Structure of the products of the photoreaction of osthole

The results are given of a study of the photoreaction of osthole in chloroform and acetophenone. It has been shown that when it is irradiated in the latter solvent the cyclization characteristic for coumarins takes place at the double bonds both in the 3,4- position of the coumarin ring and in the side chain, leading to the formation of cyclobutane structures.Leningrad Sanitary-Hygienic Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 165–168, March–April, 1980.     

缺Zn症患儿微量元素水平的样本特征分析及其临床补Zn治疗的评价

测定了150例缺Zn症患儿及健康儿发样中的Zn、Ca、Mg及Fe四元素水平．采用主成分分析法．将高维空间中的样本点映射到低维空间中来观察，研究其样本特征，评价临床补Zn治疗措施．结果瑶明：缺Zn症患儿体内缺Zn是病理的主要方面，但往往同时伴有其它微量元素水平偏低现象，临床缺Zn症状的表现可能为多种元素综合效应的反映．因此临床治疗不能单纯考虑朴Zn，还应结合患儿体内其他元素水平的具体情况，考虑其他元素的补给．治疗才能奏效显著．     

Thermodynamic parameters of solvation of nonelectrolytes in aqueous solutions of amides of carboxylic acids

Interaction and reorganization contributions to solvation enthalpies of nonelectrolytes in aqueous solutions of amides of carboxylic acids with different degree of N-substitution and N-methylpyrrolidone are calculated. The data are discussed using structurally thermodynamic characteristics of water-amide systems obtained by us previously. It is found that the type of concentration dependence of the solvation enthalpy of nonelectrolytes in all solutions investigated is determined by the type of reorganization component. It is shown that the highest solvation exothermicity of nonelectrolytes in water is due to the lowest value of the reorganization contribution in spite of that nonelectrolytes interact weaker with water than with non aqueous components.     

Investigation of the products of the ozonolysis of larixol

On the ozonization of larixol in methanol followed by treatment with ammonium chloride, the main reaction products were 15,16,20-trisnorlabd-6-ene-8,13-dione and 6-hydroxy-8,13;8,14-diepoxy-15,20-bisnorlabd-14-one. When ozonization was performed in methanol in the presence of dimethyl sulfide or in methylene chloride in the presence of pyridine, 6,14-dihydroxy-8,13;8,14-diepoxy-15,20-bisnorlabdane and 6-hydroxy-14,50,20-trisnorlabd-8,13-dione predominated in the reaction products.Institute of Chemistry of the MSSR Academy of Sciences, Kishinev, and Institute of Organic Chemistry of the Bashkir Branch of the USSR Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 577–584, September–October, 1986.     

Preparation of composite membranes by means of plasma polymerization of tiophene

The structure and the charge transport properties of poly(ethylene terephthalate) track membranes modified in a thiophene plasma were studied. It was found that polymer deposition on the surface of a track membrane via the plasma polymerization of thiophene results in composite membranes that, in the case of the formation of a semipermeable layer, exhibit conductivity asymmetry—rectifying effect—in electrolyte solutions. It was shown that chemical doping with iodine or photo-oxidation of the polymer layer produced in plasma leads to alteration in the electrochemical properties of plasma-modified membranes.     

Effect of composition of coordination sphere on value of constant of additional hyperfine structure of EPR spectra

Conclusions Replacing the oxygen atoms by sulfur atoms in the coordination sphere of nitrogen-containing copper complexes leads to a substantial increase in the constant of the additional hyperfine structure from the nitrogen atoms, and consequently also to an increase in the degree of covalency of the Cu-N bonds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 704–706, March, 1974.The authors thank V. I. Nefedov for taking the x-ray electronic spectra of compounds (I) and (II).     

Investigation of the products of the ozonolysis of larixol

On the ozonization of larixol in methanol followed by treatment with ammonium chloride, the main reaction products were 15,16,20-trisnorlabd-6-ene-8,13-dione and 6-hydroxy-8,13;8,14-diepoxy-15,20-bisnorlabd-14-one. When ozonization was performed in methanol in the presence of dimethyl sulfide or in methylene chloride in the presence of pyridine, 6,14-dihydroxy-8,13;8,14-diepoxy-15,20-bisnorlabdane and 6-hydroxy-14,50,20-trisnorlabd-8,13-dione predominated in the reaction products.     

Synthesis of a Pair of Derivatives of N-Methylpyrrole Polyamide

A pair of derivatives of tetrameric N-methylpyrrole polyamide were synthesized in order to develop a new method for the study of interaction of the polyamide derivatives with DNA. Indole acetic acid and nicotinic acid were introduced to the polyamide in the synthesized compound, which showed an expected red shift in the UV spectrum. These compounds may function as a potential tool in the detection of the polyamide binding to DNA.     

Composition of lipids of the grain of opaque-2 maize

It has been established that the change in the composition of the total lipids and the fall in the fatty acid content depend on the initial maize genotype. A decrease in the amount of unsaponifiable substances in the grain of mutants is accompanied by qualitative changes in the composition regardless of the nature of the genotype.Scientific-Research Institute of Biology Dnepropetrovsk State university. Translated from Khimiya Prirodnykh Soedinenii. No. 3. pp. 360–363. May–June, 1988.     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

Elucidation of the Structure of Products of Triphenylphosphine Electrooxidation in the Presence of Camphene

The structure of the products of anodic oxidation of triphenylphosphine in the presence of camphene carried out in acetonitrile with sodium perchlorate as supporting electrolyte has been studied. The major product, triphenylphosphine oxide, has been isolated from the solution in the form of cocrystals of free triphenylphosphine oxide and its complex with sodium perchlorate. The molecular structure of the cocrystals has been studied by X-ray diffraction analysis. Triphenylcamphenylphosphonium perchlorate, bornylacetamide, and a terpene compound with triphenylphosphonium and acetamide substituents in the cycle have been detected by NMR ¹³C as the electrolysis side products.

     

Determination of the extent of acid hydrolysis of N-methylpyrrolidone

The extent of the hydrolysis of N-methylpyrrolidone in dilute hydrochloric acid can readily be determined by titrating an aliquot of the reaction mixture in absolute ethanol with tetrabutylammonium hydroxide. A separate equivalence point is observed in the titration curve for each of the three types of ionisable hydrogens involved.     

Investigation of the lability of the conformations of some alkaloids of the quinolizidine series

Summary The IR and NMR spectra of lupinine, epilupinine, and a series of other alkaloids of the quinolizidine series have been studied.It has been shown that the inhibition of the inversion processes in the molecules of the alkaloids in the solid phase is revealed in a change in the nature of the absorption in the 500–1200 cm^2–1 region.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 49–54, January, 1971.     

Improvement of the efficiency of electrochemical refining of cobalt

To improve the purity of cobalt produced by electrochemical refining, the optimal electrolyte composition and electrolysis mode were determined and a method for diminishing the electrochemical activity of impurity metals in anodic dissolution of the raw metal and a system for deep purification of the electrolyte solution to remove impurities were developed. Cathode deposits with a conditional cobalt content exceeding 99.999 wt %, found in an analysis for the 11 main impurities, were obtained by using the above results in refining of K1A cobalt (≥99.30 wt % Co) in an electrolyzer of distinctive design.     

Effect of Pore Structure of Al-Co-Mo Catalyst on the Rate of Various Pathways of Hydrofining of Oil Residues

Evolution in the activity and texture of the Al-Co-Mo catalyst in hydrofining of black oil is studied. The catalyst efficiency in desulfurization, deasphalting, and demineralization of black oil is estimated as dependent on the catalyst pore structure and process conditions.     

Mechanism of self-assembly of rigid-chain macromolecules of cellulose ethers in solutions

With the aid of the turbidity-spectrum method, the cloud-point method, X-ray analysis, and polarization microscopy and the use of a polarization-photoelectric apparatus, the sizes of supramolecular particles are determined and the liquid-crystalline phase transitions and the structure of cellulose ether solutions are studied in a wide composition range. As the concentration of the polymer in solution increases, the sizes of light-scattering particles tend to increase from several nanometers to several thousand nanometers. This effect is the most pronounced during formation of the liquid-crystalline phase. The “packet” mechanism of self-assembly of macromolecules is advanced. For cyanoethyl cellulose macromolecules, the coilhelix transition is observed with an increase in the concentration of the polymer in solution. For the cyanoethyl cellulose-dimethylacetamide system, the method for calculating the amount of macromolecules in supramolecular particles in both isotropic and anisotropic regions is suggested.     

Laboratory of Spectrochemical Analysis of the Research Institute of Physics of St. Petersburg State University

The events which initiated the organization of the Laboratory of Spectrochemical Analysis and the Division of Optics of the Department of Physics of Leningrad State University in 1948 are set forth. The steps in the growth of the laboratory and the transformations in the main fields of scientific research are considered. The important role of the laboratory staff at all steps of its work is noted both in the development of methods of spectrochemical analysis and their application as well as in training students and highly skilled personnel in analytical spectroscopy. The researchers of the laboratory who made a great contribution to analytical spectroscopy are listed.     

溶剂化效应对6-亚甲基环戊二烯酮与HCN的反应机理影响的理论研究

在B3LYP/6-311+G**计算水平上, 采用导体极化连续模型研究了溶剂化效应对6-亚甲基环戊二烯酮与HCN反应生成主要产物b类酸的反应机理的影响. 计算结果表明, 在溶剂中的反应机理与在气相中的反应机理一致. 溶剂化效应使反应路径中各驻点的自由能降低, 稳定化了各物质. 溶液中的活化自由能与气相相比也有所降低, 反应更容易发生, 其中CC进攻方式的活化自由能降低得更多.     

Enthalpies of mixing of fused salts

Starting from our previously proposed model of fused alkali metal halides, we discuss the processes involved in the mixing of fused alkali metal halides and dissolution (mixing) of TiCl₄(g)[ZrCl₄(liq)] in fused alkali metal halides and their mixtures. The resulting quantities are compared with the experimental. They vary with changes in the radius of the salt-solvent cation in the same direction as the experimental values. The dissolution of KCl_z in mixtures of fused alkali metal halides was considered from the point of view of the energy nonuniformity of the Me₁ ⁺ and Me₂ ⁺ cations.It was shown that the experimentally observed increase in the enthalpy of mixing with increasing radius of the cation of the salt-solvent is caused not so much by a change in the bond energies of the KCl _n ^z–n complexes in various media, as by a change in the bond energies of complex MeCl ₄ ^3– anions of the solvent.     

Monooxygenase activity of metalloporphyrins and mechanism of activation of molecular oxygen

Reaction rate constants have been measured for the oxidation of cholesterol by atmospheric oxygen in the presence of tetra-meso-substituted metalloporphyrins [MP] (M = Ni, Cr, Mn, Fe, Co). The results have been interpreted by the use of data on the structure of metal complexes and reaction mechanisms. It has been established that the reaction proceeds at a high rate when the oxygen in the composition of the intermediate complex [MO₂P] is in the singlet spin state. The singlet state of O₂ is occupied in the case in wich the metal ion in the porphyrin complex is in a high-spin state. The spin state and related catalytic activity of the metalloporphyrin is regulated by meso-substituents in the porphine ring. The influence of meso-substituents is predicted theoretically within the framework of a generalized orienting effect, the presence of which is supported by an analysis of ¹³C NMR data for meso-substituted metalloporphyrins.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 4, pp. 428–435, July–August 1987.