Russian Chemical Bulletin最新文献

The cyclocondensation of 2-aminobenzamide with 3,4-dimethoxypyridine-2-carbaldehyde affords a mixture of 2-(3,4-dimethoxypyridin-2-yl)-2,3-dihydroquinazolin-4(1H)-one and its open-chain tautomer. The dehydrogenation of these compounds with benzoquinones (DDQ, chloranil) as oxidants, giving 2-(pyridin-2-yl)quinazolin-4(3H)-ones, is accompanied by the demethylation of the methoxy group at the C(3) position of the 2-pyridyl moiety. When using 2-methoxy- or 2,3,4-trimethoxybenzaldehydes as deaza analogs of this aldehyde, the demethylation does not occur in the last step regardless of the nature of the oxidant.

The review is concerned with recent advances in the synthesis of homo- and heteroradical blocks for multi-spin systems, new functionalized verdazyls as components of organic batteries and spintronic devices, verdazyl-containing monomers and light-emitting radicals, as well as contrast agents and photosensitizers for medical applications.

The review is focused on the modern trends in the synthesis and chemical properties of β-cyano ketones and transformations of α,β-unsaturated carbonyl compounds taking place in the presence of the cyanide anion and its synthetic equivalents. The state-of-the art analysis of this research field and insights for future studies are given.

An atom-efficient synthesis of hybrid molecules based on 7-azido-3-ethoxycarbonyl-1-ethyl-6-fluoroquinolin-4(1H)-one and 4-(prop-2-yn-1-yl)azolo[1,5-a]pyrimidin-7-ones by the azide-alkyne cycloaddition was developed. The synthetic approaches to precursors of hybrid molecules, 4-(prop-2-yn-1-yl)azolo[1,5-a]pyrimidin-7-ones, by alkylation of the corresponding NH-acids were optimized. Alkylation of 1,2,4-triazolo[1,5-a]pyrimidin-7-ones gave the products of alkylation at N(3) and N(4) atoms. Conditions for regioselective synthesis of N(4)-(prop-2-yn-1-yl)triazolopyrimidines were developed.

We consider the preparation of film hybrid composite materials formed by a self-assembly process via the non-covalent interactions of surface functional groups and graphene domains of graphene oxide (GO) nanosheets with anionic spin-crossover complexes [Fe^III(5Cl-thsa)₂]⁻ (5Cl-thsa²⁻ is 5-chlorosalicylaldehyde thiosemicarbazone) and cations [Et₄N]⁺ of the intercalant salt [Et₄N][Fe^III(5Cl-thsa)₂] (1). The introduction of salt 1 into the interlayer space of the GO nanosheets was observed for the first time, followed by the subsequent formation of a layered GO-1 hybrid material film, while the reversible thermally induced spin transition was maintained. The GO-1 hybrid material films were characterized by scanning electron microscopy, energy dispersive analysis, IR and Raman spectroscopy, and powder X-ray diffraction; their magnetic properties were studied. Comparative studies of the magnetic properties of complex 1 and the GO-1 hybrid material film showed the influence of the GO nanosheet matrix on the nature and completeness of the spin transition of intercalant 1. The semi-transition temperature of the GO-1 hybrid material (T_½ = 228 K) is shifted by ∼20 K towards the high-temperature region compared to that of the starting salt 1 (T_½ = 208 K).

The problem of reprocessing of used ion-exchange resins with a polystyrene-divinylbenzene matrix by oxidative degradation using the Fenton process is considered. The kinetics of the process was studied in the presence of 5–25% solutions of H₂O₂ containing catalytic additives of copper(ii;) and iron(ii;,iii) salts. Electron microscopic studies revealed characteristic changes in the surface morphology and granule shape of the ionexchange resins during oxidative decomposition.

The reaction of 4,5-dimethyl-2-(perfluoroindan-5-yl)-1H-imidazol-1-ol with aliphatic alcohols produced 6-alkoxy-substituted 2-(perfluoroindan-5-yl)-1H-imidazol-1-ols. The structures of the obtained compounds were confirmed by ¹H, ¹⁹F, ¹³C, and ¹⁵N NMR spectroscopy. NMR studies showed that 4,5-dialkyl-2-(6-alkoxy-1,1,2,2,3,3,4,7-octafluoroindan-5-yl)-1H-imidazol-1-ols demonstrated a shift in tautomeric equilibrium from the N-hydroxy tautomer in DMSO-d₆ solution toward an increase in the N-oxide form fraction in CD₃OD solution.

The catalyst for ammonia synthesis from dinitrogen and dihydrogen based on mononuclear potassium carbonyl ruthenate K₂[Ru(CO)₄] (precursor of catalytically active species) deposited on graphite-like carbon Sibunit exhibits an interesting feature when promoted with metallic potassium and BuⁿLi. Namely, the activity of the catalyst based on K₂[Ru(CO)₄]/Sibunit noticeably increases after thermal removal of CO ligands followed by short-term exposure to air compared to the activity of the standard K₂[Ru(CO)₄]/Sibunit sample not exposed to air. Unlike the latter, the air-exposed catalyst simultaneously promoted with both metallic potassium and BuⁿLi becomes much more efficient than the air-exposed catalyst promoted with metallic potassium only.