Andrey Yu. Potapov

Objective of the article: This study presents the findings of research on a biomimetic organomineral layer composed of trimethyldihydroquinoline, which was polymerized in the presence of nanocrystalline carbonate-substituted non-stoichiometric hydroxyapatite (n-cHAp).Experimental part: The morphological features of the biomimetic layer were visualized using synchrotron infrared near-field spectroscopy.Conclusions: It has been demonstrated that the biomimetic layer formed on the surface of dental enamel exhibits a morphological structure characterized by a uniformly distributed and densely packed composite film of poly(2,2,4-trimethyl-1,2-dihydroquinoline-6,7-diol) and n-cHAp. The resulting dental coating, which is based on polydihydroquinoline and nanocrystalline hydroxyapatite, possesses a Vickers hardness coefficient comparable to that of healthy enamel

Tetrahydroquinolines are important structural fragments of many biologically active compounds exhibiting antifungal, antitumor, antiviral and neurotropic properties. This paper presents methods for the synthesis of N-substituted tetrahydroquinoline-6-carbaldehydes and a study of the possibility of their olefination using the Wittig and Horner – Wadsworth – Emmons methods. As a result of the interaction of N-alkyl- and N-acylhydroquinolines with the Vilsmeier – Haack complex, N-substituted tetrahydroquinoline-6-carbaldehydes have been obtained in yields of 77–85%. Olefination of the obtained carbaldehydes by the Wittig reaction using triphenylalkylphosphonium salts has made it possible to obtain a number of N-substituted derivatives, including: (E)-3-(2,2,4-trimethyl-1,2,3,4-tetrahydroquinolin-6-yl)acrylonitriles, (E)-1-phenyl-3-(2,2,4- trimethyl-1,2,3,4-tetrahydroquinolin-6-yl)prop-2-en-1-ones, ethyl (E)-3-(N-benzoyl-7-methoxy-2,2,4-trimethyl-1,2,3,4-tetrahydroquinolin-6-yl) acrylate. It has been found that when this interaction is extended to N-benzyl-2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline-6-carbaldehyde and N-benzyl-2,2,4-trimethyl-4-(4-chlorophenyl)-1,2,3,4-tetrahydroquinoline-6-carbaldehyde, difficult-to-separate mixtures are formed, which is explained by the presence of a methylene-active benzyl group in these compounds, which in the presence of sodium methylate can enter into condensation with the aldehyde fragment. The application of the Horner – Wadsworth – Emmons reaction for the olefination of N-methyl- and N-benzyl-1,2,3,4-tetrahydroquinoline-6-carbaldehydes using dimethyl (cyanomethyl) phosphonate has made it possible to synthesize (E)-3-(Nmethyl-2,2,4-trimethyl-1,2,3,4-tetrahydroquinolin-6-yl) acrylonitrile, (E)-3-(N-benzyl-2,2,4-trimethyl-1,2,3,4-tetrahydroquinolin-6-yl) acrylonitrile and (E)-3-(-N-benzyl-2,2,4-trimethyl-4-(4-chlorophenyl)-1,2,3,4-tetrahydroquinolin-6-yl) acrylonitrile with yields of 83–89%. Analysis of the ¹H NMR spectra has showed that all the synthesized olefination products are in the form of E-isomers. The obtained results demonstrate the potential of using the developed methods for the synthesis of new tetrahydroquinoline derivatives.

The paper proposes a strategy for the accelerated deposition of biomimetic organomineral layers on the surface of dental enamel, utilizing di/tetrahydroquinolinediol (hydroxyquinoline) polymerized in the presence of nanocrystalline hydroxyapatite (nano-cHAp). The mechanisms underlying the formation of dental coatings were elucidated through a combination of structural, microstructural, and spectroscopic analytical methods, including synchrotron infrared nanoimaging. Additionally, the antimicrobial effects of these coatings were investigated. It has been demonstrated that the deposition of an organomineral layer, based on polymerized dihydroxyquinoline, on the surface of natural enamel leads to the agglomeration and orientation of hydroxyapatite nanocrystals within the coating. This process enables the layer to replicate the mechanical properties of natural enamel, resulting in a microhardness value that closely resembles that of natural enamel. Using synchrotron s-SNOM, it has been established that the biomimetic organomineral layer possesses the morphological structure of a poly(2,2,4-trimethyl-1,2-dihydroquinoline-6,7-diol (TMDHQ))/nano-cHAp composite film, which is homogeneously distributed and tightly packed on the enamel surface. Furthermore, it has been demonstrated that the dental coating formed from polydihydroxyquinoline and nanocrystalline hydroxyapatite exhibits inhibitory activity against colonies of Streptococcus spp. The developed technology for the formation of dental biomimetic layers, which exhibit simultaneous antibacterial and mineralizing effects, holds significant potential for future clinical applications.

Among the fused azaheterocycles, quinolines have long attracted the attention of chemists. First of all, this is due to their wide range of practically useful properties. Quinolines and their derivatives exhibit a wide range of biological activities, including antimalarial, anticancer, antiviral, antifungal and anti-inflammatory activities. These compounds are also used as fluorescent probes, luminescent labels, and in dye production. In the course of this work, a series of pyridocoumarin systems have been obtained, which have been tested as inhibitors of blood clotting factors Xa and XIa. The method for the synthesis of the proposed compounds involves the condensation of 7-hydroxy-2,2,4-trimethyl-1,2- dihydroquinolines and 7-hydroxy-2,2,4-trimethyl-1,2,3,4-tetrahydroquinolines with malononitrile and aryl(hetaryl)aldehydes. It has been found that as a result of this interaction, new 4H-pyrano[3,2-g]quinoline-3-carbonitriles are formed. In addition, new derivatives of 7-hydroxy-2,2,4- trimethyl-1,2,3,4-tetrahydroquinoline containing an aryl fragment in the 4-position have been obtained, which have been also used as starting compounds for the annelation reaction of the pyran ring. The pyridocoumarin systems obtained in the study have showed promising inhibitory activity against these coagulation factors, making them promising candidates for further study as potential anticoagulant drugs.

The study was made during 2017–2020 in Central Black Earth (as basis), some Russian regions and in Kazakhstan. The main indicators were “yield”, “sugar content”, “sugar yield”, which were determined by traditional methods. То improve sowing properties of male sterile (MS) component, seeds were treated with synthesized organic compounds: 6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline and 2-benzylamino-4-methylpyrimidine-5-carboxylic acid. An increase of seed germinative energy, seed germination, seedling length, and mass of 100 seedlings in the experiment as compared to the cont rol (%) were calculated. A positive effect from seed treatment on their sowing qualities and a stimulation of growth indicators was revealed in all variants of using the dihydroquinoline and the pyrimidine-carboxylic acid. A high level of monogermity (98–100 %) was noted in obtained hybrids. Studied hybrids show a higher level of main indicators: “yield”, “sugar content”, “sugar yield” compared to the standard. The treatment of uncoated sugar beet seeds with the pyrimidine-carboxylic acid provides an increase in seed germination energy by 29–55 %, seed germination by 25–53 %, average seedling length by 43–70 %, weight of 100 seedlings by 61–80 % compared to the control. Studied substances can be accepted as growth stimulants for sugar beet in laboratory and in field. Using CMS allows to create heterotic hybrids with the complex of economically valuable properties quicker compared to the traditional selection. This research provides obtaining hybrids on a sterile basis and study their useful properties. The results presented in the paper can be applied in the production process of sugar beet hybrids.

A convenient approach to the synthesis of new 2-R-6H-benzopyrano[4,3-е][1,2,4]triazolo[5,1-c][1,2,4]triazin-6-ones and 2-R-[1,2,4]triazolo[5',1':3,4][1,2,4]triazino[6,5-c]quinolin-6(7H)-ones, based on the condensation of 3-R-1H-1,2,4-triazolo-5-diazonium salts with 2H-1-benzopyran-2,4(3H)-dione and quinoline-2,4(1H,3H)-dione, is developed.

The creation of buffer (hybrid) layers that provide improved adhesion to two heterogeneous materials is a promising and high-priority research area in the field of dental materials science. In our work, using FTIR and Raman microspectroscopy at the submicron level in a system of dental composites/intact dental enamel, we assessed the molecular features of formation and chemically visualized the hybrid interface formed on the basis of a nature-like adhesive, polydopamine (PDA). It is shown that a homogeneous bioinspired PDA–hybrid interface with an increased content of O-Ca-O bonds can be created using traditional methods of dental tissue pretreatment (diamond micro drilling, acid etching), as well as the subsequent alkalinization procedure and the developed synthesis technology. The development of the proposed technology for accelerated deposition of PDA–hybrid layers, as well as the creation of self-assembled biomimetic nanocomposites with antibacterial properties, may in the future find clinical application for minimally invasive dental restoration procedures.

In our work, we studied thin nickel films deposited by electroless plating for use as a barrier and seed layer in the through-silicon vias (TSV) technology. El-Ni coatings were deposited on a copper substrate from the original electrolyte and with the use of various concentrations of organic additives in the composition of the electrolyte. The surface morphology, crystal state, and phase composition of the deposited coatings were studied by SEM, AFM, and XRD methods. The El-Ni coating deposited without the use of an organic additive has an irregular topography with rare phenocrysts of globular formations of hemispherical shape and a root mean square roughness value of 13.62 nm. The phosphorus concentration in the coating is 9.78 wt.%. According to the results of the X-ray diffraction studies of El-Ni, the coating deposited without the use of an organic additive has a nanocrystalline structure with an average nickel crystallite size of 2.76 nm. The influence of the organic additive is seen in the smoothening of the samples surface. The root mean square roughness values of the El-Ni sample coatings vary within 2.09–2.70 nm. According to microanalysis data the phosphorus concentration in the developed coatings is ~4.7–6.2 wt.%. The study of the crystalline state of the deposited coatings by X-ray diffraction made it possible to detect two arrays of nanocrystallites in their structure, with average sizes of 4.8–10.3 nm and 1.3–2.6 nm.

Copper is widely used as a material for technical solutions in microelectronics, as well as for the manufacture of various heat exchange equipment used in aggressive environments. Corrosion inhibitors are used for the reduction of the corrosive activity of the environment. This article presents the results of a study of the anticorrosion activity of a number of derivatives of the class 3-alkyl- and 3-hydroxyalkyl-5-amino-1H-1,2,4-triazole with respect to copper corrosion in chloride-containing environment. Over the course of the study, 3-alkyl- and 3-hydroxyalkyl-5-amino-1H-1,2,4-triazoles with different lengths of the alkyl substituent were synthesized. The structure of these compounds was confirmed using NMR spectroscopy and HPLC/MS analysis. Based on the results of electrochemical and direct corrosion tests, regularities were established for the inhibitory activity of the obtained compounds in acidic (1% HCl solution) and neutral (borate buffer solution, pH = 7.4) chloride-containing media. In in a neutral media, the greatest protective effect was obtained for 3-propyl-5-amino-1H-1,2,4-triazole I, which has the shortest alkyl radical without modification by an OH group. As the concentration increased in the range from 0.01 to 10.0 mmol/L, the inhibitory activity increased. With an increase in the length of the alkyl radical and/or the introduction of an OH group, a decrease or absence of a protective effect was observed. At the same time, in an acidic medium, the introduction of a hydroxyl group into the alkyl substituent of 5-amino-1H-1,2,4-triazole increased anti-corrosion efficiency only with sufficient length of the carbon chain. The highest protection degree was obtained for 17-(5-amino-1H-1,2,4-triazol-3-yl)heptadecan-7-ol IV at a concentration of 10.0 mmol/l and it reached a value of 97%.