Allylboranes: reductive mono andtrans-diallylation of aromatic nitrogen-containing heterocyclic compounds

Reductive-mono- and stereoselective trans-,-diallylation of aromatic nitrogencontaining heterocycles by allylic boron derivatives have been discovered. A method for thetrans-to-cis isomerization oftrans-2,5-diallylpyrrolidines andtrans-2,6-diallyl-1,2,5,6-tetrahy-dropyridines by heating with allylboranes has been developed. The above reactions unite the chemistry of nitrogen-containing heterocycles and the chemistry of organoboron compounds on a new level.This review is based on a report presented at the conference INEOS-94: Modern problems of organometallic chemistry (May 21–27, 1994, Moscow).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1203–1216, July, 1995.The author is sincerely grateful to his colleagues E. A. Shagova, S. V. Evchenko, L. I. Lavrinovich, A. Yu. Zykov, E. V. Klimkina, and A. V. Ignatenko for their active participation in this work, as well as to M. E. Gurskii, I. D. Gridnev, and A. V. Geiderikh for useful advice and critical notes.This study was financially supported in part by the Russian Foundation for Basic Research (Grant No. 93-03-18193) and the International Science Foundation (Grant M3Y 000).     

Phosphorescence of aromatic molecules in complexes with crystalline β-cyclodextrin at room temperature

The rate constants for the quenching by oxygen of triplet states of aromatic molecules (naphthalenes-d₈ and-h₈, phenanthrene) forming inclusion complexes with crystalline β-cyclodextrin in water at 290 K are equal to 900–1300 L mol⁻¹s⁻¹. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1450–1453, August, 1997.     

Determination of column selectivity toward polycyclic aromatic hydrocarbons

An empirical test is described for the evaluation of column selectivity in reversed-phase liquid chromatography. Using a test mixture of three polycyclic aromatic hydrocarbons (PAH), overall column selectivity toward PAH was assessed for over 20 different commercial C₁₈ columns. Retention behavior was correlated to phase type (i.e., monomeric and polymeric surface modification chemistry) for custom synthesized phases. A classification scheme is proposed in which commercial C₁₈ columns are grouped into three classes based on retention behavior: monomeric-like, polymeric-like, and intermediate phase selectivity toward PAH. Correlation of retention behavior of the test mixture with the separation of PAH mixtures and with more general column properties (e.g., phase thickness) is discussed.     

Novel organometallic aromatic polyester based on ferrocene

<正>A novel polyester containing ferrocenyl was prepared by low-temperature interface polycondensation of 1,1'-ferrocenedicarboxylic acid chloride with 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one(DHPZ),which is a twisted non-coplanar heterocyclic bisphenol-like monomer.The newly generated polymer was evaluated based on characterization of its solubility,viscosity measurements,elemental analysis,FTIR spectroscopy,differential scanning calorimetric and thermogravimetric studies.     

The impact of vertical π-extension on redox mechanisms of aromatic diimide dyes

The impact of vertical π-extension on redox mechanisms of aromatic diimides in the organic lithium-ion batteries have been carefully studied by a combined experiment and theoretical analyses.     

Catalytic reduction of aromatic polynitro compounds

The liquid-phase catalytic hydrogenation of 3,5-dinitrophenyl phenyl ether to give 3,5-diaminophenyl phenyl ether in the presence of Group VIII metals as catalysts has been investigated. The main kinetic characteristics of the process have been established. The reduction occursvia the formation of 5-amino-3-nitrophenyl phenyl ether. In terms of their activity, the catalysts studied can be arranged in the following sequence: 1% Pd/Sibunit> 2 % Pd/C > Lindlare Pd > 5% Ru/Sibunit > Raney Ni. The selectivity of the process with respect to intermediate 5-amino-3-nitrophenyl phenyl ether depends on the relative adsorption abilities of mono- and dinitro compounds. A promoting effect of water during hydrogenation of 3,5-dinitrophenyl phenyl ether in isopropanol or 1,4-dioxane has been noted. Catalytic synthesis of 3,5-diaminophenyl phenyl ether has been carried out for the first time.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1716–1719, September, 1995.     

Transition metal free large-scale synthesis of aromatic vinyl chlorides from aromatic vinyl carboxylic acids using bleach

While continuing our research on Hunsdiecker reaction, we came across an interesting application of bleach, sodium hypochlorite (NaOCl) for decarboxylative chlorination reaction. The reaction is easily scaled up to 10?mmol. The reaction has good tolerance towards wide variety of functional groups. The reaction has mild conditions and gave relatively high chemical yield of the desired product.     

SFC in analysis of aromatic plants

Capillary SFC was applied to the analysis of Some plant volatile oils. The results were compared with those obtained by capillary GC. For thyme oil, SFC without derivatization gave about the same percentage composition of the main compounds as CGC with silylation, thus eliminating one working step. For a complex mixture of peppermint oil or basil oil, SFC seems to give more reliable quantification than CGC, especially for oxygenated compounds. However, the separation efficiency of CGC for monoterpene hydrocarbons was, as expected, much better than that of SFC.     

Novel synthesis of aromatic polysulfides from S,S′-bis(trimethylsilyl)-substituted aromatic dithiols and activated aromatic dihalides

A new method for the synthesis of aromatic polysulfides has been developed by the polycondensation of S,S′-bis(trimethylsilyl)-substituted aromatic dithiols with activated aromatic dihalides. The solution polycondensation of three S-silylated aromatic dithiols with bis(4-chloro-3-nitrophenyl) sulfone afforded readily aromatic polysulfides having inherent viscosities of 0.7 dL/g, and the polymerization with bis(4-fluorophenyl) sulfone gave the polymers with viscosity values of 0.3 dL/g. The silylation method was compared advantageously with a conventional route using parent dithiols and activated aromatic dihalides.     

Silver-mediated aminophosphinoylation of propargyl alcohols with aromatic amines and H-phosphine oxides leading to α-aminophosphine oxides

A new silver mediated aminophosphinoylation of propargyl alcohols with aromatic amines and Hphosphine oxides for the construction of a-aminophosphine oxides has been developed.The C-N and C-P bond could be efficiently formed in one pot operation via sequential C-C and C-O bond cleavage of propargylic alcohols.This present methodology,which not only provides a simple and alternative strategy for the synthesis of α-aminophosphine oxides,but also opens a new window for the cleavage reactions of propargyl alcohols via dealkynalation coupling.     

Separation of isomers of nitro-polycyclic aromatic hydrocarbons

Since positional isomers of several nitro-polycyclic aromatic hydrocarbons (nitro-PAH) contain widely different mutagenic properties, methods for separating the isomers were investigated. High performance liquid chromatography with dichloromethane in hexane on silica gave the best resolution for the majority of the compounds. A few groups of isomers were better resolved with other modifiers or with reversed phases. Of the reversed phase systems, methanol-water gave better resolution than acetonitrile-water. With dichloromethane/hexane on silica, the retention was found to depend on the presence of a bay nitro group (first), the number of H atoms peri to the nitro group (second), and the length/breadth ratio of the molecule (third). Front electron density calculations were combined with the structure-retention relations in making tentative structure assignments of minor isomers of nitro-PAH.     

Enrichment of polycyclic aromatic hydrocarbons in seawater with magnesium oxide microspheres as a solid-phase extraction sorbent

The enrichment of polycyclic aromatic hydrocarbons (PAHs) in water samples with magnesium oxide (MgO) microspheres was evaluated, and four 3-5-ring PAHs were used as probes to validate the adsorption capacity of the material. Factors affecting the recovery of PAHs were investigated in detail, including the type and concentration of organic modifiers, elution solvents, particle size of the adsorbent, volume and flow rate of the samples, and the lifetime of MgO cartridges. The recoveries of four PAHs extracted from 20 mL of seawater spiked with standard PAHs ranged from 85.8% to 102.0% under the optimised conditions. The limits of detection varied from 1.83 ng L⁻¹ to 16.03 ng L⁻¹, indicating that the analytical method was highly sensitive. Additionally, the proposed method was successfully used to enrich PAHs in seawater. Compared to conventional methods, the proposed method consumed less organic modifier (5% acetone), and cheaper sorbents with comparable extraction efficiency were employed.     

Peroxydisulphate oxidations VII. Identification of aromatic amines and phenols by thin-layer chromatography

Ohne Zusammenfassung

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On a specific detection of morphine by thin-layer chromatography

     

Alkanoylation of quinazoline by nucleophilic aromatic substitution: Combined experimental and computational study

A combined experimental and computational study on the key intermediates of NHC-catalyzed acylation reaction, Breslow intermediates (BIs), has been conducted in order to achieve a direct nucleophilic alkanoylation of N-heterocycles. Various BI precursors are alternatively prepared and used in the reaction with 4-chloroquinazoline. The present study reveals that the intermediates having benzimidazole moiety serve as acylating agents for the introduction of straight-chain alkanoyl groups. Natural bond orbital analysis indicates that the reactivity of intermediates partly correlates to the occupancy of the π_C-C bonds of the hydroxyl enamine moieties. The putative rate-determining step of the acylation reaction has been theoretically investigated. Several new 4-alkanoylquinazolines are synthesized using the BI precursors.     

Mapping the phase diagram of an aromatic polyamide blend using infrared spectroscopy

The results of an infrared study of poly (meta-phenylene adipamide)-poly (ethylene oxide) blends are reported. This is the first time, to the authors' knowledge, that infrared spectroscopy has been used to experimentally map the phase diagram of a polymer blend. The results are compared with theoretical phase diagrams calculated from a recently described association model.     

Reaction of 3,3-dichloropentane-2,4-dione with aromatic aldehydes under the conditions of Darzens reaction

3,3-Dichloropentane-2,4-dione reacts with aromatic aldehydes under the conditions of Darzens reaction to give 4-acetoxy-4-aryl-3,3-dichlorobutan-2-ones, the products of insertion into the -C-C bond. The reaction of ethyl dichloroacetylacetate with benzaldehyde yields a derivative of tricyclo[5.1.0.0^3,5]octane, rather than 2,6-bis(1-chlorobenzylidene)cyclohexane-1,4-dione, as the by-product.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1294–1298, July, 1995.