Carboxylation of styrene in the N(C4H9)4Br—heptane system

The carboxylation of styrene into carboxylic acids in the N(C₄H₉)₄Br—heptane system in the presence of phosphine complexes and palladium acetate was studied. In the absence of phosphine, the Pd catalyst seems to be stabilized in solution by forming anionic complexes with NBu₄Br; the stabilization depends on the acidity of the reaction medium. The catalytic system can be used repeatedly, its activity being reduced only slightly.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2458–2461, November, 2004.     

Reaction of 2-methylene-3-oxoquinuclidine with nucleophilic reagents

The salts and quaternary derivatives of 2-methylene-3-hydroxyquinuclidine readily add nucleophilic reagents because of the high polarity and polarizability of the carbon-carbon double bond, which are due to the overall electron-acceptor effect of the positively charged nitrogen atom and the carbonyl group. The double bond is substantially deactivated in the base, and the addition of nucleophilic reagents is hindered.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1370–1376, October, 1977.     

Determination of Silicon Impurities in High-Purity Arsenic Using Atomic Emission Spectrometry with Matrix Distillation from a Tipped Electrode

A procedure for analyzing high-purity arsenic by atomic emission spectrometry (AES) was proposed that provides the preconcentration of silicon and other nonvolatile impurities in a crater of a graphite electrode using matrix distillation from 2-g sample portions as As₂O₃. The procedure is characterized by a low correction for the blank experiment. The detection limit for silicon was 4 × 10^–7 wt %.     

Synthetic analogs of natural flavolignans. V. A new synthesis of 6-halogeno-1,3-benzodioxane analogs of silandrin and hydnocarpin

6-Halogeno-1,3-benzodioxane analogs of chalcones have been synthesized by various methods. Flavanone and flavone analogs of silandrin and hydnocarpin have been obtained from them. The structures of the new flavonoids have been shown by their PMR spectra.KIEN Karakalpak Division, Academy of Sciences of the Republic of Uzbekistan, Nukus. Taras Shevchenko Kiev University, Ukraine. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 494–498, July–August, 1994.     

Determination of the position of the acyl groups and the nature of some amino alcohols in native ester alkaloids of the genusVeratrum

Conclusions 1. On the basis of literature data on the structure of theVeratrum alkaloids, a definite law for the arrangement of the acyl radicals in these ester alkaloids and an interrelationship between the melting point and the structure of the substituent in the C₇ position, and between the melting point and the types of amino alcohols upon which the ester alkaloids are based, has been found.2. The features mentioned may be used in studying the structure of theVeratrum ester alkaloids according to a scheme which we propose.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 4, pp. 440–443, 1970     

Copolymers of the C9 hydrocarbon fraction of liquid pyrolysis products with maleic anhydride and their esterification products as additives to paper pulp

The influence exerted by copolymers of the C₉ fraction of liquid pyrolysis products of petroleum raw materials with maleic anhydride and by their esterification products, added to paper pulp, on the main paper properties was examined.     

Synthesis of sterically hindered benzodioxane analogs of isoflavone and a study of their atropoisomerism

Syntheses are reported far sterically hindered 2-substituted benzodioxane analogs of isoflavone. An optically active lanthanide shift reagent (LSR) was used to show that these products exist as mixtures of atropoisomers. The difference in the chemical shifts of the enantiomeric protons in the presence of the LSR may reach 2–3 ppm with decreasing temperature. Conclusions were drawn concerning the structure of the LSR-substrate adducts and their conformations.Taras Shevchenko Kiev University, 252033 Kiev. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 902–908, July, 1996. Original article submitted March 27, 1996.     

Variable Mott-Schottky plots acquisition by potentiodynamic electrochemical impedance spectroscopy

Potentiodynamic electrochemical impedance spectroscopy provides extraction of potential-dependent space charge layer capacitance from potentiodynamic impedance spectra of non-stationary semiconductor–electrolyte interface. The new technique has been applied for acquisition of Mott-Schottky plots of cathodically treated TiO₂ anodic films. Cathodic treatment in 1 M H₂SO₄ increases donor density and flat band potential of TiO₂. Freshly doped films show hysteresis in the space charge layer capacitance in cyclic potential scans. The subsequent cycling eliminates the hysteresis but preserves the greater part of the doping effect. Presented at the 4th Baltic Conference on Electrochemistry, Greifswald, 13–16 March 2005     

New Tricyclic Amides. Synthesis,Structure, and Oxidation with Peroxyphthalic Acid

4-Azatricyclo[5.2.1.0^2,6]dec-8-ene was synthesized and brought into reactions with benzoyl, o-chlorobenzoyl, p-bromobenzoyl, p-, m-, and o-nitrobenzoyl, and bicyclo[2.2.1]hept-2-ene-endo-5,endo-6-dicarboximidoacetyl chlorides in chloroform in the presence of pyridine. The tricyclic amides thus obtained were epoxidated with peroxyphthalic acid prepared in situ by reaction of phthalic anhydride with a 35% aqueous solution of hydrogen peroxide. The structure of newly synthesized compounds was confirmed by IR and ¹H and ¹³C NMR spectroscopy and mass spectrometry. Their NMR spectra were compared with those of previously synthesized N-arylsulfonyl-4-azatricyclo[5.2.1.0^2,6]dec-8-enes on the basis of conformational composition of the corresponding p-nitrophenyl-substituted derivatives, which was determined by PM3 semi-empirical quantum-chemical calculations.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 6, 2005, pp. 837–845.Original Russian Text Copyright © 2005 by L. Kas’yan, Okovityi, Tarabara, A. Kas’yan, Bondarenko.     

Synthesis and photochromic properties of indolinospirochromenes with electron-donor substituents in the indoline part of the molecule

1,3,3-Trimethylspiro(indoline-2,2'-[2H]chromenes) with CH₃ and CH₃O groups in the 4–7 positions and NO₂ and CH₃O groups in the 6 and 8 positions were obtained by the reaction of 4,6-, 4,7-, 5,6-, and 6,7-dimethoxy- and 4-methyl-7-methoxy-2-methyleneindolines and 1,3,3,4,5,6,7-heptamethyl-2-methyleneindoline with 3- and 5-nitrosalicylaldehydes and their derivatives. Most of the compounds have photochromic properties. The introduction of electron-donor groups into the indoline fragment of the spirochromene molecules changes the rate of the dark reaction within the limits of one order of magnitude and has a small effect on the position of the long-wave absorption band of the photomerocyanine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1220–1224, September, 1982.