Tautomeric structures, electronic spectra, acid-base properties of some 7-aryl-2,5-diamino-3(4-hydroxyphenyazo)pyrazolo[1,5-a]pyrimidine-6-carbonitriles, and effect of their copper(II) complex solutions on some bacteria and fungi

Infrared and electronic spectra were used to investigate the tautomerism of some azo compounds, in both the solid and solution states. It was found that the compounds exist in azo<==>hydrazone tautomeric equilibrium in solid and in solutions. The different bands displayed in the electronic spectra of the compounds in various organic solvents are assigned to the suitable electronic transitions. The solvatochromic behavior of the compounds was investigated by studying their visible spectra in pure and mixed organic solvents. DeltaG and formation constant, Kf, values of the molecular complexes formed in solution have been determined. Effect of concentration of the compounds in DMF and EtOH solutions has been investigated. The basicity and acidity constants of the different compounds were determined from the spectra of these compounds in aqueous-ethanolic solutions of varying pH values. Some complexes of copper(II) with these compounds in solution were tested as for their antibacterial and antifungal activity.     

Enaminothiones of imidazolidine nitroxides,a new route to acetylenic compounds of 3-imidazoline

The title compounds were prepared and their reaction with NaOBr was investigated. Transformation of the enaminothiones and enaminodithiocarboxylates to acetylenic compounds was observed.     

Comparison of sampling efficiency and storage stability on different sorbents for determination of solvents in occupational air

This study describes the sampling efficiency and storage stability of compounds typically present in occupational atmospheres on the sorbents Anasorb CSC, Anasorb 747, and Chromosorb 106. The selection of compounds included in the study contained aliphatic and aromatic hydrocarbons, alcohols, esters, glycol ethers, ketones, and halogenated compounds, thus representing a wide range of chemical and physical properties. The different sorbent tubes were simultaneously exposed to the selected compounds as three different mixtures of solvent vapours in air, and storage both at room temperature and at -22 degrees C was investigated. The sorbent tubes were stored and analyzed at two different laboratories. The sampling efficiencies of all the investigated compounds were excellent on Anasorb CSC and Anasorb 747, while Chromosorb 106 did not give such good results for the most volatile compounds under study. The room temperature storage stability on Chromosorb 106, however, was good for all compounds, although formation of artefacts was observed during storage, a disadvantage that was substantially reduced by storage at -22 degrees C. The room temperature storage stability on Anasorb CSC was good for all compounds except some of the ketones. The room temperature storage stability of these ketones, especially cyclohexanone and 2-butanone, was much better on Anasorb 747, which still showed the same excellent storage stability for the remaining compounds. When stored in a freezer, the storage stability of all compounds, including the ketones, was very good on all sorbents. Among the sorbents under study, Anasorb 747 appears to be the most suitable all-round sorbent for monitoring volatile compounds in occupational air, with satisfactory capabilities regarding both sampling efficiency and storage stability.     

Capillary gas chromatography-atomic emission spectroscopy-mass spectrometry analysis of sulphur mustard and transformation products in a block recovered from the Baltic Sea.

A block of yperite fished up from the Baltic Sea was analysed by gas chromatography coupled with atomic emission spectrometry and mass spectrometry. In the samples of the block about 50 compounds were detected, out of which 30 were identified. The identification of the compounds was performed by using the element chromatograms of the investigated compounds, and the data obtained by mass spectrometric detection. Thiodiglycol was not found among the compounds present in the investigated block. The calculations of the contents of sulphur mustard and some products in the block were performed by an external calibration method using bis(2-chloroethyl) sulphide as the standard. A satisfactory precision of elements determinations was obtained (RSD from 4.4 to 14.3%).     

Chiral HPLC separation and absolute configuration assignment of a series of new triazole compounds

A series of novel chiral triazole compounds were synthesized. They were separated into enantiomers by liquid chromatography on an amylose tris(3,5-dimethylphenylcarbamate) (ADMPC) chiral stationary phase (CSP). The absolute configuration of each enantiomer of the investigated compounds was established by combined use of chemical correlation, chiral HPLC and circular dichroism (CD) spectra analysis methods. The influence of the mobile-phase modifiers and the structure of chiral triazole compounds on the chiral separation and retention were investigated. Reversal of the elution order of some enantiomeric pairs upon using different mobile-phase modifier was observed. The temperature effect on the chiral separation and the thermodynamic properties including enthalpy and entropy change of binding to the ADMPC-CSP were also investigated.     

Biotransformation of beta-nortestosterone by cultured porcine hepatocytes

The metabolism of beta-nortestosterone by porcine hepatocytes was investigated. Initially beta-nortestosterone was rapidly oxidized to norandrostenedione, which was further transformed into a number of more hydrophilic compounds. It is assumed that most of these compounds were glucuronides, considering the effect of beta-glucuronidase treatment. The main product of enzymatic cleavage was investigated by gas chromatography-mass spectrometry but could not be identified until now.     

Polymerization of vinyl and allyl compounds of group iv elements

Summary The free-radical polymerization of some unsaturated compounds of Group IV elements was investigated. The tendency for these compounds to polymerize falls in the order Si > C > Ge > Sn.     

CsCl-NdCl~3-13%HCl(42%HOAc)-H~2O四元体系的研究

研究四元体系CsCl-NdCl~3-13%HCl(42%HOAc)-H~2O(25℃)时的相平衡关系,绘制了相应的溶度图。两平衡体系中均有新相2:1型及1:1型化合物存在,为用Meyer方法合成相应的化合物提供了相化学依据。发现在所研究的体系中,盐酸溶液和醋酸溶液具有"等效介质效应"。     

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.     

化合物YCo12-xTix和YFe12-xTix的结构与磁性

通过X射线衍射分析和磁性测量研究了化合物YCo12-xTix和YFe12-xTix的结构与磁性.结果表明,化合物YCo12-xTix和YFe12-xTix均具有ThMn12型结构,室温下为单轴磁晶各向异性.随着Ti含量的增加,YCo12-xTix的居里温度Tc显著降低,而YFe12-xTix的居里温度Tc几乎不变.所有化合物的饱和磁化强度Ms和磁晶各向异性场Ha随着Ti含量的增加而降低,这可以用双次晶格模型来解释.     

Ring-chain tautomerism of S-acylalkylmercapto-substituted aminoquinoxalines

The ring-chain tautomerism of S-acylalkylmercapto-substituted aminoquinoxalines was studied by means of IR and PMR spectroscopy. It was established that, depending on the substituants,the investigated compounds have open or cyclic structures or exist in the form of mixtures of these forms. Mixtures of diastereomeric forms were detected for two of the investigated compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 114–120, January, 1979.     

Catalysis of Blocked Isocyanate-Hydroxyl-Terminated Polybutadiene Cure Reaction

Abstract

The catalytic activity of three tertiary amines and three organotin compounds in the cure reaction of blocked isocyanate with hydroxyl-terminated polybutadiene was investigated. It was found that the steric factor determines the catalytic activity of the compound. The tin compounds showed higher catalytic activities than the amine compounds. The deblocking catalytic activity of the amine and tin compounds was confirmed by the identification of isocyanate functionality using infrared spectroscopy. The synergistic effect of amine and tin mixed catalysts systems in the deblocking reaction was reported for the first time.     

Transformations of some 6- and 7-substituted 1,2,3-benzothiadiazoles

The preparation of some 6- and/or 7-substituted derivatives of 1,2,3-benzothiadiazole is described. The reactivity of some compounds was investigated in view of the possibility that 1,2,3-benzothiadiazoles may behave as masked diazo compounds. 7-Diazo or diazonium compounds were prepared but no interaction with the thiadiazole part could be observed.     

Comparative study of capillary zone electrophoresis and micellar electrokinetic chromatography for the separation of twelve aromatic sulphonate compounds

Summary Two modes of capillary electrophoresis (CE), capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC), were investigated for the separation of 12 aromatic sulphonate compounds. In CZE, although the voltage applied, the buffer concentration and the pH were optimized for effective separation of the compounds studied, under the best conditions four of the five amino compounds coeluted, as did naphthalene-1-sulphonic acid and naphthalene-2-sulphonic acid. In MEKC, sodium dodecyl sulphate (SDS) and Brij 35 were chosen as the anionic and nonionic surfactants and the effect of the concentration of micelles was examined. The effect of adding methanol as the organic modifier was also investigated with each of these micellar systems. All the analytes, including the isomers, were completely separated by use of MEKC with Brij 35 but when SDS was used only 11 compounds were separated because two amino compounds coeluted.     

Separation of two groups of oestrogen mimicking compounds using micellar electrokinetic chromatography

Two groups of compounds are being investigated due to their reported oestrogen mimicking characteristics in the environment. Separation of phenolic compounds and synthetic oestrogens using micellar electrokinetic chromatography is reported. Photodiode array detection is used for both separations. A standard separation buffer can be used for both groups of compounds including zwitterionic buffer cyclohexylamino-1-propanesulfonic acid, 20 mM at pH 11.5. It was found necessary to include 15% acetonitrile and 25 mM sodium dodecyl sulfate to aid separation and maintain analytes in solution. Optimum separations are achieved using 20 kV with hydrodynamic injection for 5 s. The relative standard deviation (RSD) for reproducibility was investigated for a mixture of phenols and synthetic oestrogens. For these compounds RSD was found to be <0.6% in all cases. Peak efficiencies ranged from 76,000 to 150,000 theoretical plates for different analytes. Application to environmental samples is discussed.     

Selection of optimal pH and solvent composition for the separation of organic acids using three-dimensional diagrams and a computer program

Summary The retention behaviour of different types of organic acids was investigated on an ODS-Hypersil column using eluents of various pH and of various methanol-water ratios. Equations introduced by Horvath and coworkers were fitted onto the experimental data, and the obtained constants were used to calculate the three-dimensional k′-surfaces for the compounds in the investigated pH and solvent composition range. Using the data of the individual surface diagrams the optimal pH and solventg composition was computed for the separation of six selected compounds. To verify the applicability of the above procedure the chromatographic separation of the six compounds was carried out with the predicted conditions, and the chromatogram obtained is presented.     

Reactions of amines with bischloromethyltetramethyldisiloxane and its derivatives

Summary The reaction of bischloromethyltetramethyldisiloxane and its derivatives with mono- and di-amines was investigated, and it was shown that reaction proceeds with formation of cyclic compounds irrespective of the groups attached to the silicon atoms. Six new compounds were synthesized.     

纳米碳酸钙复合的微球体制备及其尺寸控制

利用两亲嵌段共聚物聚苯乙烯-丙烯酸(简称PAS)在水相中构成的空间立体三维框架结构和亲水链聚丙烯酸在水相空间的伸展及其上羧酸基对钙离子的沉积作用,合成了球形纳米碳酸钙复合物,并通过控制共聚物的浓度初步实现了复合物宏观尺寸的调控,制备出粒径约2 μｍ,4 μｍ,8 μｍ的球形纳米复合物。XRD分析结果表明复合物中碳酸钙粒子属方解石型纳米微晶,有较大的晶格畸变率,微晶尺寸随球形复合物的增大反而减小。热分析研究显示,复合物中有机物含量大于12 ％,热分解稳定性的提高认为通过羧酸Ｃａ-Ｏ键合使碳酸钙与聚合物有效复合。     

Flavonol glycosides in leaves of two Diospyros species

Fourteen flavonol glycosides including two new compounds were isolated from the leaves of two Diospyros plants (D. cathayensis and D. rhombifolia). The structures of isolated compounds were determined by spectroscopic analysis. The scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical of the isolated compounds was also investigated.     

A simple atmospheric microwave-excited emissive detector for gas chromatography

An atmospheric pressure microwave-excited emissive argon plasma is evaluated for use as a detector in conventional gas-chromatographic analysis. A range of carbon-, oxygen-, nitrogen- and halogen-containing compounds was investigated in order to optimize the sensitivity, linear working range and plasma operating conditions. For the non-selective determination of carbon-containing compounds, the atomic carbon emission at 247.9 nm was found to be most useful. At this wavelength the sensitivities for all the compounds investigated were directly proportional to the amount of carbon in the compounds. The limit of detection for these compounds at 247.9 nm was 1.94·10^-l0 g of carbon per sec. The atomic lines at 206.2 nm (I) and 470.5 nm (Br) were the best for the selective determination of iodine- and bromine-containing compounds respectively, and a new band emission at 256 nm, characteristic of chlorinecontaining compounds, gave good sensitivity.