from the fluorous-tagged linker and the fluorous-tagged catalyst. The scope and limitations of the approach were determined using a range of substrates which probed different aspects of the functionalization and metathesis steps. In the study as a whole, a wide range of small- and medium-ring and macrocyclic nitrogen heterocycles were prepared using polyene and polyenyne metathesis cascades.     

New Facile Route to Synthesize Furo[3,2-e][1,2,4]triazolo[4,3-c]pyrimidine and Furo[3,2-e][1,2,4]triazolo[1,5-c]pyrimidine Derivatives

A new facile route for synthesis of 3-(aryl)-8,9-diphenylfuro[3,2-e][1,2,4]triazolo pyrimidines derivative from the same starting material, 2-amino-4,5-diphenylfuran-3-carbonitrile, has been developed through heterocyclization of the corresponding arylidene-hydrazono-5,6-diphenylfuro[2,3-d]pyrimidine and N-(arylmethylene)-4-imino-5,6-diphenylfuro[2,3-d]pyrimidin-3(4H)-amine under refluxing condition with acetic anhydride followed by air oxidation. The products were obtained in good yield with an easy workup along with the purification of products by a nonchromatographic method. This general synthetic procedure can be extended to the preparation of a wide range of isomeric triazoles using 2-amino 3-carbonitrile bifunctional derivatives.     

2-溴甲基-3-(二溴甲基)喹喔啉的合成研究

以2，3－二（溴甲基）喹喔啉为原料，以N－溴琥珀酰亚胺为溴化试剂合成了2－溴甲基－3－（二溴甲基）喹喔啉（1），1是Diels-Alder环加成反应中形成含杂原子环的C60衍生物的一种重要中间体。通过IR，^1H NMR,^13C NMR,DEPT谱和MS对其进行了结构表征。     

New phenolic compounds from the leaves of Artocarpus heterophyllus

One new 2-arylbenzofuran derivative, artocarstilbene B(1), one new benzaldehyde derivative,(E)-3,5-dihydroxy-4-(3-methylbut-1-enyl)benzaldehyde(2), as well as 18 known compounds(3–20) were obtained from the leaves of Artocarpus heterophyllus. Their structures were elucidated on the basis of extensive spectroscopic techniques including 2D NMR and HR-ESIMS. Many compounds exhibited moderate to weak inhibitory activity against the proliferation of the PC-3, NCI-H460, and A549 cancer cell lines.     

碳F4F6多面体遵循独立四元环原则

为了研究由四元环和六元环构成的碳多面体(F₄F₆多面体)的结构和稳定性之间的关系, 本文采用密度泛函方法对所有C₈~C₆₀之间的F₄F₆多面体进行了系统的计算研究. 结果表明, 能量最低的异构体都满足独立四元环原则, 能量较低的满足四元环比邻惩罚原则. 这两条原则与经典富勒烯所遵循的独立五元环原则和五元环比邻惩罚原则具有同等地位, 能够使研究者仅仅从形貌上就可以对碳F₄F₆多面体的稳定性进行简单高效的判定. 结构分析表明, 四元环之间共用的顶点的锥化角大于其他顶点的锥化角并决定了相应分子的稳定性.     

Carbon polyhedrons formed by squares and hexagons obeying isolated square rule

To gain insight into the structures and stability of F₄F₆ polyhedrons formed by squares and hexagons, a density functional theory study was performed on all isomers of F₄F₆ polyhedrons with sizes from 8 to 60. The calculated results demonstrate that the six squares tend to isolate from each other, i.e. these F₄F₆ polyhedrons obey the isolated square rule. Those isomers with fewer B₄₄ bonds (square-square adjacencies) are more stable than those with more B₄₄ bonds, i.e. they obey square adjacency penalty rule. Both of the two rules in F₄F₆ polyhedrons are in the same status as the isolated pentagon rule and pentagon adjacency penalty rule in F₅F₆ fullerenes and can be used to screen the lowest energy isomers of F₄F₆ polyhedrons as IPR and PAPR do in classic fullerenes. Structural analysis demonstrates that the pyramidalization of carbon atoms at the square-square adjacencies determines the stability of corresponding structures. Electronic Supplementary Material  Supplementary material is available for this article at and is accessible for authorized users. Supported from Southwest University, China (Grant No. SWNUB2005002) and Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment within Ministry of Education, Chongqing University (Grant No. KLVF-2007-5)