Detection of afobazole and its major metabolites using capillary gas chromatography-mass spectrometry

The possibility of detecting a target compound using Gas Chromatography-Mass Spectrometry has been demonstrated and the structure of these compounds has been confirmed. The possibility of sorption of these compounds in the chromatographic system has been analyzed. Results obtained using various sample injection modes have been compared. A highly sensitive method for detecting micromolar amounts of the compounds under investigation in samples with large volumes has been developed. The detection limits of the compounds studied equaled 5 × 10^?10 g in a sample of the model solution.     

Radical polymerization as an indicator reaction for determination of organic compounds

Polymerization of methyl methacrylate (MMA) and 4-vinylpyridine (VP) has been carried out in an aqueous solution in the presence of the initiating system persulfate-tetramethylethylenediamine. The reaction rate has been monitored by measuring the light absorbance of the suspension of the resulting polymer. The effect of 26 model organic compounds on the polymerization rate has been studied. It has been shown that the VP polymerization is inhibited by a smaller number compounds (9 compounds) than the MMA polymerization (22 compounds), which indicates that the former reaction has better selectivity, whereas the determination of model compounds using the MMA polymerization reaction is more sensitive. This is explained by the lower chain growth rate constant for VP vs. MMA and different stationary concentrations of radicals in the systems. The use of these indicator polymerization reactions makes it possible to distinguish some closely related compounds, e.g., 1,4-benzoquinone and 9,10-anthraquinone (MMA reaction) or dinitrophenol and 4-nitrophenol or phenol (VP reaction). Determination of ascorbic acid in a pharmaceutical formulation has been carried out.     

Developing an antituberculosis compounds database and data mining in the search of a motif responsible for the activity of a diverse class of antituberculosis agents

A novel data mining procedure to look for new antitubercular agents and targets as well as to find a minimum common bioactive substructure (MCBS), has been reported here. The methodology extracts MCBS, both across the diverse chemical classes and within the particular chemical class, known to be present in the various marketed drugs alongside antimycobacterial compounds with known MICs. For this purpose a small in-house database of compounds has been created, for which MICs against Mycobacterium are known. The compounds have been collected from literature available on the synthetic compounds, having known MICs against Mycobacterium tuberculosis. An elaborate HQSAR (Hologram QSAR) study has been attempted to extract active fragment from a diverse class of compounds, in combination with the clustering technique to select a homogeneous group of compounds having good a profile toward the activity. The 2D pharmacophore (the 2D fragments extracted from HQSAR) has been validated searching the database. It has been found further that this validated 2D pharmacophore could be used for searching the orphan target in Mycobacterium effectively.     

Mass spectral fragmentation reactions of angiotensin-converting enzyme (ACE) inhibitors

A variety of mass spectrometric techniques have been employed in the study of a series of structurally similar compounds used in the treatment of hypertension. The compounds, known collectively as angiotensin-converting enzyme (ACE) inhibitors, all share the amino acid residue proline or some variant thereof, as a common structural element. The gas phase fragmentation behavior of these compounds has been explored systematically using various instruments and techniques. An interesting dissociation process (rearrangement) unique to one of the compounds, lisinopril, has been investigated using isotopic labeling experiments and exact mass measurements. The general nature of the process has been probed through both the positive and negative ion analyses of fourteen related compounds exhibiting structural homology.     

Determination of organometallic compounds by capillar gas chromatography – inductively coupled plasma mass spectrometry

The separation and detection of volatile organometallic compounds containing tin, iron, and nickel has been achieved using capillary GC–inductively coupled plasma–mass spectrometry (capillary GC-ICP-MS). Detection limits range from 3.0 to 7.0 pg/s. The presence of volatile organotin compounds in a harbor sediment has been confirmed. The retention range of the organometallic compounds analyzed by capillary GC-ICP-MS has been extended considerably beyond that possible in earlier studies (retention indices up to 3400).     

Use of semiconductor oxide films for the detection of volatile organic compounds in the gas phase

A new type of flow-sensitive detectors of volatile organic compounds based on tin dioxide films modified by transition metal oxides has been proposed. The change on the film electric conductivity upon its contact with a flow of carrier gas containing a detectable compound has been used as an analytical signal. Dependences of analytical signals for some organic compounds on the temperature and film composition have been studied. Gas-chromatographic separation of model mixtures using a thermal catalytic detector has been performed. The possibility of the identification of organic compounds by the relationship between the analytical signals of two films of different compositions has been demonstrated.     

某些结构受阻氧鎓盐的吸收和荧光

氧锅盐是一类带正电行的杂环化合物，作为一种合成中间体，氧锅盐在有机合成方面已得到广泛的应用［’］近年来人们对其发光和光谱性质的研究也给予足够的注意．这是由于很多氧锅盐化合物有着很强的荧光发射【’J，并且其中有些已被用作激光染料出或Q一开关材料卜1由于氧钠盐强烈的亲电特性，因而它在聚乙烯咋哇电照相体系中也受到特殊的注意，即通过它来捕获电子和诱导分子内正空穴向负电极方向迁移问染料分子的刚性化对激发分子的弛豫过程往往会带来巨大的影响，如非刚性化分子会通过分子内自由旋转使分子在激发态的弛豫过程中形成不同的…     

环境内分泌干扰素分析方法进展

本文详细介绍了国内外环境内分泌干扰素的分析研究进展。着重介绍了环境样品的预处理方法，并进行了比较和评价，对不同环境样品中内分泌干扰素的分析检测方法进行了介绍。     

Estimation of phospholipophilicity of 1-[3-(arylpiperazin-1-yl)-propyl]-pyrrolidin-2-one derivatives on immobilized artificial membrane stationary phase and its correlation with biological data

A molecule library containing 42 1-[3-(arylpiperazin-1-yl)-propyl]-pyrrolidin-2-one derivatives has been designed and synthesized. The phospholipophilicity of the obtained compounds has been determined using immobilized artificial membrane high-performance liquid chromatography (IAM-HPLC). The performed analysis allowed the calculation of log k(we) values for each of the tested compounds. Experimental phospholipophilicity data (log k(we)) has been compared with the affinity of the tested compounds to alpha(2)-adrenoceptors. Performed quantitative structure-activity relationship studies indicated that, for the tested compounds, there are dependences between affinity for alpha(2)-adrenoceptors and their log k(we) values. The obtained results confirmed that the applied chromatographic IAM-HPLC method could be useful in fast characterization of the phosholipophilicity of structurally closely related compounds as well as for larger series of compounds, such as drug candidates. It could also be used as a tool for further research into this group of compounds.     

某些结构受阻氧鎓盐的吸收和荧光

A series of pyrylium compounds with different structures have been synthesized. The photophysical behavior of these compounds has also been measured. Results show that the structures of compounds and the polarities of solvents make great effects on the photophysical behaviors of compounds, especially when the structures of compounds are hindered. It indicats that the intramolecular rotation relaxation of compounds in excited state in closely related to the fluorescence quantum yields of compounds.     

Synthesis and Biological Activity of 4-Aryl-<Emphasis Type="Italic">N</Emphasis>-(5,6-R-benzo[<Emphasis Type="Italic">d</Emphasis>]thiazol-2-yl)- 2-hydroxy-4-oxobut-2-enamides

The interaction of 5-arylfuran-2,3-diones with 5,6-R-benzo[d]thiazole-2-amines has resulted in 4-aryl-N-(5,6-R-benzo[d]thiazol-2-yl)-2-hydroxy-4-oxobut-2-enamides. The products structure has been confirmed by means of IR, NMR, and ¹H NMR spectroscopy as well as mass spectrometry. Analgesic and antimicrobial activities of the prepared compounds have been studied; acute toxicity of the most active compounds has been determined. The relationship between the structure and biological activity of the obtained compounds has been elucidated. The compounds acting comparably or better than the reference drugs have been found.     

Analytical multimethod for the determination of low volatile organic pollutants in sediments and sewage sludges

By means of selected target compounds with different physical and chemical properties an analytical method has been developed for the analysis of a wide variety of low volatile xenobiotics in sediments and sewage sludges. After an exhaustive extraction at different pH values first high molecular matrix compounds have been separated by GPC. Fractionation of the samples into five separate groups of substances has been performed by successive column chromatography using deactivated alumina and silica gel. For the determination of phenols a derivatization step with pentafluorobenzolychloride has been incorporated into the sample preparation. Removal of sulphur and aliphatic hydrocarbons has been accomplished by an additional clean up with TBA-sulfite reagent and silica gel. Recoveries of the most target compounds exceeded 80%.     

Synthesis, structure, and properties of the Cu(II) coordination compounds with the pyruvic acid nicotinoyl and isonicotinoyl hydrazones

New coordination compounds of Cu(II) and hydrazones of nicotinic and isonicotinic acids have been prepared. The complexes isolated have been studied by elemental analysis, thermogravimetric analysis, magnetic susceptibility measurements, IR, diffuse reflectance, and EXAFS spectroscopy. The geometry of the compounds has been determined and the type of the ligands coordination has been revealed. Antibacterial activity of the complexes has been studied.     

咪唑啉酮类除草剂的三维构效关系研究

从三维角度出发,采取不同的构象搜索方法得到了咪唑酮类化合物分子的活性构象。利用比较分子场分析方法进一步证实了模板分子构象的正确性。并从静电场、立体场及活性关系等方面进行了三维定量构效关系研究,得到了具有较强预测能力的QSAR模型。     

Synthesis and ring-chain tautomerism of substituted 4-hydroxy-hexahydropyrimidine-2-thiones

The synthesis of a number of substituted 4-hydroxyhexahydropyrimidine-2-thiones has been effected. The prototropic ring-chain tautomerism of compounds of this type in chloroform solution has been investigated by IR spectroscopy. The dependence of the relative stability of the cyclic tautomeric forms on the structures of the compounds studied has been elucidated.     

1,3,5-三芳基-2-吡唑啉化合物光物理行为的研究

合成了一组带不同取代基的三芳基吡唑啉化合物,对它们在不同极性溶剂中的光物理行为(如荧光量子产率,荧光寿命等)进行了测定指出:这类化合物在光的激发下除存在有分子内共轭条件下的电荷转移行为外,还存在着分子内非共轭条件下的电子转移,本工作还以三芳基吡唑啉化合物为猝灭剂对氧鎓盐的荧光猝灭能力进行了研究,并对所得结果作了讨论。     

Thermal characterization of tetramethylphosphonium perchlorate, -nitrate and -picrate

Tetramethylphosphonium perchlorate, -nitrate and -picrate have been characterized thermally employing differential thermal analysis and thermogravimetric techniques. The thermal stability of these compounds is found to be in the order, perchlorate>nitrate>picrate. A similar trend is stability has been obserbed in the case of the corresponding ammonium compounds. These observations have been explained in terms of the dissociation of these salts prior to their decomposition. Explosion sensitiveness of these compounds has been determined by explosion delay measurements which also seem to indicate the same order of relative stability. The ammonium compounds appear to be more stable than their phosphonium counterparts.     

反相薄层色谱法测定1-1,2,4-三唑类杀菌剂的疏水性

1-1 ,2 ,4-三唑类农药是本世纪 60年代初期发展起来的新型杀菌剂 ,具有广谱、高效和内吸等优点 ,一直是农药研究的热门课题 [1] .多年的研究表明 ,其疏水性与活性有很好的相关性 ,因此快速准确地测定其疏水性显得十分重要 .与传统的振荡方法测定化合物的疏水性相比 ,反相高效液相色谱法( RP-HPLC) [2～ 4 ] 和反相薄层色谱法 ( RP-TL C) [5,6 ] 简单、快速、经济 ,所需样品量很少 ,对样品纯度要求也不高 .尤其是薄层色谱法所需仪器简单 ,耗时更短 .本文以甲醇 -水混合物为展开剂测定了我们合成的 2 3种新型三唑类化合物在 C2高效薄层板…     

Electrical Conduction of Some Fe3S3 Ring Compounds

M3S3 cluster six-membered ring compounds are very interesting compounds liking aromatic benzene, and Cu, Pd, B and so on can also form M3S3 cluster besides Fe. [1,2] In recent years electrical conduction of some metal com plexes has been studied. [3,4] The study of electrical conduction through DNA molecules has illustrated that DNA is a semiconductor, but its principle of electrical conduction has not been revealed. [5,6] Electrical conduction of artificial synthesized Fe-S cluster compounds has not been reported. We hope to infer the function on electrical conduction of metal active centers of iron-sulfur proteins through study of electrical conduction of Fe3S3 ring compounds, paving the way for the discovery of new advanced biological functional materials.