Том 86, № 11 (2016)
- Год: 2016
- Статей: 31
- URL: https://journals.rcsi.science/1070-3632/issue/view/13465
Article
Solubility of d-elements salts in organic and aqueous-organic solvents: IV. Solubility of cadmium chloride
Аннотация
Solubility of cadmium chloride at 25°C in four ternary systems containing mixed water-organic solvents was measured by the isothermal saturation method. Dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide, and 1,4-dioxane were used as organic components. In all systems the organic component addition provides a salting-out effect within the whole range of the binary solvent compositions.
P/RS intergrowth type phases in the Ln2O3–MO–Al2O3 systems
Аннотация
Regularities of formation of complex aluminates with structure of P/RS intergrowth type phases in the Ln2O3–MO–Al2O3 systems (Ln = rare-earth element, M = Mg, Ca, Sr, Ba) have been considered. Systematization of the data on formation of complex compounds coexisting with one-layer phases in the Ln2O3–MO–Al2O3 systems and analysis of geometry criteria of LnMAlO4 stability is a promising approach to prediction of novel compounds with structure of Ruddlesden–Popper phase.
Phenomenon of isoparametricity in reactions of trans-2,3-diaryloxiranes with arenesulfonic acids. Mechanistic interpretation
Аннотация
Nonadditive effects of substituents X and Y are manifested in reactions of symmetrically X-substituted trans-2,3-diaryloxiranes with Y-substituted arenesulfonic acids. The isoparametric point is reached experimentally: close to the point τXIP = 4.73 on substituent Х the rate of the oxirane ring opening of trans-2,3-bis(3-bromo-5-nitrophenyl)oxirane (τX = 4.38) practically does not depend on substituent Y (ρYX = 0.10±0.05). The results of cross correlation analysis of the kinetic data are applied to interpretation of the mechanism of the studied reactions.
Synthesis of 1,3,4,6-tetraoxo compounds
Аннотация
The two-step method of synthesis of 1,3,4,6-tetraoxocompounds with different terminal substituents is developed. By condensation of alkyl methyl ketones with dimethyl oxalate new 1,6-dialkyl-substituted 1,3,4,6-tetraoxohexanes are obtained. The esters of 3,4,6-trioxoalkanoic acids are synthesized by the condensation reaction of alkyl acetates with dialkyl oxalates and alkyl methyl ketones. By the reaction of ethyl acetate with diethyl oxalate and methyl acetate the mixed diester of 3,4-dioxo-1,6-hexanedioic (ketipic) acid has been first prepared. Specific structural features of the synthesized compounds are discussed basing on the data of the IR, NMR, and XRD diffraction (XRD) analysis.
Synthesis, structure, and antimicrobial activity of N,6-diaryl-4-methyl-2-oxo-1,2,3,6-tetrahydropyrimidine-5-carboxamides
Аннотация
Reactions of acetoacetic acid N-arylamides with aromatic aldehydes and urea led to the formation of N,6-diaryl-4-methyl-2-oxo-1,2,3,6-tetrahydropyrimidine-5-carboxamides. Structure and antimicrobial activity of the compounds obtained were examined.
New reactions of benzocaine
Аннотация
Reaction of benzocaine with indane-1,3-dione-2-carbaldehyde afforded the corresponding azomethine. Ethoxymethylenemalonate reacted with benzocaine to form ethyl 4-{[2-(ethoxycarbonyl)-4-methoxy-3-oxobuten-1-yl]amino}benzoate, which was converted to the corresponding quinolone when heated to 185–190°C. Reactions of benzocaine with aliphatic aldehydes furnished 2,3-alkyl-substituted quinolines.
Phosphorylation of aminomalonates
Аннотация
The reactions of chloroethynylphosphonates with aromatic secondary aminomalonates occur as classic nucleophilic substitution of chlorine atom at the sp-hybridizied carbon atom to form new phosphorylated 2-arylaminomalonates, diethyl esters of 2-(diethoxyphosphorylethynyl)-2-arylaminomalonic acids. Nonobservance of chemo- and regioselectivity was revealed when using cyclohexyl- and benzylaminomalonates.
Diastereotopic derivatives of chiral alkoxyisoindolinones
Аннотация
A method for synthesis of 2,3-substituted 3-hydroxyisoindolin-1-one acyl derivatives, modified reactivators of tumor suppressor protein p53, was developed; these compounds were synthesized and characterized. It was shown that diastereomeric esters of Boc-N-protected amino acids, unlike esters with a free amino group, can be preparatively isolated by flash chromatography using achiral media.
Ethyl 2-bromomethyl-5-(1,2,3-thiadiazol-4-yl)furan-3-carboxylate in reactions with O-, S-, N-, and P-nucleophiles
Аннотация
Reaction of ethyl 2-bromomethyl-5-(1,2,3-thiadiazol-4-yl)furan-3-carboxylate with nucleophiles of different nature was studied. It is shown that substitution of bromine with acetoxy group takes place under the action of sodium acetate in the acetic acid. Stronger bases, like phenolates, cause considerable decomposition of the labile furylthiadiazole fragment Decomposition can be avoided only when this reaction is carried out in the presence of a phase transfer catalyst under the conditions of the ion pair extraction,. In the reaction with sodium N,N-diethyl dithiocarbaminate the corresponding thioester is formed. Butanethiol and thiophenol are alkylated as potassium thiolates. In the last case S-alkylation proceeds exclusively. Reaction with excess 2-aminoethanol permits to prepare secondary amine, and the reactions with pyrrolidine, piperidine, and morpholine give the corresponding tertiary amines. Phosphorylation with triethyl phosphite under the conditions of Arbuzov reaction leads to the corresponding diethyl phosphonate. In all these transformations furylthiadiazole fragment is retained.
Reactions of α-carbanions of lithium acylates with N,N-diethyl-N-chloro- and N,N-diethyl-N-bromoamines
Аннотация
The interaction of α-carbanions of lithium acylates (prepared via metalation of acetic, butyric, or isobutyric acid with lithium diisopropylamide in tetrahydrofuran under argon atmosphere) with N,N-diethyl-N-chloro- or N,N-diethyl-N-bromoamine has resulted in the formation of succinic acid or its 2,3-diethyl- and 2,2,3,3-tetramethyl-substituted derivatives in yields of 47–66% and the corresponding α-halocarboxylic acids (12–34%). Anion–radical scheme of the reaction products formation has been suggested.
Chiral acyclic diaminocarbene complexes of palladium(II) immobilized on a polymeric support as promising catalysts of the Suzuki reaction
Аннотация
Metal-promoted nucleophilic addition of primary amino group of a natural L-amino acid anchored on polystyrene support to coordinated isonitrile substrate has afforded preparation and simultaneous immobilization of chiral acyclic diaminocarbene complex of palladium(II). The obtained catalytic system is stable under conditions of the Suzuki reaction and demonstrates good catalytic activity in the reaction with a sterically hindered substrate.
Novel organoantimony compounds [2,6-(OMe)2C6H3]3SbO and [2,6-(OMe)2C6H3]3Sb(NCO)2·0.5(CH3)2CO. Synthesis and structure
Аннотация
Novel organic compounds of antimony(V), tris(2,6-dimethoxyphenyl)antimony diisocyanate and oxide, have been prepared and studied by X-ray diffraction analysis. Antimony atoms in the diisocyanate molecule and in two symmetrically independent molecules of the oxide exhibit trigonal-bipyramidal and tetrahedral coordination, respectively.
Synthesis and structure of 3-{[aryl (hetaryl)amino]methylene}chromane-2,4-diones and their metal complexes
Аннотация
3-{[Aryl(hetaryl)amino]methylene}chromane-2,4-diones (HL) were synthesized and used for chemical and electrochemical synthesis of Cu(II), Ni(II), and Co(II) complexes of the general formula ML2, as well as the ZnLOOCCH3 complex. The structure of the complexes was studied by IR, 1Н NMR, and X-ray absorption spectroscopy. Density functional theory (DFT) calculations showed that the energetically most favored form of compounds HL is an aminoketone tautomeric form. The crystal structure of the solvate of bis-{3-[(4-methylanilinato)methylene]chromane-2,4-dionato}copper(II) with two DMF molecules was determined by X-ray diffraction analysis.
Nucleophilic substitution in 4-bromo-5-nitrophthalonitrile: XIV. Synthesis and properties of 4,5-bis[4-(1-methyl-1-phenylethyl)phenoxy]phthalonitrile and phthalocyanines therefrom
Аннотация
4,5-Bis[4-(1-methyl-1-phenylethyl)phenoxy]phthalonitrile was prepared by the nucleophilic substitution of the nitro group and bromine in 4-bromo-5-nitrophathalonitrile. The product was used to synthesize the corresponding octasubstituted phthalocyanine, as well as its magnesium, copper, zinc, cobalt, and nickel complexes. The spectral properties of the synthesized phthalocyanines were studied.
Influence of ligand donor-acceptor properties on the structure, optical, and electrochemical characteristics of Ir(III) complexes with cyclometallated 2-phenylbenzotiazole
Аннотация
The cis-C,C-structure of a series of cyclometallated Ir(III) complexes with 2-phenylbenzotiazole was determined by the methods of X-ray diffraction (XRD) analysis, 1H, 13C, 31P NMR, and IR spectroscopy. Long-wave absorption bands, phosphorescence, and processes of electrochemical oxidation and reduction of the complexes were assigned to the transfer of electrons presumably located on dπ and π* orbitals of cyclometallated 2-phenylbenzotiazole. The decrease in donor and acceptor properties of the ligands leads to the blue shift of absorption spectra and phosphorescence and to the anodic shift of oxidation and reduction potentials of the complexes.
Quantum-chemical study of lutetium and ytterbium bis- and tetrakis(phthalocyaninates)
Аннотация
DFT calculations with B3LYP and PBE0 functionals have been carried out to determine the structural parameters, vibrational frequencies, and quadrupole moments of double-decker heavy lanthanide phthalocyaninates Pc2Lu, (Pc2Lu)+, (Pc2Lu)–, Pc2Yb, (Pc2Yb)+, and (Pc2Yb)–. Free valence of the Pc moiety [0.5 in Pc2Lu and Pc2Yb; 1.0 in (Pc2Lu)+ and (Pc2Yb)+] is delocalized in small fractions over the carbon atoms. The Pc2Lu и Pc2Yb molecules have a high electron affinity (3.2 eV) and a low ionization potential (6.1–6.3 eV). Calculations predict formation of quadruple-decker supercomplex Yb(Pc2Lu)2 from two Pc2Lu molecules and an Yb atom via an exothermic process. The equilibrium structure of the molecules and ions can be characterized by D4d point symmetry group.
Effect of poly(ethylene oxide) on the kinetics of oxidative polymerization of aniline
Аннотация
The kinetics of polymerization of aniline hydrochloride in aqueous poly(ethylene oxide) solution in the presence of ammonium persulfate have been studied. The order of the catalytic step has been found to change from first to second when the molecular weight of poly(ethylene oxide) reaches a certain value. Adsorption equilibrium is rapidly established between the monomer and its oxidation products which give rise to a new phase and exert a catalytic effect.
Computer modeling of triterpene glycosides interaction with natural polymer chitosan
Аннотация
By means of computer modeling, the main regularities of the interaction of triterpene saponins with chitosan are revealed. It is shown that the sorption of glycosides changes the ordered configuration of chitosan, and the complex of chitosan with saponin, the derivative of quillaic acid, is more stable than the complex with the derivative of oleanolic acid. The formation of complexes occurs due to electrostatic, hydrophobic interactions, and hydrogen bonds, whose strength is determined by the nature, geometry, and specific structure of terpenes of the β-amyrin series.
Synthesis of chemical compounds of chitosan with betulin under nearly homogeneous conditions
Аннотация
Chemical compounds of chitosan with betulin have been synthesized with the use of chitosan gels in alcoholic and acetic acid dispersions under nearly homogeneous conditions. The resulting biphilic compounds contain up to one betulin residue per 2–3 chitosan units. The formation of chemical compounds of chitosan with betulin has been confirmed by several physicochemical methods. The procedure developed for the preparation of chitosan gels with alcohol-containing dispersion medium makes it possible to carry out chitosan reactions with compounds poorly soluble in aqueous and acetic acid media.
Synthesis of gelatin-stabilized concentrated hydrosols of copper nanoparticles
Аннотация
The effect of the copper sulfate, hydrazine, and gelatin concentrations, as well as of the Bloom strength of gelatin, pH, and synthesis temperature on the formation of copper nanoparticles via copper(II) sulfate reduction with a hydrazine solution has been evaluated. Conditions for the formation of oxidation- and aggregation-resistant concentrated (up to 0.4 M) copper metal hydrosols have been found. According to the transmission electron microscopic data, the resulting hydrosols contain metallic copper nanoparticles shaped as polyhedra with six poorly defined facets, having an average size of 30–60 nm, stabilized by a gelatin layer (2–3 nm).