Vol 94, No 2 (2024)

The synthesis of disecondary aromatic diols (the main precursors for divinyl aromatic monomers) was carried out. The optimal conditions for the preparation of these diols by selective catalytic hydrogenation of aromatic diketones in the presence of Raney nickel and by reduction of these diketones by sodium borohydride were established. It was demonstrated that sodium borohydride reduction afforded the pure diols under mild and relatively safe conditions (in the systems of CHCl₃–PEG400–H₂O, at room temperature and atmospheric pressure).

Heterocyclization of 3-[(alkylsulfanyl)methyl]pentane-2,4-diols with formaldehyde or propionaldehyde in boiling benzene in the presence of hydrochloric acid afforded new 5-[(alkylsulfanyl)methyl]-4,6-dimethyl-1,3-dioxanes. 1,3-Dioxanes are formed as a mixture of 4,6-cis- and 4,6-trans-isomers at a ratio of 1:0.3–0.9. In both isomers, the preferred chair conformation is realized. In the 4,6-cis-isomers of all 1,3-dioxanes, the methyl groups occupy a diequatorial position, and the alkylsulfanylmethyl substituent is in an axial orientation. In the 4,6-cis-isomer of 5-[(pentylsulfanyl)methyl]-2-ethyl-1,3-dioxane, the ethyl group is oriented equatorially. The 4,6-trans-isomers of 5-[(alkylsulfanyl)methyl]-1,3-dioxanes are characterized by a rapid conformational inversion chair–chair.

A new transformation of 3,6-diphenyl-1,2,4,5-tetrazine was discovered during the solvent-free reaction with 2-amino-4-aryloxazoles, leading to the formation of 2,5,7-triaryl[1,2,4]triazolo[1,5-a]pyrimidines. Stucture of products was also confirmed by single crystal X-ray diffraction data. A possible mechanism for this reaction was proposed.

New catalysts for the Prins condensation of renewable monoterpene compounds with aldehydes were considered. Effective catalytic systems were functionalized zeolites, oxides, clays, halloysite and carbon nanotubes, organometallic structures and heteropolyacids, which make it possible to obtain target products with high selectivity. A number of compounds synthesized using such systems are used in perfumery, have high pharmaceutical potential and are platform molecules for further synthesis.

We represent the Gibbs energies of cryptand[2.2.2] transfer from water to different composition water–dimethyl sulfoxide solvent. The Gibbs energies were determined by interphase distribution of cryptand[2.2.2] between two immiscible solvents. We conclude, that when the dimethyl sulfoxide concentration increases, the cryptand[2.2.2] solvation is weakening.

An inclusion complex of gadolinium(III) with L-tryptophan (Trp) and β-cyclodextrin (β-CD) with the composition Gd(Trp)₃Cl₃∙3β-CD∙nH₂O was synthesized. It was established that the complex is formed due to the entry of the aromatic part of the L-Trp molecule into the β-CD cavity, and the Gd³⁺ ions are located in the outer sphere.

This study presents the results of the synthesis and examination of indium-substituted barium hexaferrite samples with the formula BaFe_12–xIn_xO₁₉. The ferrites were obtained via a solid state synthesis method. The substitution level of indium, represented by x(In), was varied from 0 to 1 in 0.25 increments. The stoichiometric formulas of the compounds were calculated using the EDS data. The powder X-ray diffraction analysis indicated that all samples form a single crystalline phase with the M-type hexaferrite structure. Parameters of the crystal unit cell were calculated from powder diffraction data. An expansion of the crystal lattice parameters was observed as iron was substituted with indium, from x = 0 to x = 0.84. The Curie temperatures of the synthesized ferrites were determined using differential scanning calorimetry (DSC) method. It is established that the Curie temperature decreases from 452 to 292°C with In content growth from x = 0 to x = 0.84 in the BaFe_12–xIn_xO₁₉.

The conditions for the synthesis of sparingly soluble salts of lead, cadmium, mercury(II), copper(II) and iron(II, III) with anions of some organic acids H_mL were given. Based on their solubility data (ionic strength I = 0.1), the solubility constants K_S were calculated; based on the [Mⁿ⁺]/MPC_M ratio, conclusions were drawn about the applicability of low-toxic organic ligands as precipitators (antidotes) of toxic metal ions. It was shown that deactivation is also possible during the redox reaction of mercury(II), copper(II) with ascorbic acid. According to adsorption data on activated carbon, a number of ions were established to reduce sorption (deactivation ability): Pb²⁺ (96.6%), Fe³⁺ (95.4%), Hg²⁺ (80.6%), Cd²⁺ (42.4%). Adsorption data complemented the results of reagent methods for studying the detoxification of metal ions.