Russian Chemical Bulletin最新文献

Convenient synthesis of P(O)CH₂N-substituted bis- and tris-phosphorus-containing amines using two- and three-component systems have been developed. Methods for the synthesis of new bis- and tris-aminomethylating reagents are presented. Esters of trivalent phosphorus acids react with paraformaldehyde, alkylamines or N-substituted bis(alkoxymethyl)amines, as well as tris(butoxymethyl)amine to give new P(O)CH₂N-substituted bis- and tris-phosphorus-containing amines. The resulting compounds are of interest as water-soluble polydentate ligands and effective extractants, as well as promising biologically active substances.

A new phosphine oxide derivative, tris{2-[N-(quinolin-8-yl)carbamoylmethoxy]-phenyl}phosphine oxide, was synthesized by the alkylation of tris(2-hydroxyphenyl)-phosphine oxide. The synthesized compound exhibits the properties of a tripodal polytopic O,N ligand with respect to lanthanum and terbium cations. The composition and structures of the ligand and its complexes were determined by elemental analysis, vibrational and multinuclear NMR spectroscopy (¹H, ¹³C, ³¹P), and X-ray diffraction.

Investigations of bromination of naphtho[2,3-c][1,2,5]thiadiazole-4,9-dione revealed that the reaction proceeded most efficiently with N-bromosuccinimide in sulfuric acid and depending on the reaction conditions, can give mono-, di-, tri- and tetrabromo derivatives of naphtho[2,3-c][1,2,5]thiadiazole-4,9-dione. A series of the major isomers was isolated, and their structure was proven using heteronuclear multiple bond correlation NMR spectroscopy and high-resolution mass spectrometry.

A convenient method for the synthesis of poorly studied 4-(trifluoromethyl)thiocoumarins from 1-[2-(tert-butylthio)phenyl]-2,2,2-trifluoroethanones was developed. Thiopyranone core of 4-(trifluoromethyl)thiocoumarins was constructed by S-acylation of 1-[2-(tert-butylthio)phenyl]-2,2,2-trifluoroethanones with bromoacetyl bromide followed by treatment with triphenylphosphine to give the phosphonium salt and subsequent intramolecular Wittig reaction. S-Acylation of these substrates with acetyl chlorides bearing active methylene group and subsequent intramolecular Knövenagel condensation gave 3-substituted 4-(trifluoromethyl)thiocoumarins.

The nucleophilic substitution reaction of activated aryl dihalide was used to synthesize heat-resistant thermoplastic polymers, that is, cardo co-poly(arylene ether ketone)s (co-PAEK) with different contents of fluorene fragments. Thermomechanical and electronic properties of thin films of the copolymers were studied, taking into account the prospects of their application for the formation of an electrical contact conducting oxide—polymer-metal. Influence of charge carrier concentration and effective mobility in the polymer were revealed depending on the composition of the cardo co-PAEK in the indium—tin oxide (ITO)—co-PAEK—copper structure. The potential barrier height at the co-PAEK—copper and co-PAEK—ITO interfaces was determined, the effect of changes of the electron work function of ITO on these values was studied. Changes in the parameters of charge carriers and changes in potential barriers over time were investigated.

The reaction of equimolar amounts of Gd(CH₂SiMe₃)₃(THF)₂ and 2,6-Pr₂ⁱC₆H₃N(H)-CH₂C(CH₂Ph)₂-2-C₅H₄N (ApH) afforded the new bis(alkyl) complex ApGd-(CH₂SiMe₃)₂(THF) coordinated by the amidopyridinate ligand. The structure of the complex was determined by X-ray diffraction. The new compound and its Y- and Lu-containing analogs were studied as catalysts for the dehydrocoupling of alkoxyarenes with hydrosilanes (2: 1 molar ratio, toluene, 90 °C). The bis(alkyl) complexes ApLn(CH₂SiMe₃)₂(THF) (Ln = Y (1), Lu (2), Gd (3)) exhibited low catalytic activity in the dehydrocoupling of anisole with hydrosilanes, providing a conversion of 14–31% within 24 h. However, the use of cationic alkyl complexes, which were generated in situ from [Ph₃C][B(C₆F₅)₄] and complexes 1–3 (1: 1 molar ratio), as catalysts made it possible to significantly increase the reaction rate and the yield of dehydrocoupling products (78% within 24 h) under similar conditions. In all cases, the selective silylation of the arene substrates was observed, resulting in the formation of a new Si—C bond exclusively in the ortho position with respect to the alkoxy substituent on the aromatic ring.

The mechanism of the reaction of 7,8-dicarba-nido-undecaborane potassium salt with thioethers was studied for the first time within the framework of the electron density functional theory. The regiospecifity of the reactions involving dimethyl sulfide and methyl S-methyl-N-trifluoroacetyl-(R)-cysteinate at position B(10) of nido-carborane was substantiated by quantum chemical calculations. Evidence was obtained that the reaction of 7,8-dicarba-nido-undecaborane potassium salt with S-nucleophiles proceeded more actively in the presence of mercury(ii) chloride. The structure was optimized and the energies of intermediates were calculated at the final Toluene-CPCM-B3LYP-D3-gCP/def2-TZVP (Hg LANL2TZ) level of the theory. It was found that the key step of the reaction is the synchronous process of the B(10)—S bond formation and the hydrogen abstraction from the B(10) vertex proceeding with the participation of the mercury atom from the nido-carborane-based intermediate π-complex.

A new high-energy compound 5-((1,4-dihydro-5H-tetrazol-5-ylidene)amino)[1,2,3]-triazolo[4,5-c][1,2,5]oxadiazol-5-ium-4-ide was synthesized. It consists of a triazolofurazan core and a tetrazole cycle linked by a nitrogen bridge. Thermal stability of this compound (T_onset = 174 °C) and its dipotassium salt (T_onset = 199 °C) were studied. The structure of the compound was confirmed by X-ray diffraction.

First ferrocene- and ruthenocene-based nickel pincer complexes, NiCl[{2,5-(Bu^t₂PCH₂)₂C₅H₂}Fe(C₅H₅)] (3a) and NiCl[{2,5-(Bu^t₂PCH₂)₂C₅H₂}Ru(C₅H₅)] (3b), respectively, were synthesized and characterized by ¹H, ³¹P{¹H}, and ¹³C{¹H} NMR spectroscopy. The structure of complex 3b was established by single-crystal X-ray diffraction.

A series of N-isonicotinoyl-3(5)-ferrocenyl-5(3)-substituted 1H-pyrazoles was obtained as the mixtures of the products by acylation of tautomeric forms of 3-ferrocenyl-5-substituted 1H-pyrazoles with isonicotinoyl chloride. The rate of hydrolysis of the synthesized compounds depended on the electronic effects of the substituents in the pyrazole ring and increased in the following order Me < Ph ≈ COOEt ≪ CF₃. The hydrolysis rate of the synthesized compounds in acidic medium is significantly higher than under neutral conditions, which is associated with the possibility of the redistribution of electron density in the aromatic pyrazole ring upon the pyrazole protonation. The revealed regularities can be used for designing the redox and pH sensors, acylating agents, and antituberculosis agents active against isoniazid-resistant mycobacterium strains.