Volume 89, Nº 7 (2019)

Functionally substituted chalcones, pyrazolines, and flavonones have been synthesized. Their structure has been studied by means of ¹H and ¹³C NMR spectroscopy, including COSY and HMQC experiments. Anti-inflammatory activity of the synthesized chalcones, pyrazolines, and flavonones has been evaluated.

Depending on the reaction conditions, the acylation of 2-ethylnaphtho[2,1-b]furan leads to the formation of a mixture of 1-acetyl-, 5-acetyl-, and 1,5-diacetyl derivatives with a widely varying ratio of components, the structure of which has been characterized by IR and NMR spectroscopy, mass spectrometry, and X-ray diffraction analysis methods. Quantum-chemical simulations using the DFT B3LYP/6-311++G** method have reproduced the experimental geometry of isomeric acetyl[2,1-b]furans and indicated their close thermodynamic stability. However, the Fukui indices of the reactivity f⁻ have indicated the preference of the primary attack of the electrophile at the C⁵ position (f⁻ = 0.18) as compared to the C¹ position (f⁻ = 0.06).

Ring opening of 5-tert-butyl-3-[(9H-fluoren-9-ylidene)hydrazinylidene]furan-2(3H)-one by the action of primary amines afforded a series of new 2-[(9H-fluoren-9-ylidene)hydrazinylidene]-5,5-dimethyl-4-oxohexan-amides. The synthesized compounds were tested for antinociceptive and antimicrobial activities.

Glycosylation of 4-(4-hydroxyphenyl)-1,2,3-thia(selena)diazoles with 1-α-bromo-2,3,4,6-tetra-O-acetyl-D-glucopyranose, 1-α-bromo-2,3,4,6-tetra-O-acetyl-D-galactopyranose, and 1-α-bromo-2,3,5-tri-O-acetyl-D-xylopyranose under the conditions of interphase catalysis has afforded the corresponding acetylated glycosides. An alternative pathway of selenadiasole glycosides synthesis from semicarbazones of 1-β-O-(4-acetylphenyl)-2,3,4,6-tetra-O-acetyl-D-glucopyranose, -2,3,4,6-tetra-O-acetyl-D-galactopyranose, and -2,3,5-tri-O-acetyl-D-xylopyranose via oxidation with selenium dioxide has been elaborated.

The interaction of styryl derivatives of pyridine N-oxides with proton donors in various solvents was studied. UV-Vis spectroscopy and thermogravimetric analysis were applied to determine the spectral and thermo-chemical characteristics of the resulting molecular complexes. The dependences of the thermodynamic parameters of the complexes on the N-oxide structure and on the solvating medium were established. The DSC method was used to determine the temperature and enthalpy characteristics of the desolvation and melting processes for both N-oxides and their complexes with proton donors.

The DFT (U)PBE0 method was used to calculate the structural parameters of the C₅H₅Yb·, C₅H₅Lu, C₈H₈Lu·, C₈H₈Yb, (C₅H₅)₂Yb, (C₅H₅)₃Yb, C₅H₅YbC₈H₈, C₅H₅Ce·C₈H₈, C₅H₅LuC₈H₈, (C₈H₈)₂Lu, (C₈H₈)Ce*, (C₈H₈)₂Ce, (C₈H₈LuC₈H₈)₂Yb, and (C₈H₈Ce·C₈H₈)₂Yb molecules. In the (C₈H₈)₂Ce molecule, the oxidation state of the lanthanide is higher than in the quadruple-decker (C₈H₈LnC₈H₈)₂Yb complexes, in the C₅H₅LnC₈H₈ molecules, and in the free radicals (C₈H₈)₂Ce* and (C₈H₈)₂Lu. Oxidation of (C₅H₅)₂Yb with cyclooctatetraene and the binding of the (C₈H₈)₂Ln molecules by ytterbium(II) are exothermic reactions. The atomic charges and the dipole and quadrupole moments are indicative of incomplete transfer of the lanthanide valence electrons to the ligands, i.e., of a significant covalent component of the η⁵ and η⁸ bonds. Lutetium interacts with cyclooctatetraene as a lanthanide, without showing the properties of transition metals.

Models of multiple linear regression and multilayer artificial neural network have been developed for modeling and predicting the stability constants of sodium and potassium coronates basing on the properties of aqueous-organic solvents (water-methanol, water-propan-2-ol, water-acetonitrile, and water-acetone). The values of the coronates stability constants in water-ethanol solvents have been predicted, and the predictions of the models of multiple linear regression and an artificial neural network models have been compared. The contributions of electrostatic, cohesive, and electron-donating interactions to the increase in the stability of the coronates have been quantitatively assessed basing on the models of multiple linear regression and the principle of free energies linearity. Neural network models based on unsupervised (multilayer perceptrons) and supervised (Kohonen networks) learning algorithms have been developed to classify the stability of sodium and potassium coronates. The neural network classifiers have fully confirmed the classification of the coronated stability via the k-means exploration method.

This review deals with one of the most important classes of nanomaterials — oxide nanoparticles. Preparative methods for the synthesis of nanooxides, their hydro- and organosols, and methods for the chemical surface modification of oxide nanoparticles are comprehensively reviewed. The high surface area of nanooxide particles and their relatively low porosity allows efficient modification of the surface to obtain highly selective sorbents, microheterogeneous catalysts, biocompatible magnetic and fluorescent labels, means of drug delivery or removal of harmful components from living systems, and objects of environmental monitoring.

A series of new 2-{3-{4-[(5-aryl-1,2,4-oxadiazol-3-yl)methoxy]phenyl}isoxazol-5-yl}-N-(3,4,5-tri-methylphenyl)thiazol-4-amine derivatives is synthesized, and the structures of products are confirmed by 1H and 13C NMR, and mass spectra. The new compounds are tested for their anticancer activity against human cancer cell lines: MCF-7 (breast), A549 (lung), Du-145 (prostate), and MDA MB-231 (breast) by using MTT assay and etoposide as a standard reference. All compounds demonstrate good to moderate activity on all cell lines.

A series of novel functionalized N-substituted 5, 6-dimethoxy-1H-indole derivatives is synthesized. All products are evaluated for antibacterial activity using rifampicin and ciprofloxacin as standard drugs and identified as the promising compounds for further studies. The products are screened for their anticancer activity against MCF7 cell line (breast cancer cell-line) using MTT assay. Two compounds display a significant activity against MCF7 cell line at a very low concentration. The structure-cytotoxicity relationship is supported by molecular docking studies of the active compounds against 3S7S receptor.

Symmetrical fatty dialkyl carbonates make a group of chemicals that has great potential for applications as phase change materials (PCMs). In this study, various parameters affecting synthesis of these carbonates are studied on laboratory scale, which includes: reactants ratio, reaction temperature and time, and the amount of catalyst used. Structures of the desired products are identified using FTIR and NMR spectroscopy. Differential scanning calorimetry (DSC) analysis is used for determining potential of the synthesized symmetrical fatty dialkyl carbonates as PCMs for energy-saving applications.

A series of thieno-pyrimidine derivatives are synthesized from 5′-amino-2,3′-bithiophene-4′-carboxylate via the corresponding intermediate N-benzoylated carboxamide derivatives. The target compounds are tested for antibacterial and antifungal activity. Some of the synthesized compounds demonstrate potent antibacterial activity with LD₅₀ comparable with the reference drug indomethacin.

4-(1-Naphthyl)-1,2,3-thiadiazole is readily decomposed under the action of potassium tert-butylate with the release of nitrogen and the formation of potassium 2-(1-naphthyl)ethynylthiolate. Upon further treatment of the reaction mixture with excess of alkyl halide, the corresponding alkyl 2-(1-naphthyl)-1-ethynylsulfides have been obtained. In the case of the reaction with allyl bromide, the resulting sulfide has undergone rearrangement. A mixture of Z- and E-isomers of 2-(1-naphthyl)-1-ethynyl-1-propenylsulfide has been obtained as the product of allylic rearrangement instead of the expected product of the thio-Claisen rearrangement.