Volume 87, Nº 5 (2017)

Products of the zirconium powder reaction with amorphous boron in a Na₂B₄O₇ ionic melt at 650–850°C and those of the ZrCl₄ reaction with NaBH₄ at 300–725°C have been studied by means of X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry, and elemental analysis. At temperature ≥750°C, single-phase ZrB₂ with the particle size of 60–80 nm is formed in a Na₂B₄O₇ ionic melt, whereas the ZrB₂ powder obtained via the reaction of ZrCl₄ with NaBH₄ at temperature ≥575°C consists of particles differing in the shape, some of which are close to spherical with diameter of 10–35 nm.

Comparison of experimental values of gas-phase formation enthalpy of cyclophanes with the results of semiempirical quantum-chemical simulation has revealed good linear correlation with the PM-3 data. Using the derived equation, formation enthalpies of 30 cyclophanes have been predicted.

Indirect cathodic amination of benzene with hydroxylamine in the presence of Ti(IV)/Ti(III) mediator system in aqueous media containing 4–11 mol/L H₂SO₄ and 13–5.5 mol/L AcOH has been studied. Aniline, diphenyl, and isomeric phenylenediamines are the electrolysis products at 25–60°C. The increase in temperature favors the formation of the monoamino compound. Aniline yield with respect to hydroxylamine at complete conversion of the latter has reached 78.7%, mass fraction of aniline being 97.1%.

Ionic liquids based on 1-alkyloxycarbonylmethyl-3-methylpyridinium and Cl^– and PF₆^– anions have been synthesized. The conductivity of their solutions in acetonitrile and the thermal stability over 25–500°C in air have been determined.

4-Hydroxy-6H-1,3-oxazin-6-ones containing a 3-vinylchromone fragment in the 2-position were synthesized. The direction of their reactions with hydrazine hydrate was found to depend on the solvent nature. The reaction in protic solvents (methanol, acetic acid) resulted in recyclization of both oxazine ring to 1,2,4-triazole and pyranone ring to pyrazole. Aprotic acetonitrile favored attack of hydrazine exclusively on the oxazine ring, while the 3-vinylchromone fragment remained intact.

Bis(1,5,3-dithiazepanes) have been synthesized via cyclocondensation of aliphatic α,ω-diamines and hydrazine with formaldehyde and ethane-1,2-dithiol. Palladium(II) sorption with bis(1,5,3-dithiazepanes) from nitric acid solutions has been studied via a static method. Bis(1,5,3-dithiazepanes) efficiently extract palladium(II) from 0.1−4 mol/L nitric acid solutions at room temperature.

Aminomethylation and cyanoethylation reactions of 5-(4-alkoxybenzyl)-4-methyl(phenyl, allyl)-4H-1,2,4-triazole-3-thiols have been investigated. According to NMR spectroscopy data, the reactions occur at the nitrogen atom Ν². The effect of the synthesized compounds on cancer DNA methylation has been evaluated.

Novel derivatives of 3,3-dichloroprop-2-enenitrile containing methylurea or phenylurea fragments have been synthesized. The obtained N-(2,2-dichloro-1-cyanoethenyl)-N′-methyl(phenyl)ureas undergo intramolecular cyclization in the presence of triethylamine to form 4-(dichloromethylidene)-5-imino-1-methyl (phenyl)imidazolidin-2-ones. Reactions of N-(2,2-dichloro-1-cyanoethenyl)-N′-methylurea with aliphatic amines have afforded 4-(alkylamino)-4-(dichloromethyl)-5-imino-1-methylimidazolidin-2-ones.

The review describes the modern methods of synthesis and chemical modification of carboxylcontaining phosphazenes. The possibility of their use in the synthesis of polyamides, epoxy resins, star-shaped and structured polymers, hydrogels, and metal complexes is considered. Carboxyl-containing phosphazenes and their derivatives are of great interest for medicine, electronics, photonics, and design of multipurpose hightech composite materials, offering wide opportunities for further research and application.

New dinuclear copper(I) complexes with bridging bis-diimine ligands were synthesized on the basis of benzimidazole derivatives. The obtained complexes showed photo- and electroluminescent properties. Copper-containing emitters exhibited yellow, orange, and yellow–green electroluminescence with a maximum brightness of 1166 cd/m².

The interaction of ferrocene with styrene and methyl methacrylate in media of different polarity (hexane, tetrachloromethane, and ethanol) has been studied by means of UV spectroscopy using the isomolar series method. For both monomers, intermediate complexes are formed, the medium polarity significantly affecting the complexes formation. Ferrocene acts differently in the interaction with styrene (being the electron acceptor) and methyl methacrylate (being the electron donor). It has been discovered that only in the case of ethanol a charge-transfer complex between ferrocene and styrene is formed. Possible structures of the intermediate complexes have been suggested.

The effect of ferrocene on the synthesis of graft poly(dimethylsiloxanes) by radical copolymerization of a polysiloxane containing terminal trivinylsiloxy groups with styrene. The backbone in the synthesized graft copolymers is formed by a linear poly(dimethylsiloxane) with a part of its vinyl groups involved in grafting polystyrene chains. The products were studied by gel permeation chromatography, ¹Н NMR spectroscopy, and optical microscopy.

Four novel N-methylpiperidin-4-one derivatives were synthesized and characterized by IR, ¹H NMR, HRMS, and single crystal X-ray crystallography. The anticancer activity of these compounds was studied on five human endometrial cancer cell lines (RL-95-2, HEC-1A, HEC-1B, AN3CN and HECCL-1). Efficient antitumor effect was found for the 3,5-difluorophenyl- and 3-cyanophenyl-substituted derivatives.

A wide variety of 2-amino-4H-chromene derivatives with diverse substituents on the 4H-chromene ring were efficiently prepared via one-pot three-component reaction of an aromatic aldehyde and malononitrile with 2-hydroxynaphthalene-1,4-dione, ethyl acetoacetate, or naphthols in the presence of triethanolamine as a new organocatalyst under solvent-free conditions. The procedure is transition metal-free and environmentally friendly approach to various 2-amino-4H-chromene derivatives. Its advantages include short reaction time, high yields, low cost, and straightforward work-up. Triethanolamine is an efficient reusable catalyst. 2-Amino-4H-benzo[g]chromenes (ABgC) were applied as novel components of electro synthesis of silver nanoparticles.

In the scope of a broader study focused on glutamate receptors regulators, we have been engaged in synthesis, analysis and pharmacological characterization of rigid analogues of glutamic acid. These compounds exhibited the bioisosteric replacement of the distal carboxylic group with the sulfonic one. Besides the sophisticated synthetic approach, we targeted preparation of a series of cyclopropyl-containing sulfonyl amino acids and development of a chromatographic enantioselective method suitable for distinguishing and quantifying the resulting isomers. Due to chelating ability, the chiral ligand-exchange chromatography (CLEC) was used for diastereo- and enantioseparation of the synthesized compounds. The CLEC-based enantioseparation was achieved by using a chiral mobile phase (CMP) system with N,N-dimethyl-(S)-phenylalanine [(S)-DMP] as the chiral selector. Only one of the investigated enantiomeric pairs was undiscriminated with the employed CLEC–CMP system which, very importantly, produced the simultaneous diastereo- and enantioseparation of two compounds of the series. Furthermore, the large α and RS values computed for three enantiomer pairs could be a good basis for a successful scale-up to a semi-preparative level.

Five new cefradine (Cef) drug complexes were synthesized by 1 : 1 chemical reactions with Ca(II), Zn(II), Fe(III), Au(III), and Pd(II) ions in alkaline methanol/distilled water media. The general formula of Cef complexes can be presented as [M(Cef)Cl_n]·Cl_y·xH₂O, where (M = Ca^II, Zn^II, Fe^III, Au^III, or Pd^II; n = 1, 2; y = 0,1; and x = 0, 3, 7, 14). Structures and physicochemical characteristics of complexes are studied by elemental analyses, IR, Raman and UV-Vis spectra, effective magnetic moments, X-ray powder diffraction (XRD), molar conductivity, SEM and TEM methods. Cef drug acts as a tridentate ligand toward the metal ions via oxygen atoms of the carbonyl β-lactam and carboxylate groups and nitrogen of the amino group. The effective magnetic moment of the paramagnetic Fe(III) complex in the solid state was assigned to the octahedral geometric structure. Antibacterial activity of the complexes were tested against some kinds of bacteria and fungi strains. Cytotoxicity of Au(III) complex was tested on human colon carcinoma (HCT-116) and hepatocellular carcinoma cells (HepG-2) using the MTT viability test. The results demonstrated the significant cytotoxic effect compared to the other complexes.

The reaction of iron(III) ions with dispersed titanium in aqueous solution has been studied. The Fe–Ti species thus obtained have been found to be a combination of core–shell microparticles with the titanium core coated with ultramicro- and nanosized α-Fe nuclei and an ultrathin outer iron(III) oxide layer with a developed surface.

The addition of alkanethiols, benzenethiol, and hetarenethiols to phosphorylated quinomethanes afforded P,S- and N,P,S-containing polyfunctional organic compounds as potential bactericidal agents.