Carbenes,related intermediates,and small-sized cycles: contribution from Professor Nefedov’s laboratory

The review summarizes some of the most prominent results obtained in the laboratory headed by Academician Oleg M. Nefedov at the N. D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences in the field of chemistry of carbenes, their heavy analogs, and related intermediates, as well as small-sized cycles. Those include elaboration of safe methodology of cyclopropanation using diazomethane, development and extension of synthetic applications of diazoesters and other diazo compounds in the preparation of valuable chemical products, design of functionalized alkynylcyclopropanes on the basis of alkynylcarbene reactions, creation of versatile synthetic approaches to preparation of various practically useful fluoroorganic compounds on the basis of reactions of fluorocarbenes, development of synthetic applications of heavy carbene analogs and synthesis of small-sized heterocycles containing silicon and germanium atoms, analysis of mechanisms of some important reactions of carbenes, their analogs and related intermediates on the basis of physicochemical studies, direct spectroscopic studies of various labile intermediates of chemical reactions.     

等物质的量定律及其应用

本文指出了滴定计算中等物质的量规则的缺陷,并提出了等物质的量定律,将这个反映化学反应客观规律的定律定义为:在氧化还原反应体系中氧化剂与还原剂得与失电子的物质的量相等;在酸碱反应体系中酸与碱得与失质子的物质的量相等;在沉淀反应中阳离子与阴离子所具有电荷的物质的量相等;在络合滴定中金属离子与氨羧络合剂的物质的量相等。等物质的量定律可用下式表达:(i=k)∑(i=1)△n(1/z_Ai)Ai=(i=P)∑(i=1)△n(1/z_Bi)Bi。这个定律及其表达式能使复杂的滴定分析计算简单化、规范化。     

Stoichiography and present-day analytical chemistry of solid inorganic substances and materials

The article covers factors that determine fundamental difficulties of chemical phase analysis of a mixture of solid phases of inorganic compounds. Stoichiographic principles and methods, novel for analytical chemistry and leading to the efficient solution of the problems of phase analysis, are discussed. Conditions of the selective separation of mixtures of multiphase multielement solid compounds and principles of the new method, fan-like separation, ensuring the extraction of individual phases from unseparated mixtures, are considered. An idea of a complex method of solving analytical problems by stoichiography methods in proposed. The problem of the multiplicity of objects of analysis is discussed and general principles of the efficient solution of problems of the detection and identification of components of complex mixtures of unknown chemical composition are considered.     

Application of nonspecific biosensors methodology for right choice of diagnostic criteria for food allergy and intolerance on the basis of specific human IGG determination

Under consideration is the application of a methodology of nonspecific biomarkers to the interpretation of the titers of specific immunoglobulins of type IgG for the purpose of accurate determination of a threshold between normal and abnormal values. Proposed is a mathematical model of assessment of a phase status of a biological entity based on the ranking of a series of concentrations of specific immunoglobulins of type IgG.     

Computer simulation of the structure formation and disruption processes in the solid-liquid disperse systems

Results of the computer simulation of solid-liquid disperse systems are reported. Main regularities of the formation and disruption of the internal structure of such systems are demonstrated under static and dynamic conditions (including the combination of shear and orthogonal vibrations). The effect of the character of the interaction of dispersed phase particles, as well as of a number of parameters concerning the type and intensity of external actions on the behavior of disperse systems is shown. The possibility of the regulation of the character of microstructure and rheological properties of disperse systems by the combination of shearing and orthogonal vibrations is illustrated.     

Die Wasserstoffbrückenbildung als primärer Elementarvorgang bei der Ionisation schwacher Säuren und bei Säure-Basen-Katalysen in wäßriger Lösung

The mechanism of the ionisation of weak acids was elucidated according to the interpretation of the acid—base-catalysis of the mutarotation of α-glucose by the author. The primary elementary reaction of the ionisation of weak acids is the exothermic formation of the hydrogen bridge of the acid with the polar solvent. The secondary reaction is the endothermic total transfer of the proton to the solvent. The thermodynamic values of both elementary reactions were determined for the ionisation of different weak acids in aqueous solution and in this way a contribution was made to the thermodynamics of intermediate reactions which was propagated by the autorh. The formation of hydrogen bridge at the acid—base-catalysis of the mutarotation of α-glucose is discussed from the point of view of the mechanism of ionisation of weak acids. Furthermore the limits of the validity of theBrönsted equation for the acid—base-catalysis of the mutarotation of α-glucose were demonstrated.     

Interaction of carbamazepine and promethazine in rabbits

The interaction of carbamazepine and promethazine in rabbits has been investigated. The influence of this interaction on the processes of biotransformation in the liver was revealed. The drugs were administered as single oral doses (100 mg of each drug) as well as simultaneously with an interval of 15 min. The sequence of administration of the drugs was varied. The influence of promethazine on the pharmacokinetics of carbamazepine is expressed by: (a) strong suppression of carbamazepine's level in plasma and appearance of multiple peaks of carbamazepine; (b) suppression of biotransformation of carbamazepine into carbamazepine-10,11-epoxide at the initial stages and its increase in the intermediate stages. These data are explained by the active capture of carbamazepine by liver at its primary transferal through the liver and sufficient presystem elimination of carbamazepine in the presence of promethazine. The character of kinetic curves of promethazine varies substantially under the influence of carbamazepine. However, this change is not as strong as in case of carbamazepine. The concentration of promethazine in plasma varies slightly and multiple peaks are not observed. The rate of terminal elimination of promethazine varies and abrupt prolonged segments of elimination appear at the initial and terminal stages of the process in return. These data perhaps indicate the induction of biotransformation of promethazine in the presence of carbamazepine-an inductor of microsomal liver enzymes. The changes of kinetics of promethazine and carbamazepine by simultaneous administration as compared with their administration separately, as well as a comparative consideration of pharmacokinetics of promethazine and carbamazepine by simultaneous administration show the existence of competition in the elimination between these drugs and the periodic saturation of liver for their biotransformation.     

扭辫分析法对糠醛聚合反应机理的研究

中村仪郎等对经酸催化而得的糠醛树脂通过红外和紫外光谱进行了结构分析。     

Photosensitized Damage Inflicted on Plasma Membranes of Live Cells by An Extracellular Generator of Singlet Oxygen—A Linear Dependence of A Lethal Dose on Light Intensity

We describe a study of the influence of a dose rate, i.e. light intensity or photon flux, on the efficiency of induction of a loss of integrity of plasma membranes of live cells in culture. The influence of a photon flux on the size of the light dose, which was capable of causing lethal effects, was measured in an experimental system where singlet oxygen was generated exclusively outside of live cells by ruthenium(II) phenantroline complex. Instantaneous, sensitive detection of a loss of integrity of a plasma membrane was achieved by fluorescence confocal imaging of the entry of this complex into a cell interior. We demonstrate that the size of the lethal dose of light is directly proportional to the intensity of the exciting light. Thus, the probability of a photon of the exciting light inflicting photosensitized damage on plasma membranes diminishes with increasing density of the incident photons.     

Selectivity of the stationary phase in gas-liquid chromatography

The use of molar refractions is insufficient to describe the retention volumes and thermodynamic functions of solutions in nonpolar stationary phases. The heats of dissolution of monofunctional derivatives of the alkanes are proportional to the polarizability and inversely proportional to the sixth power of the van der Waals' radius of the interacting particles. The heat of dissolution of substances being analyzed, with the same number of carbon atoms, in aromatic solvents depends on the conditions of contact between the molecules of the substances being analyzed and the benzene rings of the solvent. The order of the heats of dissolution of substances being analyzed in different nonpolar solvents does not remain the same, indicating that the theory of regular solutions cannot be applied to these systems. To determine the order of the heats of dissolution of isomers in nonpolar stationary phases it is necessary to take account of the electron density distribution in the molecules of the reacting substances and the probability of molecular arrangement for the most favorable interaction.     

Water-soluble polyelectrolyte complexes of pyridine-containing polyphenylene dendrimers

The sizes of soluble polyelectrolyte complexes formed through mixing of solutions of dimethyl sulfate-alkylated rigid pyridine-containing polyphenylene dendrimers of various generations with the solution of sodium polystyrenesulfonate are measured with the use of dynamic light scattering. Effects of the length of the polyanion chain of the dendrimer, the generation number of the dendrimer, and the charge ratio of polymer components on the sizes of the complexes are examined. The results of this study are in agreement with the theoretical analysis of interaction between the charged dendrimer and the polyelectrolyte of the opposite charge sign and suggest the spontaneous formation of nanosized particles of water-soluble complexes.     

Lipids of the oils of the fruit and leaves ofHoppopha? rhamnoides

The analysis of some lipids of four forms of the common sea buckthorn has shown that they all differ with respect to the composition of the fatty acids of the triacylglycerols of the leaves. One of the forms is characterized by an infringement of the specificity of the composition of the fatty acids in positions 2 of the triacylglycerols of the oils of the seeds and the leaves.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. V. L. Komarov Institute of Botany, Academy of Sciences of the Azerbaidzhan SSR, Baku. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 710–715, November–December, 1981.     

Kinetic Regularities Governing the Reaction of Electrodeposition of Iron from Solutions of Citrate Complexes of Iron(III)

The kinetics of a multistep reaction of electrodeposition of iron out of aqueous citrate-containing solutions of trivalent iron is investigated. It is shown that concentrations of major solution components affect the partial current density of discharge of ions of divalent iron. It is established that the deposition of metallic iron occurs as a result of discharge of intermediates, which are hydroxy complexes of divalent iron. Kinetic parameters and mechanism of the reaction of discharge of complexes [FeOH]⁺ to a metallic state are determined. It is mentioned that the formation of poorly soluble hydroxy compounds of trivalent iron in a near-electrode layer leads to a decrease in the iron deposition current.     

Virtual screening of organic molecule databases. Design of focused libraries of potential ligands of NMDA and AMPA receptors

A system of virtual screening of organic molecule databases is designed, which permits preprocessing of databases, molecular docking to a three-dimensional model of receptor, and post-processing of the results obtained. Using this screening system, it is possible to reproduce positions of the known ligands in the glutamate sites of the NMDA and AMPA receptors and in the glycine site of the NMDA receptor, to substantially enrich the database with potentially active compounds, and to distinguish between the agonistic and antagonistic character of the action of these compounds in the case of docking to the open and closed forms of the binding sites. Based on the results of screening of a database of low-molecular-weight organic compounds (total of 135,000 structures) using models of the open and closed forms of the glutamate and glycine sites of the NMDA receptor and of the glutamate site of the AMPA receptor, focused libraries of potential agonists and antagonists of these sites were designed.     

能量分辨质谱鉴别卤代4(3H)-喹唑啉酮异构体

应用能量分辨质谱分别研究了氯代4(3H)-喹唑啉酮异构体和氟代4(3H)-喹唑啉酮异构体的单体及异构体单体的混合物的能量质谱裂分曲线。结果表明,在碰撞能量0.8～1.5V的变化范围内,氯代4(3H)-喹唑啉酮异构体单体及混合物的碎片离子m/z 145与m/z 125的离子强度比值相对于碰撞能量的变化曲线,即裂分曲线与氯官能团的取代位置密切相关,而氟代4(3H)-喹唑啉酮异构体单体及混合物的碎片离子m/z 136与m/z 108的离子强度比值的裂分曲线则与氟官能团的取代位置密切相关,差异显著;据此可以成功鉴别卤代4(3H)-喹唑啉酮异构体的单体及混合物的构成。     

The application of microfine ionites for the improvement of the efficiency of sorption processes in drug production (Review)

Results of the application of microfine ionites of different classes for sorption methods in the production of versatile drugs are systemized. Kinetic and dynamic parameters of sorption isolation and chemical purification of drugs with participation of ion-exchanger of small graining are discussed; essential advantages of their application allowing intensification of ion-exchange technological processes of drugs production are determined. The review can be useful at elaboration of new sorption methods used for the production of the wide assortment of drugs and, first of all, antibiotics, enzymes, and vitamins.     

Thermal decomposition of kerogens: Mechanism and analytical application

Specific features of the chemical structures of organic matter (Lerogen) in oil shales caused by the nature of the starting materials for the formation of shales and the routes of their subsequent alteration are reflected in the composition of shale semicoking (retorting) oil. In order to establish the analytical possibilities of the thermal decomposition method in elucidating the kerogen structure and to obtain more data on the mechanism of the pyrolysis of kerogens, the effect of a series of factors (rate of heating, pressure, presence of carrier gases, water and mineral matter of shale, treatment with reagents) on the yield and composition of the pyrolysis products of oil shales was investigated.The yield of shale oil and the phenol content in the latter increase when semicoking is performed in a stream of hydrogen at atmospheric pressure. In shale pyrolysis in the presence of water under pressure, the yield of oil and, in particular, water-soluble organic compounds also increase, as well as the content of neutral heteroatomic compounds in oil. With increasing content of mineral substances in shale, the yield of the semicoking oil (kerogen basis) and the content of polar compounds in it diminish owing to an increasing influence of oil adsorption on the mineral matter and its additional decomposition as a result.In the initial stage of thermal decomposition, both longer aliphatic substituents and side-chains of iso-structures split off and alkenes with a double bond in the middle of the chain (probably the products of elimination and dehydration of the aliphatic substituents with a hydroxyl group) are formed. The formation of n-1-alkenes, particularly those of even carbon number, which originate from the side-chains of odd carbon number by the cleavage of carbon–carbon bonds in the β-position to the cyclic nucleus of kerogen, becomes more pronounced in the final stage of pyrolysis when, owing to significant aromatization of the cyclic part of kerogen, the selectivity of the β-cleavage increases.     

Estimation of limits of detection and determination in X-ray fluorescence analysis by the dependence of the relative standard deviation on analyte concentration

An experimental dependence of the relative standard deviation on analyte concentration of hyperbolic type, characterizing the precision of quantitative chemical analysis, was used to estimate the limits of detection and determination in the X-ray fluorescence analysis. A method is proposed for the determination of their values using the approximation of the experimental dependence of the relative standard deviation on the analyte concentration by a power function. The choice of the values of the relative standard deviation, being criteria for the estimation of these limits, is substantiated. A concept of the limits of detection and determination of an analytical procedure is formulated, according to which the limit of detection of an analytical procedure is an objective value depending only on the precision of determinations, and the limit of determination of an analytical procedure is a subjective value depending not only on the precision of determinations but also on the requirements to their limiting (admissible) accuracy. The limits of detection and determinations of an analytical procedure found by this approach completely characterize the possibilities of an analytical procedure in determining low concentrations of analytes. The proposed approach can be used for the estimation of the limits of detection and determination of analytical procedures and in other methods of chemical analysis with the hyperbolic dependence of the relative standard deviation on the analyte concentration.     

碳原子价轨道电负性对化学键性能的影响

研究了同一类型化学键X―C的键能、键长和H―C键的酸性等性能与碳原子价轨道电负性的定量关系。结果表明,X―C键能随碳原子价轨道电负性增加而线性增大;H―C与C―C键的键长随碳原子价轨道电负性增加而线性减小;H―C的酸性随碳原子价轨道电负性增加而线性增大。因而,对结构类似的有机化合物,可以采用碳原子价轨道电负性对实验测定的化学键性能作图,判断其测定结果正确与否。     

Heterocyclic nitro compounds XIX. Kinetics of the methylation of 3(5)-nitro-1,2,4-triazoles with dimethyl sulfate

The effect of a substituent in the triazole ring and of the composition of the solvent on the reaction rate was established as a result of a study of the kinetics of methylation of sodium salts of 3(5)-nitro-1,2,4-triazoles in water and water-dioxane mixtures. The relationships found are due to the different degree of dissociation of intimate ion pairs of anions of nitrotriazoles with sodium and the specific character of the solvation of the anions by water.