Том 87, № 2 (2017)
- Год: 2017
- Статей: 37
- URL: https://journals.rcsi.science/1070-3632/issue/view/13536
Article
Reaction of [Pt(NH3)4]Cl2·H2O with (NH4)6Mo7O24·4H2O in an aqueous alkaline solution at 190°C (autoclaving conditions)
Аннотация
A solid product formed during thermolysis of tetraammineplatinum(II) chloride and ammonium heptamolybdate in an aqueous alkaline solution under autoclaving conditions has been studied by means of dynamic light scattering, scanning electron microscopy, X-ray diffraction analysis, and elemental analysis. The amount of free ammonia formed in the reaction has been determined by titration. The pathway of platinum(II) and heptamolybdate ions reduction by inner-sphere ammonium into the corresponding metals has been proposed.
Synthesis and thermal transformation of multi-component layered double MgCo/AlFe hydroxides with hydrotalcite srtucture
Аннотация
A series of multi-component layered double hydroxides with hydrotalcite structure containing doubly charged magnesium and cobalt cations and triply charged aluminum and iron cations in the brucite-like layers have been synthesized by co-precipitation at variable pH. Formation of the hydrotalcite structure has been confirmed by X-ray diffraction analysis. Thermal behavior of the synthesized samples has been studied by IR spectroscopy, thermogravimetry, and differential thermal analysis.
Structure, magnetic, and electrical properties of bismuth niobates doped with d-elements: XIV. Magnetic behavior of Bi2BaNb2–2xFe2xO9–δ solid solutions
Аннотация
Magnetic susceptibility and ESR properties of iron-containing Bi2BaNb2–2xFe2xO9–δ solid solutions with layered perovskite-like structure have been studied. In the diluted solid solutions, iron atoms are combined into Fe(III) dimers and tetramers with antiferro- and ferromagnetic exchange types. The exchange parameters and the distribution of aggregates in the solid solutions have been calculated as functions of the paramagnetic atoms fractions.
Phase transitions in mixed-layer Aurivillius phases
Аннотация
The Aurivillius phases Bi7Ti4NbO21, CaBi8Ti7O27, and SrBi8Ti7O27 were synthesized by solid-phase reactions. The results of high-temperature X-ray diffraction and thermal analyses of certain Aurivillius phases are presented. Principal regularities of thermal expansion of the synthesized compounds are established. A correlation between the Curie temperature and the structure of the compounds was found.
Synthesis, structure, and photocatalytic properties of titanium(IV) oxide modified with silver oxide nanoparticles on a boron-containing mesoporous support
Аннотация
A method for the synthesis of TiO2–B2O3–Ag composite has been proposed. The composite structure and phase composition have been determined by X-ray diffraction analysis, IR spectroscopy, and scanning as well as transmission electron microscopy. The introduction of boron oxide in the TiO2–Ag composite enhances catalytic activity of the samples in the reactions of methyl orange photodecomposition.
Neural network modeling. Dissociation of acetic and benzoic acids in aqueous-organic solvents
Аннотация
Predictive correlation-regression and neural network models for description of the properties of aqueous-organic solvents on the strength of acetic and benzoic acids have been developed. Significant descriptors affecting the dissociation equilibrium of the acids have been found. The features of the solvation (reflected in the electrostatic, cohesion, and electron accepting interactions) on the acids strength have been disclosed. Prediction of the dissociation constants of acetic and benzoic acids has been successfully performed using a three-layer perceptron. Prospects of the neural network modeling for prediction of organic acids strength in aqueous-organic media have been demonstrated. A neural network classifier of acetic and benzoic acids strength based on the aqueous-alcoholic solvents descriptors has been developed and trained.
Tristimulus colorimetric and spectrophotometric study of the state of 4-hydroxystyryl dyes in aqueous solutions
Аннотация
Acid-base properties of 4-hydroxystyryl dyes in aqueous solution have been studied by means of chemical tristimulus colorimetry and spectrophotometry. Ionization and hydroxylation constants of the dyes have been determined using chromaticity functions of specific and CIE color difference. It has been shown that aggregation processes in the solution of 4-hydroxystyryl dyes can be observed by means of tristimulus colorimetry. A scheme of acid-base transformations of the studied dyes in the solution has been suggested, and selected spectrophotometric parameters of the equilibrium ionic and molecular forms have been determined.
On the mechanism of autocatalytic thermal decomposition of some secondary nitramines
Аннотация
Mechanism of autocatalytic action of picric acid during thermal decomposition of N,2,4,6-tetranitro-Nmethylaniline has been studied for the first time. The process occurs as nucleophilic substitution of N,2,4,6-tetranitroanilinium ion with picrate one to form N,2,4,6-tetranitroaniline and trinitroanisole. In contrast to the case of aromatic nitramines, thermal decomposition of secondary alkylnitramines is accompanied by acid-base catalysis.
Epoxidation of tetracyclodecene hydrocarbons with the H2O2·CO(NH2)2 adduct in the presence of heteropoly compounds containing rare-earth metal cations
Аннотация
Epoxidation of tetracyclododecene bridged hydrocarbons prepared via the [4+2]-condensation of bicyclo[2.2.1]hept-2-ene and its alkyl derivatives with cyclopentadiene in the presence of Н-form of synthetic mordenite has been studied. Phosphorus-molybdenum and phosphorus-tungsten heteropoly compounds doped with Co3+, Gd3+, Nd3+, Ce(4–x)+ (x = 0, 1) cations as well these compounds deposited on highly disperse carbon material have exhibited high activity in epoxidation of the synthesized hydrocarbons under the action of the H2O2·CO(NH2)2 adduct. Structures of the new bridged polycyclic epoxides have been elucidated by IR as well as 1Н and 13С NMR spectroscopy.
Crystal structure of hydrobromides of pyridines and quinolines N-oxides
Аннотация
Structures of hydrobromides of quinoline, 4-methylquinoline, pyridine, and 4-methylpyridine N-oxides have been elucidated by means of X-ray diffraction analysis. In contrast to other salts, quinoline N-oxide hydrobromide crystallizes in the form of dimer with two water molecules. The oxygen atom of the organic molecule is coordinated with water protons, and its state is close to sp2-hybridization. In the cases of other hydrobromides, the oxygen atom is strongly bound to the proton of НBr and exhibits sp3-hybridization.
Bis(4-nitrophenyl)phosphorylazide as a reagent for direct azidation of polyfunctional derivatives of pyrimidin-4(3Н)-one
Аннотация
The application of bis-(4-nitrophenyl)phosphorylazide–1,8-diazabicyclo[5.4.0]undec-7-ene system for direct transformation of polyfunctional derivatives of pyrimidin-4(3H)-one in the corresponding 4-azidopyrimidines has been suggested for the first time. Using this system, novel 4-azido-6-(2,6-dihalo-α-methoxybenzyl)-5-methyl-2-(nitroamino)pyrimidines have been obtained in good yield under mild conditions.
Synthesis of 3-oxoesters and functional derivatives of pyrimidin-4(3Н)-one based on 1-(2,6-dihalophenyl)cyclopropan-1-carboxylic acids
Аннотация
Special features of the synthesis and chemical transformations of novel functional derivatives of 6-[1-(2,6-dihalophenyl)cyclopropyl]pyrimidin-4(3H)-one and ethyl esters of 3-[1-(2,6-dihalophenyl)cyclopropyl]-2-methyl-3-oxopropanoic acids prepared from 2-(2,6-dihalophenyl)acetonitriles have been revealed. Novel achiral structural analogs of experimental anti-HIV agent МС-1501 have been synthesized.
Alkylation of 4-(phenylthio)-1H-pyrazol-5-ols with methyl bromoacetate
Аннотация
Alkylation of 4-(phenylthio)-1H-pyrazol-5-ols with methyl bromoacetate has afforded a series of phenyl pyrazolyl sulfides which have been oxidized into sulfones. The resulting esters have been hydrolyzed into the corresponding acids. The synthesized compounds potentially exhibit biological activity.
Synthesis and properties of 2,5-bis(furan-2-yl)-1H-imidazole
Аннотация
2,5-Bis(furan-2-yl)-1H-imidazole was synthesized by the Weidenhagen reaction of [2-(furan-2-yl)-2-oxoethyl]acetate with furfural. Alkylation of the title compound with methyl iodide in acetone in the presence of potassium hydroxide gave a mixture of isomeric N-methyl derivatives, 2,5-bis(furan-2-yl)-1-methyl-1H-imidazole being the major one. Electrophilic substitution reactions of the latter (nitration, bromination, sulfonation, hydroxymethylation, and acylation) were studied.
1,3-oxazole derived cytisines
Аннотация
Reactions of 1-acylamino-2,2-dichloroacrylonitriles, diethyl 1-acylamino-2,2,2-trichloroethyl-phosphonates and 1-acylamino-2,2-dichloroethenylphosphonium salts with natural alkaloid cytisine have been studied. A series of novel multifunctional cytisine derivatives containing pharmacophore 1,3-oxazole moiety have been obtained. Composition and structure of the synthesized compounds have been confirmed by mass spectrometry and NMR spectroscopy data.
Disulfide derivatives of thiosemicarbazones of 4-formyl-5-thiopyrazole
Аннотация
The reaction of 4-formyl-5-mercaptopyrazole with thiosemicarbazides in methanol has afforded novel disulfide derivatives of thiosemicarbazones, and their structure has been studied by NMR and IR spectroscopy. X-ray diffraction analysis of [5,5'-dithiobis(4-formyl-3-methyl-1-phenylpyrazole)]-4-allylthio-semicarbazone has shown that it exists as a dimer with two molecules linked via the disulfide S–S bridge between the heterocycles in the crystal.
Thiadiazole ring opening in the derivatives of 2-substituted 5-(1,2,3-thiadiazol-4-yl)-3-furoic acid under the action of bases
Аннотация
Transformations of the derivatives of 2-substituted 5-(1,2,3-thiadiazol-4-yl)-3-furoic acid under the action of bases has been studied. In the presence of potassium tert-butylate in THF, the studied compounds decompose with the cleavage of the thiadiazole ring, liberation of nitrogen, and formation of labile acetylene thiolates. In the presence of methyl iodide, these salts form stable 2-methylthioethynylfurans. Under the action of sodium ethylate in ethanol, thiadiazole ring of ethyl [2-methyl-5-(1,2,3-thiadiazol-4-yl)]-3-furoate is split to form the corresponding sodium acetylene thiolate. Under the action of ethanol, two molecules of this salt give bis(furyl)dithiafulvene. In the DMF–potassium carbonate system, acetylene thiolates react with primary and secondary amines giving thioamides of (4-ethoxycarbonyl-5-methylfur-2-yl)acetic acid. Treating of ethyl 2-methyland 2-N-morpholinomethyl-5-(1,2,3-thiadiazol-4-yl)-3-furoates with hydrazine hydrate leads to hydrazinolysis of the ester group and cleavage of thiadiazole ring resulting in the formation of hydrazides of 4-hydrazinocarbonylfur-2-ylacetic acid. In the case of ethyl 2-acetoxymethyl- and 2-(4-nitrophenoxy)methyl-5-(1,2,3-thiadiazol-4-yl)-3-furoates, thiadiazole ring is retained and exclusively hydrazinolysis of the ester groups is observed.
Synthesis of P,N-protected phosphinic pseudoprolylglycine block
Аннотация
The phosphine block N-Cbz-Pro-ψ[P(O)(OAd)CH2]-GlyOH has been synthesized for subsequent peptide assembly. A procedure has been proposed for the preparation of phosphorus prolylglycine isostere by three-center two-component amide version of the Kabachnik–Fields reaction. A combination of amide and carbonyl fragments in the molecule of 4-N-Cbz-aminobutyraldehyde makes it possible to accomplish cyclization with generation in situ of a cyclic pyrrolidine Schiff base, followed by Arbuzov phosphorylation of the latter with diacetyl 2-(ethoxycarbonyl)ethyl phosphonite generated in situ.
Supramolecular inclusion complexes of β-cyclodextrin with 4-(acyloxy)-4-(cyclopropylethynyl)-1-(2-ethoxyethyl)piperidines
Аннотация
4-Acyloxy-4-(cyclopropylethynyl)-1-(2-ethoxyethyl)piperidines have been synthesized by reaction of 1-(2-ethoxyethyl)piperidin-4-one with cyclopropylacetylene and subsequent acylation of intermediate 4-(cyclopropylethynyl)piperidin-4-ol. The resulting esters react with β-cyclodextrin to give supramolecular inclusion complexes. The complexation is accompanied by inclusion of the N-ethoxyethyl fragment of one substrate molecule in the inner cavity of one receptor molecule. The structure of 4-acyloxy-4-(cyclopropylethynyl-1-(2-ethoxyethyl)piperidines and their inclusion complexes with cyclodextrin has been studied by NMR spectroscopy.
Synthesis of N-vinylpyrrolidone copolymers with 2-aminoethyl methacrylate as drug carriers
Аннотация
Radical copolymerization of N-vinylpyrrolidone and 2-aminoethyl methacrylate hydrochloride has been studied. Molecular and hydrodynamic characteristics of the resulting copolymers have been determined, and their structure has been confirmed. Conditions favoring conversion of these copolymers into copolymers of N-vinylpyrrolidone with 2-aminoethyl methacrylate of different composition have been elucidated. The suitability of the prepared copolymers as polymeric carriers of monofluoroquinolone ofloxacin has been demonstrated.
Synthesis and study of complexes of copper(II) and mercury(II) with triaryl- and diarylalkylarsine oxides
Аннотация
The interaction of copper(II) and mercury(II) nitrates with triaryl- and diarylalkylarsine oxides has been studied. The reactions in aqueous-alcoholic solution have yielded [M(OAsPh3)4](NO3)2 and [M(OAsRAr2)4](NO3)2 cationic complexes [М = Cu(II) or Hg(II), Ar = Ph, 3-МеC6H4, or 4-МеC6H4, R = Et, Pr, i-Pr, Bu, or i-Bu]. Composition and structure of the products have been elucidated by a set of chemical and physico-chemical methods. IR spectroscopy data have revealed that the bond between the ligand and the metal ion is formed via the oxygen atom of arsenyl group.
Primary decomposition mechanism of cobalt(III) nitrotetrazolatoammine complexes
Аннотация
Results of quantum-chemical simulation of isolated molecules of (5-nitrotetrazolato-N2)pentaaminecobalt(III) perchlorate, cis-bis(5-nitrotetrazolato-N2)tetraamminecobalt(III) perchlorate, and possible products of the primary stage of their decomposition are presented. Molecular properties of the considered molecules and fragments have been determined, and their infrared spectra have been simulated. The major pathway of primary stage of the complexes decomposition is the separation of an ammonia molecule accompanied by rearrangement of the residual fragment. The activation and dissociation energies have been determined.
Influence of platinum metals on spectral and electrochemical characteristics of metallated azole luminophors
Аннотация
Spectral (1H NMR and IR), optical, and voltammetry parameters of Pd(II), Pt(II), Rh(III), and Ir(III) complexes with ethylenediamine and metallated azole luminophors [2-phenylbenzoxazole, 2-phenylbenzothiazole, 2,5-diphenyloxazole, 2-(1,1'-biphenyl)-4-yl]-5-phenyloxazole, and 2-(naphthalene-l-yl)benzothiazole] have been studied. The variation in spectroscopic parameters of the complexes is related to the increase in the efficiency of donor-acceptor interaction of Pt(II) and Ir(III) with the ligands as compared to Pd(II) and Rh(III). The correlation between the energy of the metal-ligand charge transfer bands and the difference between the single-electron oxidation and reduction potentials of the complexes is observed. Quenching of the fluorescence of metallated azoles and phosphorescence of the complexes in the visible region from the metal-modified intraligand excited state are related with the increase in the efficiency of the singlettriplet conversion due to the spin-orbital interaction in platinum metals.
Biomimetic complexes of Cd(II), Mn(II), and Zn(II) with 2-aminomethylbenzimidazole. EGA/MS characterization of the thermally induced decomposition
Аннотация
Cadmium(II), manganese(II), and zinc(II) complexes with 2-aminomethylbenzimidazole have been synthesized following the reported procedures and characterized by mass spectrometry/evolved gas analysis (EGA/MS) to describe their thermally induced decomposition.
Synthesis and biological activity of some amino-4'-substituted phenyl(pyridine)androst-4-en-3-one candidates
Аннотация
A series of substituted androstanopyridine derivatives 2–5 were synthesized using 17-acetyl- 1,7,8,10,11,12,13,15,16,17-decahydro-10,13-dimethyl-2H-cyclopenta[a]-phenanthren-3(6H,9H,14H)-one (progesterone, 1) as a starting material. Reaction of 1a–1d with malononitrile and aldehydes in the presence of ammonium acetate gave the corresponding amino cyanopyridine derivatives 2a–2d. The same compounds 1a–1d reacted with cyanoacetamide and aldehydes in the presence of ammonium acetate to give a mixture of 3a–3d and 4a–4d, that was separated chromatographically. The reaction of compounds 1a–1d with ethyl cyanoacetate and aldehydes led to products 5a–5d. Structures of the newly synthesized compounds were elucidated by physical and spectral methods. The synthesized compounds were tested as 5α-reductase inhibitors and anti-prostate cancer agents.
Evaluation of catalytic activity of two newly prepared functionalized sulfonic acids ionic liquids in the synthesis of carbamatoalkyl naphthols under mild conditions
Аннотация
Catalytic activity of two newly prepared functionalized sulfonic acids ionic liquids, [MPyrrSO3H]Cl (IL1) and [MMorSO3H]Cl (IL2), is studied in one-pot three-component synthesis of carbamatoalkyl naphthols by the reaction of β-naphthol with aromatic aldehydes and methyl or benzyl carbamate. The efficiently catalyzed reaction proceeded under solvent-free conditions. The synthesis was characterized by easy work-up, absence of volatile and hazardous organic solvents, and recyclability of the catalysts.
Synthesis and antimicrobial activity of novel 5-[(1H-indol-3-yl)methylene]thiazolidine-2,4-dione–[1,2,3]triazole hybrids
Аннотация
5-[(1H-Indol-3-yl)methylene]thiazolidine-2,4-dione–[1,2,3]triazole hybrid derivatives were synthesized by click chemistry reaction and screened for antimicrobial activity against Gram positive and Gram negative bacteria and fungal species. All synthesized compounds were characterized by 1H and 13C NMR, IR and MS spectra. Antibacterial study indicated that several products demonstrated high activity and some products were determined to be potentially antifungal active agents.
Synthesis and antimicrobial activity of some novel benzofuran based 1,2,3-triazoles
Аннотация
In the present study, a series of novel {6-[(1H-1,2,3-triazol-4-yl)methoxy]-3-methylbenzofuran-2-yl}(phenyl)methanones (7a–7o) have been synthesized using click chemistry approach. The structures of all newly synthesized compounds were characterized by FT-IR, 1H and 13C NMR, and MASS spectral data. Most of products demonstrated high antimicrobial activity.
Synthesis of novel 2H-chromene-3-carboxylate isoxazole/isoxazoline derivatives via 1,3-dipolar cycloaddition reaction (NOAC)
Аннотация
Synthesis of novel (3-phenylisoxazol-5-yl)methyl-2H-chromene-3-carboxylates (7a–7d) and (3-phenyl-4,5-dihydroisoxazol-5-yl)methyl-2H-chromene-3-carboxylates (8a–8p) by 1,3-dipolar cycloaddition, and nitrile oxide and alkyne cycloaddition (NOAC) is presented. The products are characterised by IR, 1H and 13C NMR, and ESI-MS data.
Letters to the Editor
Electrophilic tropylation of 2-aminopyridine
Аннотация
Electrophilic tropylation of 2-aminopyridine afforded N-(cyclohepta-2,4,6-trien-1-yl)pyridin-2-amine. The product was tested for antibacterial activity against Staphylococcus aureus no. 906 and Candida albicans ATSS 24 433.
Synthesis and structure of N,6-diaryl-4-methyl-2-cyanoimino-1,2,3,6-tetrahydropyrimidine-5-carboxamides
Аннотация
Reactions of acetoacetic acid N-arylamides with aromatic aldehydes and cyanoguanidine have led to the formation of N,6-diaryl-4-methyl-2-cyanoimino-1,2,3,6-tetrahydropyrimidine-5-carboxamides. Structure of the obtained compounds has been confirmed by IR, 1H NMR spectroscopy, and X-ray diffraction data.
Addition of tris(trimethylsilyl) phosphite to N-substituted 4-piperidone
Аннотация
Convenient methods for the synthesis of functionalized phosphonic acids containing piperidine moieties via the reaction of tris(trimethylsilyl) phosphite with N-substituted 4-piperidone derivatives have been developed.