Mass spectrometry studies of organolead compounds

The mass spectra of alkyl‐, aryl‐ and chlorinated ‐alkyl, aryl organolead compounds were investigated. Positive and negative ion mass spectra of these compounds were recorded using conventional electron impact conditions. In common with the analogous tetraalkyltin and tetraalkylgermanium compounds, tetrabutyllead produced no negative ion spectra under these conditions. The spectra were also examined by tandem mass spectrometry in order to establish reaction mechanisms for these compounds. Fragmentation patterns of seven organolead compounds, based on precursor–product ion relationships, are proposed. Copyright © 2001 John Wiley & Sons, Ltd.     

氰基乙烯基苯胺衍生物的电化学行为

本文利用循环伏安法研究了电子给-受体模型化合物——氰基乙烯基苯胺衍生物的电化学行为,并对推电子取代基团—NH_2和—N(CH_3)_2与吸电子取代基团氰基乙烯基对化合物电化学行为的影响进行了较为详细的讨论.提出了这些化合物的电氧化态和电还原态的结构,通过分析比较叔、仲和伯自由基对化合物电化学行为的影响,探讨了电极反应机理.     

三(2-甲基-2-苯基丙基)锡芳氧乙酸酯的合成

三（２－甲基－２－苯基丙基）锡芳氧乙酸酯的合成刘宝殿,宁志刚,朱东升,包明（东北师范大学化学系,长春,１３００２４）关键词三（２－甲基－２－苯基丙基）锡芳氧乙酸酯,三（２－甲基－２－苯基丙基）氢氧化锡,芳氧乙酸,杀螨活性１９６６年Ｒｅｉｃｈｌｅ［１］...     

硝基咪唑化合物结构与性质的理论研究

采用密度泛函理论B3LYP方法在6-311G(d,p)水平上, 对10种硝基咪唑化合物进行了理论计算: 几何优化结果显示所有化合物均无虚频, 为势能面上的稳定结构. 基于自然键轨道理论和三维静电势图, 分析了稳定结构的成键情况、咪唑环上的共轭性及硝基咪唑化合物的反应性. 理论估算了10种化合物的标准气态生成热和密度, 最后采用VLW方程计算了这些化合物的爆速、爆压, 其爆速在8.7和9.5 km/s之间. 结果表明: 咪唑环上有一定的芳香性, 所设计的系列硝基咪唑化合物能量高, 其中三硝基咪唑化合物是最有潜力的含能材料候选物.     

A Study of the Silylation of 1,8-Dihydroxynaphthalene

Twelve compounds each having a six membered Si-contained heterocycle, have been successfully synthesized. Of these eleven compounds have never been reported in the literature. The structures were confirmed by Spectral analysis and elementary analysis. The stability and properties of these compounds is also discussed.     

异色满酮-4及其衍生物的合成IX异香豆素并杂环化合物的合成

本文通过3, 4-二氢异苯并吡喃酮-4和其β-二酮衍生物的缩合反应, 合成出3, 4-二氢异苯并吡喃并吲哚、并喹啉、并吡唑和并嘧啶类化合物, 并进一步氧化成标题化合物。所合成的新化合物均经核磁共振光谱红外光谱及元素分析证明其分子结构。     

Agostic bonds in cyclometalation

Cyclometalation reactions proceed very easily with one step reaction between metal compounds and substrates having a heteroatom such as O, S, N, P and As. However, under mild reaction conditions, many agostic compounds which are intermediates in these cyclometalation reactions, can be isolated. The metal compounds used for the formation of these agostic intermediates are both transition metal and main group metal compounds. The substrates are nitrogen-containing compounds, phosphorus-containing compounds, oxygen-containing compounds and sulfur-containing compounds. These agostic intermediates are mainly δ-C-H agostic compounds, some are γ-C-H agostic compounds and very few are ?-C-H-agostic compounds. The agostic intermediates are prepared, usually, under mild reaction conditions in the cyclometalation reaction. These agostic compounds are also prepared from cyclometalation reaction products, e.g., by the protonation, irradiation, and elimination of ligand molecules by vacuum, inert gas current, dehydration with a molecular sieves 4A, etc. Some agostic compounds are utilized for preparation of stable catalysts, e.g., hydrogenation catalysts.     

飞行时间二次离子质谱(TOF-SIMS)结合化学衍生法分析杂环新化合物的结构

飞行时间二次离子质谱(TOF-SIMS)分析了难挥发的杂环新化合物咪唑啉硫氰酸盐及其三种衍生物, 确认出很强的氢离化及银离化准分子离子峰, 通过对各种衍生物谱图的对照分析, 确认出较强的含有结构特征的碎片离子峰, 并对该化合物在离子轰击下的裂解规律作了分析, 支持了对该新化合物结构的鉴定。     

Influence of fluorine substituent on the mesomorphic properties of five-ring ester banana-shaped molecules

The synthesis and characterization of more than a hundred achiral compounds composed of banana-shaped molecules and belonging to eleven different homologous series are reported. All these symmetrical five-ring compounds are esters and are derived from resorcinol. The compounds have been systematically substituted by fluorine on the phenyl rings of the arms of these banana-shaped molecules. The mesophases exhibited by these compounds have been characterized using a combination of polarized light optical microscopy, differential scanning calorimetry and X-ray diffraction studies. Electro-optical investigations have been carried out on several compounds and both ferroelectric and antiferroelectric properties are observed. The influence of the position of the fluorine substituent on the nature of the mesophase obtained has been examined.     

The identification of new ATAD2 bromodomain inhibitors: the application of combined ligand and structure-based virtual screening

Ligand-based virtual screening (LBVS) and structure-based virtual screening (SBVS) approaches were used to identify new inhibitors for ATAD2 bromodomain. The LBVS approach was used to search 23,129,083 clean compounds to identify compounds similar to an active compound with reported pIC₅₀ equal to 7.2. Based on LBVS results, 19 compounds were selected. To perform SBVS, by applying nine filters on 23,129,083 clean compounds, 1,057,060 compounds were selected. After performing SBVS on these selected compounds with idock software, 16 compounds with the lowest binding energies were selected. More accurate molecular docking analysis was performed on these 35 selected compounds by using iGEMDOCK software and six of them with the lowest binding energies were selected as hit compounds. These compounds were zinc36647229, zinc77969074, zinc13637358, zinc77971540, zinc12991296 and zinc19374204.     

三苯基锡芳氧乙酸酯的合成和表征

三苯基锡芳氧乙酸酯的合成和表征刘宝殿，包明，张景萍（东北师范大学化学系、东北师范大学分析测试中心，长春，１３００２４）关键词芳氧乙酸，三苯基锡芳氧乙酸酯，合成，生物活性三苯基醋酸锡和三苯基氢氧化锡是防治甜菜褐斑病的有效药剂［１］．芳氧乙酸及其酯也具有...     

Raman spectroscopic characterisations and analytical discrimination between caffeine and demethylated analogues of pharmaceutical relevance

The FT Raman spectrum of caffeine was analysed along with that of its demethylated analogues, theobromine and theophylline. The similar but not identical structures of these three compounds allowed a more detailed assignment of the Raman bands. Noticeable differences in the Raman spectra of these compounds were apparent and key marker bands have been identified for the spectroscopic identification of these three compounds.     

Cytostatic action of triazole and oxazolidinone derivatives

We synthesized a number of derivatives of 1,2,3-benzotriazole, 1,2,4-triazole, and oxazolidine-2-one derivatives, among which compounds suppressing the growth of the tumor cells HeLa and H1299 were revealed. The studies of the effect of these compounds on the cell cycle and activity of caspase dependent degradation of poly(ADP-ribose) polymerase showed that these compounds at the IC₅₀ doses exhibit cytostatic effect on tumor cells. In the MCF7 cells, these compounds induce an increase in expression of the tumor suppressor p53.     

Self-assembly of azo molecules to mesogenic phasmid-like materials through inter-molecular hydrogen bonding

A series of acid-functionalised new azo compounds was synthesised and characterised. The constituent molecules self-organise to form dimers through inter-molecular hydrogen bonding, resulting in phasmid-like compounds. This was once considered to be a promising molecular architecture to form biaxial nematic phases. The mesomorphic properties of these new azo compounds were studied using polarising optical microscopy, differential scanning calorimetry and X-ray diffraction. Investigations revealed that these compounds form nematic and columnar mesophases. A few more compounds were synthesised by replacing the??N=N- linkage in these compounds with??CH=N- and??COO- to study the effect of different linkages on the mesomorphic properties in such molecular systems. All were found to be liquid crystalline. The compounds with a??N=N- linkage are more conducive to mesomorphism and are thermally very stable. The effect of number of alkoxy chains on the mesomorphic properties of this system was also studied. To the best of our knowledge, at present, only a handful of phasmid-like mesogenic compounds, formed by the intermolecular hydrogen bonding, are known.     

FIVE-MEMBERED RING COMPOUNDS IN ORGANOMETALLIC INTRAMOLECULAR-COORDINATION COMPOUNDS

Organometallic intramolecular-coordination five-membered ring compounds show high reactivity and high selectivity. Therefore, these many compounds have been synthesized since around mid 1960s. More than 50 kinds of metals are found as the metal elements, and these compounds are very widely used as intermediates and catalysts for organic syntheses.     

Influence of fluorine substituent on the mesomorphic properties of five-ring ester banana-shaped molecules

The synthesis and characterization of more than a hundred achiral compounds composed of banana-shaped molecules and belonging to eleven different homologous series are reported. All these symmetrical five-ring compounds are esters and are derived from resorcinol. The compounds have been systematically substituted by fluorine on the phenyl rings of the arms of these banana-shaped molecules. The mesophases exhibited by these compounds have been characterized using a combination of polarized light optical microscopy, differential scanning calorimetry and X-ray diffraction studies. Electro-optical investigations have been carried out on several compounds and both ferroelectric and antiferroelectric properties are observed. The influence of the position of the fluorine substituent on the nature of the mesophase obtained has been examined.     

手性-3, 5-二取代-1', 2', 4'-三唑-[3', 4'-b]-2, 4-二氢间 噻二嗪的合成及 生物活性

以3-芳基-5-巯基-1,2,4-均三唑为原料,和甲醛及S-(-)-α-苯乙胺在酸催化作用下合成了6种新的化合物。研究了合成反应的条件。通过元素分析、IR、^1HNMR、和MS确证了其结构,测定了比旋光度和生物活性。结果表明,一些化合物具有一定的抗菌活性。     

Heterocyclic triptycenes : Synthesis and ultraviolet spectroscopy

The synthesis of some heterocyclic triptycenes is reported. A study of the UV spectra of these and analogous compounds was undertaken. Two series of compounds were prepared: 9,10-bridged anthracene compounds and 5,12-bridged naphthacene compounds. The results from these studies alone are inconclusive. However if calculations are made, based on interannular π-π interactions between the aromatic rings in these systems, the calculated N → V₁ transitions and longest wavelength absorption maxima give a straight line when plotted.     

HPLC-DAD-qTOF Compositional Analysis of the Phenolic Compounds Present in Crude Tomato Protein Extracts Derived from Food Processing

The conversion of raw fruits and vegetables, including tomatoes into processed food products creates side streams of residues that can place a burden on the environment. However, these processed residues are still rich in bioactive compounds and in an effort to valorize these materials in tomato by-product streams, the main aim of this study is to extract proteins and identify the main phenolic compounds present in tomato pomace (TP), peel and skins (TPS) by HPLC-DAD-ESI-QTOF. Forty different phenolic compounds were identified in the different tomato extracts, encompassing different groups of phenolic compounds, including derivatives of simple phenolic acid derivatives, hydroxycinnamoylquinic acid, flavones, flavonones, flavonol, and dihydrochalcone. In the crude protein extract (TPE) derived from tomatoes, most of these compounds were still present, confirming that valuable phenolic compounds were not degraded during food processing of these co-product streams. Moreover, phenolic compounds present in the tomato protein crude extract could provide a valuable contribution to the required daily intake of phenolics that are usually supplied by consuming fresh vegetables and fruits.     

5,5′-二(对-取代苯基)-2,2′-联噁唑的合成及其光性能研究

合成了8种5,5′-二(对-取代苯基)-2,2′-联噁唑,其中6种是未见报道的新化合物。讨论了它们的结构与光性能间的关系,并比较了它们和5,5′-二(对-取代苯基)-2,2′-联-1,3,4-噁二唑的光性能。