NEW APPROACHES TO THE SYNTHESIS OF ORGANOPHOSPHORUS COMPOUNDS

Abstract

The past two decades have brought us a snowballing development of organophosphorus chemistry. Indeed organophosphorus compounds have found wide practical application (in agriculture, petroleum industry, as drugs, etc.) and continue to afford promising objects for the study of theoretical matters such as tautomerism, ambiphilicity, ambidenticity, and other problems of organic chemistry. On the other hand, however impressive this progress may be, the search for new methods of synthesis, improving the known methods and forecasting new types of organophosphorus compounds remain as challenging problems as before.     

A Convenient Method for Dethioacetalization of 1,3-Dithiolanes and 1,3-Dithianes Using Benzyltriphenylphosphonium Peroxymonosulfate in Aprotic Solvent

Benzyltriphenylphosphonium peroxymonosulfate in the presence of bismuth chloride was found to be an efficient and mild reagent for the dethioacetalization of 1,3-dithiolanes and 1,3-dithianes to the corresponding carbonyl compounds under aprotic conditions.     

吸附/一级热解吸/气相色谱联用测定室内空气中的挥发性有机物

本文以高聚物TenaxTA动态吸附,一级热解吸/毛细管气相色谱法联用测定室内空气中的挥发性有机物。优化了热解吸温度和热解吸时间,建立了苯、甲苯、乙酸正丁酯、乙苯、对二甲苯、苯乙烯、邻二甲苯、正十一烷等8种典型有机污染物的外标定量曲线,各化合物线性范围为103,相关系数R为0.9983～0.9999,最低检出浓度可达2×10-4mg/m3;考察了方法的重复性、热解吸率和残留率,并分析了实际空气样品。     

(Nd1-xYx)3Fe27.31Ti1.69化合物的结构与磁性研究

制备了(Nd1-xYx)3Fe27.31Ti1.69(0≤x≤0.6)系列化合物,通过X射线衍射和磁性测量等手段研究了它们的结构和磁性.这些化合物均为Nd3(Fe,Ti)29型结构,A2/m空间群.化合物晶胞体积随Y含量增加而单调减少,居里温度Tc随Y含量增加略有降低,说明化合物的居里温度主要由Fe-Fe之间的交换相互作用所决定.温度为5K时,饱和磁化强度Ms随Y含量的增加而单调降低,与一个简单的稀释模型预期结果一致.所得化合物在低温下均发生自旋重取向,自旋重取向温度Tsr随Y含量增加而单调降低,从x=0时的232K减小到x=0.6时的121K.基于磁晶各向异性的研究结果确定了所得化合物的自旋相图.     

Kurze Originalarbeiten: Zur Reindarstellung von tritiummarkierten Pyrimidinderivaten 1. Mitt. Markierung von 5-Hydroxyuracil und 5-Aminouracil durch katalytischen II-T-Austausch

Zur Vervollkommung der strahlenchemischen Technologie für die Herstellung einiger für die Industrie wichtiger silizium-organischer Monomere und zur Durchführung von Forschungs-arbeiten auf diesem Gebiet wurde eine Pilot-Anlage unter Verwendung des Elektronenbeschleunigers EU-0,4 geschaffen, der im Physikalisch-chemischen Forschungsinstitut ?L. J. Karpow“ auf der Grundlago des Rōntgendefektoskopie-Gerātes RUP-400-5 entwickelt wurde.     

Simultaneous Determination of Multicomponents in Air Toxic Organic Compounds Using Artificial Neural Networks in Ftir Spectroscopy

The application of Artificial Neural Networks (ANNs) for nonlinear multivariate calibration using simulated FTIR data was demonstrated in this paper. Neural networks consisting of three layers of nodes were trained by using the back-propagation learning rule. Since parameters affect the performance of the network greatly, simulated data were used to train the network in order to get a satisfactory combination of all parameters. The mixtures of four air toxic organic compounds whose FTIR spectra are overlapped were chosen to evaluate the calibration and prediction ability of the network. The relative standard error (RSD%), the percent standard error of prediction samples (%SEP) and the percent standard error of calibration samples (%SEC) are used for evaluating the ability of the neural network.     

Production of Siderophores by an Apple Root-Associated Streptomyces ciscaucasicus Strain GS2 Using Chemical and Biological OSMAC Approaches

Apple Replant Disease (ARD) is a significant problem in apple orchards that causes root tissue damage, stunted plant growth, and decline in fruit quality, size, and overall yield. Dysbiosis of apple root-associated microbiome and selective richness of Streptomyces species in the rhizosphere typically concurs root impairment associated with ARD. However, possible roles of Streptomyces secondary metabolites within these observations remain unstudied. Therefore, we employed the One Strain Many Compounds (OSMAC) approach coupled to high-performance liquid chromatography-high-resolution tandem mass spectrometry (HPLC-HRMSⁿ) to evaluate the chemical ecology of an apple root-associated Streptomyces ciscaucasicus strain GS2, temporally over 14 days. The chemical OSMAC approach comprised cultivation media alterations using six different media compositions, which led to the biosynthesis of the iron-chelated siderophores, ferrioxamines. The biological OSMAC approach was concomitantly applied by dual-culture cultivation for microorganismal interactions with an endophytic Streptomyces pulveraceus strain ES16 and the pathogen Cylindrocarpon olidum. This led to the modulation of ferrioxamines produced and further triggered biosynthesis of the unchelated siderophores, desferrioxamines. The structures of the compounds were elucidated using HRMSⁿ and by comparison with the literature. We evaluated the dynamics of siderophore production under the combined influence of chemical and biological OSMAC triggers, temporally over 3, 7, and 14 days, to discern the strain’s siderophore-mediated chemical ecology. We discuss our results based on the plausible chemical implications of S. ciscaucasicus strain GS2 in the rhizosphere.     

Rarefaction on natural compound extracts diversity among genus

The aim of our study was to investigate the intrinsic diversity of genus based on chemical composition of natural extracts of Cacalia, Dracocephalum, Jatropha, Saussurea and Senecio. Four rarefaction approaches (richness, Shannon's entropy, Simpson's diversity, and max-entropy) were implemented as an algorithm and run 10,000 times. Our results showed similar patterns of richness in natural compounds according to genus and of Simpson's diversity index while max-entropy has a similar pattern as Shannon's entropy. The analysis of both richness in active compounds and weight of most frequent extracted compound revealed that Dracocephalum genus is most suitable for propagation.     

Challenges of structure determination of compound surfaces

Attention is drawn to challenges facing the structure determination of compound surfaces of growing complexity. Besides the questions of large unit cells and disorder, and of many independent atoms in the unit cells, one must address the determination of composition, compositional disorder and simultaneously coexisting structures. Of special concern is the issue of stability of complex and compound surfaces, and the resulting concerns about experimental surface preparation and reproducibility.