Fliur Macaev

The importance of the research lies in the fact that on the basis of extreme environmental conditions, the diversity of phytopathogenic fungal and bacterial strains increases in various aspects - morphology, virulence, resistance to various factors, including the action of chemical preparations, thus increasingly requiring the development of effective preparations against these phytopathogenic agents. The purpose of the research was to establish the antimicrobial effect of new vinyl-triazole derivatives (DVT) on some isolates of the Fusarium semitectum fungus and phytopathogenic bacteria under in vitro conditions. The objectives were to investigate the action of the new compounds on the mentioned phytopathogenic agents, which led to the identification of DVT: EPS-860, EPS-165, EPS-297, with complex antimicrobial activity, thus providing opportunities for their use in plant protection measures against the fungus F. semitectum and the bacteria Erwinia carotovora, Xanthomonas campestris.

A p-phenylenediamine-catechol-based oligomer was synthesized via oxidative polycondensation in an acidic medium under ultrasonic irradiation, employing potassium persulfate as the oxidant to obtain an oligomeric material. The resulting material was characterized by Fourier-transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, thermogravimetric analysis (TGA), nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction, and electron spin resonance (ESR) spectroscopy. FT-IR and NMR analyses confirm that the reaction conditions (with and without surfactant, in presence of ethanol) significantly affect the composition of the resulting materials. It was established that, depending on the reaction conditions, the formation of a trimer composed of two para-phenylenediamine units and one catechol moiety, as well as the formation of poly-1,2-dihydroxybenzene, occurs in different ratios. No products of the individual polycondensation of p-phenylenediamine were detected. UV-Vis spectroscopy indicates wide-band-gap semiconducting behavior, with an optical band gap of approximately 4.7 eV estimated from the Tauc plot analysis. TGA shows the oligomer is stable up to ~270°C. SEM revealed an irregular, predominantly flake-like fragmented surface morphology without well-defined individual particles. ESR confirmed unpaired electrons within the oligomer structure. Temperature-dependent conductivity measurements revealed an unusual conductivity trend, where conductivity slightly increased with decreasing temperature within the investigated range. At room temperature, the measured conductivity is 1.06 × 10-7 S/cm.

The importance of the research lies in the fact that against the background of extreme environmental conditions, the diversity of phytopathogenic fungal strains increases in various aspects - morphology, virulence, resistance to various factors, including the action of chemical preparations, thus increasingly demanding the development of effective preparations against phytopathogenic agents. The purpose of the research was to establish in vitro conditions the antifungal effect of new vinyl-triazole derivatives (DVT) against one of the most widespread fungi - Nigrospora maydis. The objectives were to establish the specifics of the effectiveness of the mentioned preparations depending on the structure and concentration. It was established that EPS-165, MF-EPS-297, MF-EPS-860 exhibit pronounced antifungal activity in the concentration range of 0.0025 ... 0.02%, thus there are opportunities for their use in plant protection measures against the fungus Nigrospora maydis.

This paper describes a method for the synthesis of biologically active compounds based on 1(alkyl/aryl)-2-(1H-1,2,4-triazol-1-yl)ethanones with aromatic aldehydes under Knövenagel reaction conditions. The studies are based on the possibility of selectively using 1-(alkyl/aryl)-2- (1H-1,2,4-triazol1-yl)ethanone derivatives, a distinctive structural feature of which is the presence of an activated methylene group; when this group reacts with aldehydes, it yields N-vinyl-triazoles in which the nitrogen atom is bonded to an sp²-hybridized carbon atom of a substituted olefin. In reactions with salicylic aldehyde derivatives, these compounds form hemiketals in which the carbon atom of the carbonyl group becomes asymmetric. An evaluation of the "structure-bioactivity" relationship was conducted for a series of synthesized alkyl/aryl-substituted N-vinyl triazoles. The resulting compounds exhibit biological activity and show promise for application in medicine and agriculture as antimicrobial agents and plant growth regulators.

The paper addresses the synthesis and evaluation of hydrophosphoranes derived from (+)-3-carene as chiral ligands in asymmetric catalysis. Through oxidative transformations and subsequent reactions, spiro-hydrophosphorane-type compounds were obtained and characterized by spectroscopic methods (IR, NMR). These compounds were employed in palladium-based catalytic systems for allylic sulfonylation and amination reactions. The results indicate a limited influence of complexation time on the yield of racemic products, while highlighting the occurrence of asymmetric induction (up to 37% ee) under optimal conditions. Furthermore, the nature of the amine and the solvent significantly affects conversion and selectivity. The study demonstrates the potential of hydrophosphoranes as efficient ligands in asymmetric catalysis, providing perspectives for the development of high-performance catalytic systems.

This study explores the synthesis of lawsone-derived aminonaphthoquinones with potential anticancer activity via the one-pot Mannich reaction. A series of nine lawsone Mannich bases, five of them being novel, were obtained from 2-hydroxy-1,4-naphthoquinone, butylamine/benzylamine, and various benzaldehydes under mild conditions in ethanol at room temperature, with convenient isolation by precipitation. The synthesized compounds were characterized by melting point, elemental analysis, and FTIR spectroscopy. Their cytotoxicity toward the human malignant melanoma cell line A375 was evaluated using MTT and LDH endpoint assays. The compounds showed concentration-dependent biological effects, with increased mitochondrial activity at lower doses and loss of cell viability at higher concentrations. These results highlight the value of the Mannich reaction as a simple route to diverse lawsone-derived bioactive scaffolds, and support further investigation of lawsone Mannich bases.

This work is focused on the synthesis of 1,2,3-triazole derivatives based on the artemisinin scaffold, employed as a valuable structural motif in the design of biologically active compounds. The coppercatalyzed azide-alkyne cycloaddition reaction was investigated using carane and steroidal azides. It was demonstrated that the nature of the azide and the reaction conditions significantly influence the yield and course of the process, including secondary hydrolysis and rearrangement pathways. As a result, hybrid compounds incorporating both artemisinin and 1,2,3-triazole fragments were obtained. The structures of the products were confirmed by modern spectroscopic methods (IR, ¹H and ¹³C NMR, HSQC, HMBC, NOESY) and mass spectrometry.

"Click chemistry" has become a popular method for the rapid synthesis of pharmaceutical compounds, with azides and alkynes significantly affecting the reaction rate and regioselectivity in [3+2] cycloadditions. (+)-3-Carene derivatives with chiral centers were converted into azidoalcohols and subsequently into heterorganic compounds through [3+2] cycloaddition, with the effects of substituents and reaction conditions studied. Hybrid molecules containing 2-carene fragments and nitrogen-containing heterocycles were synthesized, achieving yields ranging from 45-74%. Cytotoxic activity was evaluated across multiple cell lines; compounds 8, 9, 14, and 15 were non-toxic, while compounds 3, 4, and heterocompounds 5-7, 10-14, and 16 showed moderate activity. Product 17 exhibited the highest cytotoxic activity, with IC₅₀ values below 10 μM across all cell lines.

The oxidative polycondensation method was used to synthesize an oligomer based on methaphenylenediamine and resorcinol, in an acidic medium, utilizing potassium persulfate as an oxidizing agent. The goal of this study was to obtain multifunctional materials with enhanced physicochemical features and electroactive qualities. FTIR, NMR, ESR spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to characterize the synthesized materials. The formation of the polymer backbone and the addition of amine and phenolic groups were verified by FTIR and NMR data. Unpaired electrons were found by ESR analysis, suggesting electroactive behavior. While SEM images revealed a comparatively uniform morphology, TGA showed good thermal stability. The materials that were obtained show promise for use in electrochemical systems and sensors.