Russian Chemical Bulletin最新文献

5-(4,5-Dihydro-1H-pyrazol-3-yl)isoxazoles (pyrazoline-isoxazoles) are readily oxidized by active manganese dioxide in benzene or dichloromethane at room temperature. As a result, a simple and efficient method for the synthesis of the corresponding pyrazoleisoxazoles in 94–99% yields was developed. It was shown that 3-ethynyl-1H-pyrazoles are inactive in the 1,3-dipolar cycloaddition reaction with nitrile oxides and nitrile imines. The synthesized di- and trisubstituted pyrazole-isoxazoles showed weaker luminescent properties compared to pyrazoline-isoxazoles.

A new route for the synthesis of siloxanes containing substituents with the phosphonate and amino groups based on the catalyst-free Kabachnik—Fields reaction was developed. The synthesis was accomplished under mild conditions using 3-aminopropylsilanes, cyclic ketones, and diethyl phosphite as the starting materials to give the corresponding 1-(3-silylpropylamino)cycloalkylphosphonates in high yields.

New bifunctional composite catalysts for the Fischer—Tropsch synthesis were developed on the basis of a mixture of the Co—Al₂O₃/SiO₂ catalyst, meso-HZSM-5 hierarchical mesoporous zeolite, and boehmite binder. The mesoporous zeolite was obtained by alkaline treatment of the industrial HZSM-5 zeolite. The developed catalysts are suitable for one-pot conversion of syngas into linear C₅₊ hydrocarbons, which then undergo cracking and isomerization reactions. The effect of the concentration of NaOH solution on the porosity and catalytic efficiency of the obtained meso-HZSM-5 zeolite was studied. The performances of the bifunctional catalysts obtained from alkali-treated and pristine HZSM-5 in the conversion of syngas were compared. In the presence of the catalyst based on the alkali-treated zeolite, the total productivity to C₅₊ hydrocarbons somewhat decreases. However, the increase in the total yield of branched and unsaturated hydrocarbons provides the formation of motor fuels with high anti-knock properties.

The formation of mononuclear complexes and a heterovalent compound in the Fe^II—Fe^III—l-Ala—H₂O system was observed when using the Clark—Nikolsky oxidation potential at a temperature of 298.15 K and an ionic strength of the (Na(H)ClO₄) solution equal to 0.75 mol L⁻¹. The method of successive approximations (iteration) of the Yusupov oxidation function was used to calculate the stability and the model parameters of the mononuclear coordination compounds [FeHL(H₂O)₅]³⁺, [Fe(HL)₂(H₂O)₄]³⁺, [Fe₂(HL)₂(OH)₄(H₂O)₆]²⁺, [Fe^IIIFe^II(HL)₂(OH)₄(H₂O)₆]⁺, [FeHL(H₂O)₅]²⁺, [Fe(HL)(OH)(H₂O)₄]⁺, and [Fe(HL)(OH)₂(H₂O)₃]⁰ (L is an alanine ligand), the formation constants of these complexes, to determine the regions where they are dominant and their maximum degrees of accumulation, as well as to plot the diagrams of their distribution as a function of pH. It was determined that the heterovalent complex is the most stable and dominates up to pH 9.5.

The main pathway of the reaction of benzal and benzyl halides with phosphorus(iv) acid esters followed the dehalophosphonyl/phosphinyl(oxylation) course and led to the corresponding carbonyl-containing compounds or benzyl esters. A new reaction between α-chloro ethers and O-alkyl diethylphosphinates was discovered. The reactions of benzyl halides with esters of phosphorus(iv) and orthocarboxylic acids were catalyzed by anhydrous zinc chloride.

Reactions between the model compound N-1,4,5-trimethyl-1H-imidazole-3-oxide and electron-deficient olefins including 2-(4-methoxybenzylidene)malononitrile, (E)-ethyl-2-cyano-3-(4-methoxyphenyl)acrylate, 2-benzoyl-3-(4-methoxyphenyl)acrylonitrile, and 5-(4-methoxybenzylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione were theoretically studied in terms of the density functional theory. It was demonstrated that the reactions can proceed either by the 1,3-dipolar cycloaddition mechanism or by the Michael addition mechanism depending on the type of electron-withdrawing substituents in the olefin molecule. The reaction pathways were calculated and the intermediate structures were determined.

3-Phosphorylmethyl-3-R-indolin-2-ones were synthesized by the cascade Heck cyclization—phosphorylation of N-(2-iodophenyl)acrylamides and hydrophosphoryl compounds. In the presence of the PdCl₂/(S)-Monophos catalytic system, a racemic product was obtained; while, the (R,R)-DIOP ligand provided small chiral induction (up to 15% ee).

The sequential reaction of differently substituted 4,4,6-trimethyl-4H-pyrrolo[3,2,1-ij]-quinoline-1,2-diones with thiosemicarbazide and dimethyl acetylenedicarboxylate yielded a series of new 2-{2-[2-(4,4,6-trimethyl-2-oxo-4H-pyrrolo[3,2,1-ij]quinolin-1(2H)-ylidene)hydrazineyl]-4-oxothiazol-5(4H)-ylidene}acetates, 2-{[(1-{2-[5-(2-methoxy-2-oxoethylidene)-4-oxo-4,5-dihydrothiazol-2-yl]hydrazineylidene}-4,4-dimethyl-2-oxo-1,2-dihydro-4H-pyrrolo[3,2,1-ij]quinolin-6-yl)methyl]thio}benzoic acids, and 2-{[(1-{2-[5-(2-methoxy-2-oxoethylidene)-4-oxo-4,5-dihydrothiazol-2-yl]hydrazineyl-idene}-4,4-dimethyl-2-oxo-1,2-dihydro-4H-pyrrolo[3,2,1-ij]quinolin-6-yl)methyl]thio}-nicotinic acids. The synthesized compounds were isolated as single isomers having presumably the Z,Z configuration. Primary in vitro screening of inhibitory activity of the synthesized compounds against blood clotting factors Xa, XIa and thrombin was carried out. Efficient dual inhibitors of factors Xa and XIa and factor Xa and thrombin were identified.

The study of the reaction of 5-hydroxy-1,4,5-triphenyl-1H-imidazol-2(5H)-one with KSCN and AcOH showed that it leads to the formation of 3a,4,6a-triphenyltetrahydro-2H-imidazo[4,5-d]thiazole-2,5(3H)-dione (1a) and 2-thioxo-3a,6,6a-triphenyltetrahydro-2H-imidazo[4,5-d]oxazol-5(3H)-one (2b) with the predominant formation of the former one. The structures of compounds 1a and 2b were confirmed by X-ray diffraction analysis on the examples of solvate 1a • AcOH and monohydrate 2b • H₂O obtained by crystallization from AcOH and a mixture of EtOH—H₂O (1: 10), respectively.

New 5-[4(3)-R-phenyl]-2,2′-bipyridines bearing the 1,1,7,7-tetrakis(tert-butoxycarbonylmethyl)-1,4,7-triazaheptane (DTTA) moiety at the C(6) position (R = Cl, Br, CF₃) and their water-soluble Eu^III complexes were synthesized. The photophysical properties of the synthesized complexes were investigated. More efficient sensitization of Eu³⁺ cation luminescence was demonstrated for a number of halogen-containing ligands. Some chelates exhibited moderate cell-staining ability. The synthesized compounds did not show significant photodynamic activity, which may be due to the inhibition of the in situ generation of reactive oxygen species via the supposed interaction with the methylene moiety of DTTA-appended 2,2′-bipyridine ligands.