Vol 88, No 2 (2018)
- Year: 2018
- Articles: 30
- URL: https://journals.rcsi.science/1070-3632/issue/view/13694
Article
Phosphonic Aminocarboxylic Acids
Abstract
Methods of synthesis of phosphonic aminocarboxylic acids, ω-phosphonic analogs of monoaminodicarboxylic acids, are reviewed. Many of such compounds are ligands of ionotropic and metabotropic glutamate receptors determining the phenomenon of information processing and communication in central nervous system, important in view of prevention and treatment of Alzheimer, Huntington, and Parkinson diseases and other socially important neurodegenerative and psychoneurological diseases as well as learning and memory processes.
Influence of Solvents on the Rate of Thermal Decomposition of Peroxydecanoic Acid
Abstract
Thermal decomposition of peroxydecanoic acid has been investigated in various organic solvents. The reaction medium significantly affects the rate of peroxydecanoic acid thermal decomposition. It has been shown that primary homolytic decomposition of peroxy group is followed by induced radical chain decomposition reactions. The solvent nature influences both primary homolytic decomposition and secondary induced reactions. The correlation equations relating kinetic parameters of peroxydecanoic acid thermolysis and basic solvent properties have been derived.
Hydrogenation of Ketones and Esters Catalyzed by Pd/C‒SiO2
Abstract
Hydrogenation of unsaturated ketones and esters with molecular hydrogen on the 5%Pd/C‒SiO2 heterogeneous catalyst has been studied. The reaction direction and yield are determined by the starting compounds structure. Hydrogenation of unsaturated ketones containing phenyl group at the double carbon–carbon atom is accompanied by the reduction of the ketone group into the alcohol one. Hydrogenation of unsaturated esters is accompanied by transesterification.
Hydrogenation of Ketones on Dispersed Chiral-Modified Palladium Nanoparticles
Abstract
Hydrogenation of acetophenone and esters of ketoacids with molecular hydrogen in the presence of the Pd(acac)2–(–)-cinchonidine–H2 catalytic system has been studied. The dependence of the molar ratio of (–)-cinchonidine/Pd on size and shape of palladium nanoparticles, formed in the system, also on reaction rate and enantioselectivity has been established. The nature of the regularities observed for the Pd(acac)2–(–)-cinchonidine–H2 catalytic system was discussed.
Synthesis of Hydroxybenzoic Acids and Their Esters by Reaction of Phenols with Carbon Tetrachloride and Alcohols in the Presence of Iron Catalysts
Abstract
Alkyl esters of hydroxy-, methoxy-, and ethoxybenzoic and cresotic acids have been synthesized by reaction of phenols, anisole, phenetole, and cresols with carbon tetrachloride and alcohols in the presence of iron catalysts.
Pd2+-Catalyzed Addition of 1-Substituted Tetrazole-5-thiols to Terminal Acetylenes in Acid Medium
Abstract
Addition of 1-substituted tetrazole-5-thiols to ethyl propiolate and phenylacetylene was studied. It was found that Pd(II) salts in the presence of strong acids are effective catalysts for this reaction: the S-adducts can be obtained at relatively low temperatures in high yields. The mechanism of this reaction was suggested.
Alkylation of 1-Alkyl-3-methyl-1,4-dihydropyrazolo[4,3-c]pyrazoles with Halocarboxylic Acids Esters
Abstract
A preparative method for the synthesis of 1-alkyl-3-methyl-1,4-dihydropyrazolo[4,3-c]pyrazoles was developed. The alkylation of the obtained compounds with halocarboxylic acid esters was also investigated. A principal possibility of creating libraries of compounds based on pyrazolo[4,3-c]pyrazole derivatives was shown.
Synthesis of Fluorine-Containing Derivatives of 5-Arylisoxazoles and 4,5-Dichlorothiazole
Abstract
Alkylation of fluorophenols and phenolic aldehydes with 5-phenyl(p-tolyl)-3-chloromethylisoxazole under the Williamson reaction conditions afforded the corresponding ethers. Condensation of the resulting phenolic aldehyde derivatives and 5-phenyl(p-tolyl)isoxazole-3-carbaldehydes with p-fluoroaniline resulted in fluorine-containing azomethines. Acylation of fluorinated amines with 5-(p-tolyl)isoxazole- and 4,5- dichloroisothiazole-3-carbonyl chlorides gave rise to fluorinated amides bearing isoxazole and isothiazole fragments, representatives of which showed a synergistic effect in compositions with insecticides.
Synthesis and Wittig Reaction of Formylated (Trifluoromethylfuryl)methanephosphonates
Abstract
Methods of synthesis of 4-functionalyzed (5-trifluoromethylfur-2-yl)methanephosphonates and (5-methyl-2-trifluoromethylfur-3-yl)methanephosphonate are developed. Their formylation with ethyl formate in the presence of sodium foil is studied. Spectral characteristics of tautomers of obtained derivatives of phosphonoacetic aldehyde are evaluated. It is shown that interaction of obtained formyl derivatives with ethoxycarbonylmethylenetriphenylphosphorane regardless of the structure of the furan fragment leads to 4-furylsubstituted alkyl 4-(diethoxyphosphoryl)but-3-enoate, the abnormal product of Wittig reaction.
New Amides and Imidoamides of Maleopimaric Acid as a Chiral Dopants for Nematic Liquid Crystal Compositions
Abstract
A method for the synthesis of N-(4-alkyl, alkoxyphenyl)amides and imidoamides of maleopimaric acid was developed. Their thermal stability and optical activity were estimated. The properties of liquid crystal compositions with the synthesized compounds as chiral dopants were studied.
Features of Sulfonation of Polychlorinated Biphenyl Congeners
Abstract
Sulfonation of polychlorinated biphenyls (PCBs) and their commercial mixture (Trichlorobiphenyl) with oleum has been studied. General sulfonation patterns have been revealed for PCB congeners having no substituents in the ortho positions. The sulfonation of PCBs with chlorine atoms in only one aromatic ring gives exclusively the corresponding polychlorobiphenylmonosulfonic acids. The sulfonation of PCBs with chlorine atoms in both aromatic rings is accompanied by side formation of polychlorodibenzothiophene S,S-dioxides.
Chemical and Electrochemical Synthesis, Structure, and Properties of Metal Chelates of Tridentate N,S-Containing Azomethinazo Ligands
Abstract
Novel Cu(II), Co(II), Ni(II), and Zn(II) complexes of 5-methyl-2-phenyl-4-[(4-phenylazo)anilinemethylylidene]- 2,4-dihydro-3H-pyrazole-3-thione and 5-methyl-4-[4-methyl-2-(4-methylphenylazo)anilinemethylylidene]- 2-phenyl-2,4-dihydro-3H-pyrazole-3-thione, i.e. ligands containing the phenylazo group in the ortho and para positions of the aniline fragment, were synthesized by the chemical and electrochemical methods. The complexes and ligands were characterized by IR, 1H NMR, X-ray absorption spectroscopy and magnetochemistry. The azo group of the ligands is not involved in coordination to the metal.
Synthesis and Characterization of Zn(II) Complexes of 2-(7-Bromo-2-oxo-5-phenyl-2,3-dihydro-1H-1,4-benzodiazepin-1-yl)acetohydrazide and Its Condensation Products with Pyruvic Acid and Isatin
Abstract
The systems ZnCl2–2-(7-bromo-2-oxo-5-phenyl-2,3-dihydro-1H-1,4-benzodiazepin-1-yl)acetohydrazide (Hydr)–propan-2-ol, ZnCl2–Hydr–pyruvic acid (HPv), and Zn(CH3COO)2–Hydr–isatin(HIz)–propan-2-ol were studied. Optimal synthesis conditions were determined, and the complexes [Zn(Hydr)2Cl2], [Zn(HydrHPv)2Cl2], and [Zn(HydrIz)2] were isolated. The complexes were characterized by elemental analysis, thermogravimetry, IR spectroscopy, and mass spectrometry. The electrical conductivities of the complexes were measured. The local environment of the central atom in the coordination entity was determined by X-ray absorption spectroscopy.
Effect of Structure of Polymeric Nickel Complexes with Salen-Type Ligands on the Rate of Their Electroactivity Decay in Solutions of Water-Containing Electrolytes
Abstract
The influence of the structure of diimine bridge in the Schiff’s bases (derivatives of N,N'-ethylenebissalicylimine) on the rate of the loss of electroactivity of their complexes with nickel in acetonitrile containing 0.1 M of tetraethylammonium tetrafluoroborate (anhydrous and upon addition of 1 wt % of water) has been studied. It has been shown that the presence of bulky yet light methyl groups in the structure of diimine bridge significantly reduced the loss of electroactivity (37% of the initial capacity retained after 50 cycles) as compared to the ligand containing no substituents and containing phenyl group as the substituent (17 and 20%, respectively, of initial capacity retained after 50 cycles).
Synthesis of Water-Soluble Silver Selenide Quantum Dots Luminescing within the Transparency Window of Biological Tissues
Abstract
Water-soluble aggregation-resistance nanocomposites based on silver selenide quantum dots with an average particle size of 11.4–12.7 nm and the natural polysaccharide galactomannan were synthesized for the first time using a simple environmentally benign method for the generation of highly reactive selenide ions acting as selenating agent. The obtained nanocomposites showed luminescence in the transparency range of biological tissues (λ ~705 nm) and were characterized in detail by X-ray powder diffraction, transmission electron microscopy, and absorption and luminescence spectroscopy.
Synthesis of Nickel Nanoparticles by the Reduction of Its Salts Using the Modified Polyol Method in the Presence of Sodium Polyacrylates with Various Molecular Weights
Abstract
Nickel nanoparticles were synthesized by the reduction of its salts by hydrazine hydrate in a polyol medium in the presence of sodium polyacrylates with molecular weights of 1200, 5100, and 8000. The nanoparticles were characterized by X-ray diffraction, scanning and transmission electron microscopy, IR spectroscopy, and thermogravimetric analysis. The effect of the synthesis conditions, such as temperature, molecular weight of sodium polyacrylate, and polyol and precursor types, on the reduction products were studied. It was shown that the average particle sizes, their aggregation and polydispersity degrees increase as the polymer molecular weight increases.
Features of the Formation of Thin Films of Supersaturated CdxPb1–xS Solid Solutions by Chemical Bath Deposition
Abstract
Thin nanostructured films of lead sulfide-based CdxPb1–xS solid solutions, strongly supersaturated with respect to the substituting component, were prepared by hydrochemical deposition from ammonia-citrate, ethylenediamine-citrate, and ethylenediamine reaction mixtures onto glass-ceramic substrates. The structure, composition, and morphology of the resulting films were examined. An interesting feature of the synthesis was revealed, a distinct correlation between the linear dimensions of the crystallites constituting the films and the cadmium sulfide content therein: the higher cadmium sulfide content, the smaller were the crystallites.
Synthesis and Characterization of Disulfide-Schiff Base Derivatives and in vitro Investigation of Their Antibacterial Activity Against Multidrug-Resistant Acinetobacter baumannii Isolates: A New Study
Abstract
In this study two different methods without a catalyst and with a CeO2 nano catalyst were used for the synthesis of dimeric disulfide-Schiff bases. The dimeric disulfide-Schiff base derivatives were characterized by FT-IR, NMR, and MS spectra, and elemental analysis. The disulfide-Schiff bases and their derivatives 2–5c were screened for in vitro antibacterial activity against 40 multidrug-resistant strains of Acinetobacter baumannii, and their minimum inhibitory concentrations were determined. Most of products exhibited high antibacterial activity against Acinetobacter baumannii.
Design, Synthesis, and Cytotoxicity of Semisynthetic Betulinic Acid-1,2,4-Oxadiazole Amide Derivatives
Abstract
Biological activity of betulinic acid derivatives containing a 1,2,4-oxadiazole ring prompted us to synthesize betulinic acid-1,2,4-oxadiazole amide derivatives 14–25 starting with the amide coupling reaction of betulinic acid 1 and (3-aryl-1,2,4-oxadiazol-5-yl)methanamines 2–13. The products were tested for cytotoxicity on three human cancer cell lines in vitro. All tested compounds demonstrated high activity. The structures of the synthesized compounds were elucidated from IR, NMR and mass spectra.
Hydrogen-Bond Directed Cyanide-Bridged Supramolecular 2D and 1D Bimetallic Coordination Polymers: Synthesis, Crystal Structure, and Magnetic Properties
Abstract
By using K2[Ni(CN)4] as a building block and two Mn(III) compounds containing bicompartimental Schiff-base ligands as assembling segments, two new cyanide-bridged Ni–Mn complexes of the formula {[Mn(L1)(H2O)]4[Ni(CN)4]}[ClO4]2·2CH3CN (1) and {[Mn(L2)(H2O)]2[Ni(CN)4]}·CH3CN H2O (2) (L1 = N,N’-1,2-propylene-bis(3-methoxysalicylideneiminate; L2 = N,N’-1,2-propylene-bis(3-ethoxysalicylideneiminate) have been synthesized and characterized by elemental analysis, IR spectroscopy and X-ray analysis. Single Xray diffraction analysis revealed the cationic pentanuclear and neutral trinuclear structures for complexes 1 and 2, respectively, and indicated that the structure of the Schiff-base ligand had obvious influence on the structural types of the target cyanide-bridged complexes. Both cyanide-bridged complexes are self-complementary via coordinated aqua ligand from one complex and the free O4 compartment from the neighboring complex, therefore giving supramolecular two-dimensional network and one-dimensional zig-zag chain structure. Study of magnetic properties revealed weak antiferromagnetic coupling within the Mn2 dimer formed by the intermolecular hydrogen bond.
On the Feasibility of the Use of the Concept of the Oxidation State of an Atom for the Selection of Stoichiometric Coefficients in Redox Reaction Equations
Abstract
The questions relating to the use of two alternative methods for the selection of stoichiometric coefficients in redox reaction (ROR) equations, namely, the electron balance method and the ion‒electron balance method, have been considered and discussed. It has been stated that, in the first of these methods, one should always determine the degree of oxidation of the chemical elements forming the ROR participants, which is a formal concept and often leads to ambiguous conclusions. By contrast, the second method deals with real chemical objects and is free from this shortcoming. A series of examples that illustrate the use of the ion‒electron balance method in inorganic and organic chemistry have been presented.
Application of Hydroacoustic Treatment for Intensification of Alkaline Deacetylation of Chitin
Abstract
The efficiency of the hydroacoustic impact produced by a rotor-stator device for intensification of the chitin deacetylation process was studied. Preliminary mechanical activation of an aqueous suspension of chitin was found to decrease the reaction time more than by half and strongly decrease the molecular weight loss of the polymer.
Crown Ether–SiO2–TiO2 Composites in the Sorption of Metal Ions from Acidic Aqueous Solutions
Abstract
Crown ether–SiO2–TiO2 composites were obtained by adding crown ethers (dibenzo-18-crown-6 or dibenzo-21-crown-7) during the sol–gel synthesis of SiO2–TiO2. The behavior of the composites in the sorption of several alkali, alkaline-earth, and rare-earth metal cations from acidic solutions was investigated. The crown ether–SiO2–TiO2 composites of the crown ethers showed higher efficiency and selectivity in the sorption of barium cations, as well as ytterbium cations in the presence of Sr(II), Ce(III), La(III), and Nd(III) compared to the parent crown ethers. It was established by FTIR spectroscopy that the crown ether molecule immobilized on the oxide surface has a distorted structure, which can explain the change in the selectivity of complex formation in going from crown ethers to their composites.
Modern Advances in the Preparation and Modification of Cellulose Nitrates
Abstract
The published data on the preparation of cellulose nitrate are summarized. New sources of cellulosic materials are analyzed. The results of studies on the chemical modification of cellulose nitrate by nucleophilic substitution are presented. The published data on the plasticization of cellulose nitrate are summarized. Modern plasticizing systems and methods for their effectiveness assessment are described.
Letters to the Editor
Synthesis of New Unsaturated Amines by The Stevens Rearrangement
Abstract
Monoalkylation of 1,4-dichlorobut-2-ene with prop-2-yn-1-ol under phase-transfer catalysis conditions led to the formation of 1-(prop-2-yn-1-yloxy)-4-chlorobut-2-ene. The latter reacted with dimethylamine to afford N,N-dimethyl-4-(prop-2-yn-1-yloxy)but-2-enyl-1-amine. Its quaternization afforded new ammonium salts containing 4-(prop-2-yn-1-yloxy)but-2-enyl group. Unsaturated tertiary amines formed as a result of Stevens 3,2-rearrangement of quaternary salts.
Synthesis and Some Transformations of Cyclic Acetals of Propargyl Aldehyde
Abstract
Dehydrobromination of 2-(1,2-dibromoethyl)-1,3-dioxocyclanes with sodium amide in liquid ammonia provided cyclic acetals of propargyl aldehyde. Reactions of the resulting compounds with nitrile oxides and diazomethane afforded the corresponding isoxazole and pyrazole derivatives.
Synthesis of 4-Aryl-2-hydroxy-4-oxo-N-{4-[(1,3-thiazol-2-yl)- sulfamoyl]phenyl}but-2-eneamides
Abstract
The reaction of methyl aroylpyruvates with 2-(4-aminobenzenesulfamido)thiazole (norsulfazole) in glacial acetic acid in the presence of anhydrous sodium acetate furnished 4-aryl-2-hydroxy-4-oxo-N-{4-[(1,3-thiazol-2-yl)sulfamoyl]phenyl}but-2-eneamides.
Spectral Luminescent Properties of 2-Aryl-5-(2,6-dimethoxyphenyl)-1H-1,3,4-oxadiazoles
Abstract
2-Aryl-5-(2,6-dimethoxyphenyl)-1H-1,3,4-oxadiazoles were synthesized by cyclization reaction of benzoylbenzohydrazides in SOCl2, and their spectral luminescent properties were studied. The oxadiazoles containing phenyl or o-methoxyphenyl substituents in the position 2 were shown to luminesce with a high quantum yield in polar and nonpolar solvents. The replacement of these substituents by 2-hydroxyphenyl group led to oxadiazole intensely emitting only in highly polar aprotic DMSO.