Vol 89, No 8 (2019)

It has been found that nickel nanoparticles on NaX zeolite, γ-alumina, activated carbon, or magnesium oxide support catalyze the reduction of nitrobenzene and its homologs affording aniline and its derivatives in high yield. The effect of the substrate on the process in a continuous reactor at atmospheric hydrogen pressure has been investigated. The use of activated carbon or magnesium oxide as a carrier allows proceeding of the reaction at 80–100°C.

Decomposition of benzoyl peroxide in the presence of ferrocene has been shown to proceed simultaneously via several pathways—thermal decomposition, the decomposition catalyzed by iron ions, and the reaction with ferrocene with the formation of ferrocenium radical-cation.

Reaction of 2-aminopyridine with allyl bromide, methallyl chloride, 2-bromoallyl bromide, and propargyl bromide in acetone furnished 2-amino-1-allyl-, methallyl-, (2-bromoallyl)-, and propargylpyridinium halides. 2-Amino-1-allyl(methallyl)pyridinium halides reacted with bromine and iodine to form 2-halomethyl-2,3-dihydro-1H-imidazo[1,2-a]pyridinium systems. 2-Amino-1-(2-bromoallyl)pyridinium bromide underwent heterocyclization under the action of bromine, and did not react with iodine. 2-Amino-1-propargylpyridinium bromide reacted with bromine and iodine to form 2-halomemylene-2,3-dihydro-1H-imidazo[1,2-a]pyridinium systems.

The method of synthesis of fused thiopyridines via S-alkylation of the corresponding pyridine thiones with propargyl bromide has been elaborated. Fused enol tautomers have been obtained via the reaction of the prepared thiopropargyl pyridine compounds with acetylacetone in the presence of mercury(II) acetate followed by the reduction of intermediate organomercury compounds with alkali solution of sodium borohydride. Neurotropic activity of the synthesized compounds has been studied, and compounds with pronounced anticonvulsant activity have been identified.

The nitration, bromination, diazo coupling, sulfonation, and alkylation of the aromatic ring of a series of 2-phosphoryl-substituted phenols have been studied for the first time. 2,6-Diphosphorylphenols have been obtained for the first time via 1,3-phosphorotropic phosphate-phosphonate rearrangement. The alkylation of 2-(diphenylphosphoryl)phenol at the hydroxy group with 2-bromo- and 2-chloroethanols has been studied under conventional heating and microwave irradiation conditions.

Based on 1,3,3,5,5-penta[1-(2,2-dimethyl-1,3-dioxolan-4-yl)methoxy]-1-chlorocyclotriphosphazene, a series of hybrid compounds was obtained by two-step synthesis. In the molecules of the compounds obtained, hydrophobic organic residues are attached to the cyclotriphosphazene nucleus via a linker. A dialkyl substituted 1,2,3-triazole synthesized by click-chemistry methodology from acetylenic cyclotriphosphazene derivatives and organic azides in the presence of Cu(I) can be used as a linker connecting pentadioxolane-substituted phosphazene core. The reaction proceeds regioselectively with the formation of 1,4-disubstituted 1,2,3-triazoles only.

The interaction of hydrated uranium(VI) oxide UO₃·2.25H₂O (schoepite) with an aqueous solution of rubidium hydroxide in an autoclave at 100°C has yielded rubidium uranate Rb₂(UO₂)₆O₃(OH)₈·6H₂O. Composition and structure of the obtained compound have been determined by chemical analysis, IR spectroscopy, X-ray diffraction, and differential thermal analysis. The processes of its dehydration and thermal decomposition have been studied.

A new silver(I) cyclohexamethylene dithiocarbamate has been isolated in the form of a hexanuclear solvated cluster [Ag₆{S₂CN(CH₂)₆}₆]·2CH₂Cl₂. Structure of the obtained compound has been elucidated by IR spectroscopy, X-ray diffraction analysis, and simultaneous thermal analysis methods. Each of the dithiocarbamate ligands performs a μ₃-bridging function, asymmetrically linking three silver atoms. The molecules of the complex are additionally stabilized by argentophilic Ag-Ag bonds (3.0204 Å) formed by each of the silver atoms with two nearest neighbors. The multistage thermal decomposition process of the resulting complex includes desolvation and thermolysis of a six-nuclear cluster with the formation of Ag₂S and elemental silver as intermediate and final products, respectively.

Significant extraction degree of calcium and yttrium chlorides with solutions of the corresponding tetraphenylborates in tributyl phosphate has been revealed, due to the formation of mixed complex compounds in the organic phase. It has been shown that lithium, calcium, and yttrium tetraphenylborates are significantly dissociated in the organic phase. The process has been studied by conductometry. Based on the obtained data, it has been suggested that the formation of mixed halide complexes is owing to the high energy of the solvated ion pairs [CaL_n]²⁺(A⁻)₂ and [YL_m]³⁺(A⁻)₃ in organic solutions, which is significantly decreased upon the exchange of large tetraphenylborate anions with small chloride anions, possibly with the formation of solvated ion pairs with a lower charge of the cationic part of the complex [CaL_n−1Cl]⁺A⁻ or [YL_m−2Cl₂]⁺A⁻

Chlorine-substituted perovskite Ba_3.95In₂Zr₂O_10.9Cl_0.1 was synthesized for the first time, and its single-phase nature was confirmed by X-ray diffraction method. The resultant perovskite has a cubic structure and is a proton conductor at T < 650°C and p(H₂O) = 2×10⁻² atm. Doping with chlorine was shown to increase the oxygen-ion and proton conductivities.

New piperidinone incorporating pyrimidine, triazine, diazipine, oxatriazine, and thiazole derivatives have been synthesized starting with tetramethylpipridin-4-one. Structures of the newly synthesized compounds are characterized on the basis of spectroscopic and analytical data. The anticancer activity of the prepared compounds has been studied in vitro against HCT-116 and MCF-7 human cancer cells using the MTT assay. A number of compounds demonstrates potent activity towards both cell lines with IC₅₀ values comparable with doxorubicin.

The current study is devoted to the synthesis of Schiff base ligand, HL, by condensation of 5-aminosalicylic acid with o-vanillin, followed by preparing its Cu(II), Co(II), Mn(II), and Zn(II) complexes, and their characterization. The Schiff base behaves as a bidentate ligand which forms tetrahedral complexes with Cu(II) and Zn(II), unlike Co(II) and Mn(II) that give octahedral complexes. The Schiff base ligand and its complexes with Cu²⁺, Co²⁺, Mn²⁺, and Zn²⁺ exhibit considerable antibacterial activity against some drug resistant reference strains and local isolates of S. aureus, E. Coli, P. aersginosa. Overall, the metal complexes exhibit more potent antibacterial activity than the ligand HL alone.

Mononuclear Au(III) Schiff base complexes are synthesized by the reaction of 4-aminoantipyrine with hydrazine. The chemical structures of new Schiff bases and their Au(III) complexes are elucidated from their conductance, XRD, and spectroscopic (IR, UV-Vis, ¹H, and ¹³C NMR) data. Au(III) Ion is coordinated with the synthesized Schiff bases via four nitrogen atoms of the antipyrine and azomethine groups. Au(III) Complexes are electrolytes with three uncoordinated Cl⁻ ions, and have a square planar geometry. Their morphology is characterized by SEM and TEM methods. Cytotoxic effect of the complexes is tested against human breast cancer (MCF-7) and hepatocellular carcinoma (HepG-2) cell lines.

A series of novel 1,2-isoxazole-pyridobenzimidazole is synthesized. Structures of the products are supported by ¹H and ¹³C NMR, and mass spectra. All compounds have been tested for their anticancer activity towards four human cancer cell lines including MCF-7 (breast cancer), A549 (lung cancer), Colon-205 (colon cancer), and A2780 (ovarian cancer). Etoposide was used as a standard drug. The determined IC₅₀ values range from 0.01±0.003 to 23.7±3.72 µM. Among all compounds, six products exhibit the most significant activities.

A synthetic approach to combining pharmacophore ligands with an aminoadamantyl-containing spacer based on a copper-catalyzed alkyne-azide 1,3-dipolar cycloaddition of N,N-di(prop-2-yne-1-yl)adamantan-1-amines and azido-containing carbazole, tetrahydrocarbazole, phenothiazine and adamantan-2-amine derivatives was proposed.

The interaction of the fullerene C₆₀-L-arginine adduct with human serum albumin (HSA) has been studied by means of isothermal calorimetric titration at 298.15 K. The formation of the C₆₀-Arg-HSA complex with a stoichiometric ratio of 1 : 0.7 has been revealed.

The fourth author of the article should read S. A. Ahmada^a.