Convenient one-pot synthesis of thiobarbituro-quinoline derivatives via catalyst-free multicomponent reactions in water

A one-pot, three-component condensation reaction of 8-quinolinol, 2-thiobarbituric acid and isatins or aldehydes in water to give novel barbituroquinoline derivatives for the first time, is described. The reaction is free of catalysts and toxic solvents, operating under mild conditions and allows for ease of product isolation, making it more environmentally friendly and suitable for large-scale operations.     

比较研究山姜素和豆蔻明与人-γ球蛋白的相互作用

将互为同分异构体的两种植物药活性组分山姜素和豆蔻明作为研究对象,应用荧光光谱法、紫外光谱法以及红外光谱法并结合分子对接技术首次对这两种黄酮类化合物与人-γ球蛋白(Human gammagobulin,HG)的相互作用进行了详细研究.荧光光谱法的研究结果表明,这两种药物均与HG有较强的相互作用(结合常数均在104～105之间);山姜素对HG表现为静态猝灭机理,而豆蔻明对HG表现出非常少见的动态猝灭机理.比较不同温度(298,308和318K)下两种药物与蛋白相互作用的结合参数都有所差别,维持药物-HG体系的作用力也不同.山姜素和豆蔻明分子与HG色氨酸残基间的结合距离r值(分别为3.88和4.52nm)都小于7nm,说明发生了能量转移.同步荧光与红外光谱法定性及定量地研究了药物对HG二级结构的不同影响程度.两种分子对接结果表明了这两种药物与HG的结合区域.     

9-苯基芴-4-三苯胺电致发光材料的光电性质

采用HF方法和DFT/B3LYP方法对一种新型的含芴三苯胺,即9-苯基芴-4-三苯胺有机化合物进行了基态结构全优化,CIS方法获得分子最低激发态结构,并采用TD-DFT方法计算分子的吸收光谱和发射光谱.计算结果表明,该分子从基态到激发态的跃迁,几何结构变化主要表现在分子中心三苯胺中苯环和N原子之间的二面角上,吸收及发射光谱的计算结果与实验值一致,吸收光谱为324.52nm,发射光谱为379.01nm,荧光寿命较长,为60.6637ns,是优良的典型蓝色有机电致发光材料.     

The structure and the potential energy function of AlSO(C_S,X~2A″)

By using the B3P86/aug-cc-pvtz method,the accurate equilibrium geometry of the AlSO(CS,X2A″) molecule has been calculated and compared with available theoretical values.The obtained results show that the AlSO molecule has a most stable structure with bond lengths of R OAl = 0.1864 nm,R OS = 0.1623 nm,R AlS = 0.2450 nm,together with a dissociation energy of 13.88 eV.The possible electronic states and their reasonable dissociation limits for the ground state of the AlSO molecule were determined based on the principle of atomic and molecular reaction statics.The analytic potential energy function of the AlSO molecule was derived by the many-body expansion theory and the contour lines were constructed for the first time,which show the internal information of the AlSO molecule,including the equilibrium structure and stable point.The analysis demonstrates that the obtained potential energy function of AlSO is reasonable and successful and the present investigations provide important insights for further study on molecular reaction dynamics.     

Applications of the representative points in statistical simulations

The paper gives a new approach to statistical simulation and resampling by the use of number-theoretic methods and representative points. Resempling techniques take samples from an approximate population. The bootstrap suggests to use a random sample to form an approximate population. We propose to construct some approximate population distribution by the use of two kinds of representative points, and samples are taken from these approximate distributions. The statistical inference is based on those samples. The statistical inference in this paper involves estimation of mean, variance, skewness, kurtosis, quantile and density of the population distribution. Our results show that the new method can significantly improve the results by the use of Monte Carlo methods.     

Existence and stability of periodic solutions of high-order Hopfield neural networks with impulses and delays

By using the continuation theorem of coincidence degree theory and constructing suitable Lyapunov functions, the global exponential stability and periodicity are investigated for a class of delayed high-order Hopfield neural networks (HHNNs) with impulses, which are new and complement previously known results. Finally, an example with numerical simulation is given to show the effectiveness of the proposed method and results. The numerical simulation shows that our models can occur in many forms of complexities including periodic oscillation and the Gui chaotic strange attractor.     

A new naphthoquinone and other antibacterial constituents from the roots of Xanthium sibiricum

Reinvestigating the chemical constituents of the roots of Xanthium sibiricum led to the isolation of a new naphthoquinone (1), together with 13 known compounds (2–14). Their structures were elucidated by using spectroscopic analyses, including HR-ESI-MS, 1D and 2D NMR, and by comparing their NMR data with those of related compounds. Compound 1 showed moderate antibacterial activity against Escherichia coli, Bacillus subtilis, Micrococcus tetragenus and Staphylococcus aureus, while 6 and 12 showed stronger antibacterial activity than the positive control ciprofloxacin against E. coli, with minimum inhibitory concentration values of 0.17 and 0.35 μg/mL, respectively.     

New Cu(I) Coordination Complexes Based on Tetrathiafulvalene Substituted Triazol‐pyridine Ligand: Synthesis,Properties and Theoretical Studies

Two Cu(I) complexes based on the thioethyl‐bridged triazol‐pyridine ligand with tetrathiafulvalene unit (TTF‐TzPy, L ), [Cu(I)(Binap)(L)]BF₄ ( 5 , Binap=2,2’‐bis(diphenylphosphino)‐1,1’‐binaphthyl) and [Cu(I)(Xantphos)(L)]BF₄ ( 6 , Xantphos=9,9‐dimethyl‐4,5‐bis(diphenylphosphino)‐xanthene), have been synthesized. All new compounds are characterized by elemental analyses, ¹H NMR and mass spectroscopies. The complex 5 has been determined by X‐ray structure analyses which shows that the central copper (I) ion assumes distorted tetrahedral geometry. The photophysical, computational and electrochemical properties of L and 5 ‐ 6 have been investigated. The most representative molecular orbital energy‐level diagrams and the spin‐allowed singlet? singlet electronic transitions of the three compounds have been calculated with density functional theory (DFT) and time‐dependent DFT (TD‐DFT). The luminescence bands of Cu(I) complexes 5 ‐ 6 have been assigned as mixed intraligand and metal‐to‐ligand charge transfer ³(MLCT+π→π^*) transitions through analysis of the photophysical properties and DFT calculations. The electrochemical studies reveal that 5 ‐ 6 undergo reversible TTF/TTF^+?/TTF²⁺ redox processes and one irreversible Cu⁺→Cu²⁺ oxidation process.     

Structure and Absolute Configuration of Aspergilumamide A,a Novel Lumazine Peptide from the Mangrove‐Derived Fungus Aspergillus sp.

A novel lumazine peptide, aspergilumamide A ( 1 ), as well as a known analog penilumamide ( 2 ), were isolated from the mycelia of a marine‐derived fungus Aspergillus sp. (33241), obtained from the mangrove Bruguiera sexangula var. rhynchopetala collected from the South China Sea. The structure of 1 was identified by comprehensive spectroscopic analysis, including 1D‐ and 2D‐NMR, ESI‐MS, and MS/MS experiments. The absolute configuration of 1 was determined by Marfey's method.