Russian Chemical Bulletin最新文献

The reaction of diisobutyl ketone azine with phosphorus trichloride in acetonitrile occurs in two steps. The first step affords 2-(2,6-diniethylhept-3-en-4-yl)-5-isobutyl-4-isopropyl-2H-1,2,3-diazaphosphole (2). The subsequent reaction of this intermediate with PCl₃ gives 1,4-dichloro-3,6-diisobutyl-2,5-diisopropyl-1H,4H-3a,6a-diaza-1,4-diphosphapentalene (3) in 52% yield. The reduction of compound 3 with magnesium metal in THF produces 3,6-diisobutyl-2,5-diisopropyl-1H,4H-3a,6a-diaza-1,4-diphosphapentalene (4) in 57% yield. The complexation of 4 with an excess of CuCl affords the coordination polymer [4(CuCl)₄]_n (5), in which each phosphorus atom is coordinated to two copper atoms. In the presence of an excess of the ligand, the reaction gives [4(CuCl)₂] (6).

An approach to the synthesis of hybrid multitarget compounds based on 4-amino-2,3-polymethylenequinolines (analogs of the drug tacrine) with different sizes of the aliphatic ring, which are coupled with a vanillin fragment as an antioxidant pharmacophore, was developed. The coupling was accomplished through the amide bond using an alkylamine linker. The synthesized hybrid compounds were found to highly efficiently inhibit cholinesterases, showing selectivity for butyrylcholinesterase, displace propidium cation from the peripheral anionic site of acetylcholinesterase (AChE), i.e., they are able to block AChE-induced aggregation of β-amyloid, and demonstrate high antioxidant activity. Compound 9c with a largest aliphatic ring size (C₇), which exerted a multitarget effect on the studied targets, can be used as a potential candidate for further research on the extention of the spectrum of its biological activity.

The composition and physicochemical properties of magnetically susceptible composites based on titanium dioxide and magnetite and obtained by heterocoagulation of oppositely charged hydrosols, were studied. The photocatalytic activity of systems with different ratios of oxides was investigated in the oxidation reactions of rhodamine B (RhB) and 4-acetaminophenol (APAP). Unlike the oxidation of APAP, the photodegradation of RhB in the presence of TiO₂—Fe₃O₄ hybrid particles is induced not only by UV radiation, but also by visible light, which is explained by the sensitization of the titanium dioxide surface. The introduction of negatively charged magnetite particles to titanium dioxide particles generally leads to a slight decrease in photocatalytic activity, although the system retains the ability to effectively degrade organic matter (>95%). The formation of magnetic heteroaggregates imparts magnetic sensitivity to the samples and enables the regeneration of the photocatalyst under the influence of an external magnetic field.

Novel synthetic approach to 3-quinazolinyl- and 3-quinoxalinyl-containing 7-aminocoumarins via nucleophilic substitution of hydrogen in the corresponding diazines has been developed. The proposed method employs readily available reagents and simple synthetic procedures without any catalysts based on the transition metals.

Mg-substituted bismuth niobates codoped with Group 13 elements (Al³⁺, Ga³⁺, and In³⁺) were synthesized. The samples are characterized by a pyrochlore-type structure. X-ray diffraction analysis was used to refine the crystal structure of the compounds, the distribution of Mg²⁺ cations at the B sites and p-element cations at the A and B sites in equal parts was determened. The diffuse reflectance spectroscopy was used to determin the band gap for the direct electronic transition (E_g^dir = 3.2–3.3 eV). The impedance spectra were analyzed: the dielectric characteristics and the conductivity type were determined. The compounds display dielectric behavior up to a temperature of 200 °C, and oxygen transport occurred above 400 °C.

The chemosensor properties of photochromic spironaphthoxazine 3,3-dimethyl-1-octadecyl-1,3-dihydrospiro[indoline-2,3′-naphtho[2,1-b][1,4]oxazin]-9′-ol in acetonitrile and at the air/water interface were studied. The selective interaction of the photochrome with aluminum(iii), mercury(ii), and lead(ii) cations was observed. The sensitivity and kinetics of the complexation were studied. This spiro compound has a high potential for application as a working element for the detection of the indicated cations.

In order to improve the solubility of 3,5-bis(arylidene)piperidin-4-ones with various substituents in the benzene ring, the corresponding 2-(2-methoxyethoxy)ethyl-[3,5-bis-(arylidene)-4-oxo-1-piperidinyl]acetates were obtained. Evaluation of their physicochemical characteristics in silico showed that the inclusion of 2-(2-methoxyethoxy)ethanol with an OMe terminal group in the piperidone molecules improves its pharmacokinetic characteristics and, as a consequence, its solubility in aqueous media and cytotoxic profile.

The review summarizes the literature data and our own results on the synthesis of low-molecular-weight derivatives based on α- and γ-mangostins, which are natural xanthones, and also presents current information on their biological activity.

A stable (ζ-potential of +56 mV) aluminum oxyhydroxide (AlOOH) hydrosol was obtained. Its dispersed phase consisted of plate-like particles with a pseudo-boehmite structure. Electrophoretic light scattering, FTIR and UV—Vis spectroscopy were used to study surface modification of the nanoparticles with chlorogenic acid (CGA). During the interaction, the isoelectric point shifted towards a less alkaline region, and a decrease in the ζ-potential of the hybrid particles and the pH of the medium were observed. These changes are related to a partial neutralization of the surface hydroxy and carboxy groups and a release of protons from the surface into the dispersion medium. Adsorption of CGA onto the AlOOH surface occurs instantaneously and is accompanied by the transition of the acid into its deprotonated forms (HCGA²⁻/CGA³⁻), despite the near-neutral environment. Binding occurs both via the carboxy groups of the quinic acid moiety and the phenolic hydroxy groups of the caffeic acid moiety. The absence of desorption in the presence of KCl and negligible desorption in the presence of K₂SO₄ point to a strong binding affinity of CGA to the nanoparticle surface. The obtained results confirm that AlOOH nanoparticles are highly promising objects for use as carriers for the immobilization of phenolic acids, which is demonstrated by considering CGA as a representative example.

Chalcones with a tert-butyl substituent in ring A were obtained from previously synthesized isomeric tert-butyl(dihydroxy)acetophenones. Oxidative cyclization of 2′-hydroxychalcones in the I₂—DMSO system promotes the formation of the corresponding flavones in high yields. Cyclization under the conditions of the Algar—Flynn—Oyamada reaction results in tert-butylflavonols.