Vol 93, No 8 (2023)

The Reformatsky reagent, derived from the methyl 1-bromocyclohexanecarboxylate and zinc, reacts with N′ -(arylmethylidene)benzohydrazides, to form, as a result of intramolecular cyclization of the initial addition products, N -(1-aryl-3-oxo-2-azaspiro[3.5]nonan-2-yl)benzamides. The structure of the latter was proved by X-ray diffraction analysis. In the case of p -tolualdehyde benzoylhydrazone, the adduct of the Reformatsky reagent to the double carbon-nitrogen bond of the substrate, which not underwent cyclization, was predominantly isolated. The resulting spiroazetidin-2-ones exhibit antinociceptive activity.

Reaction of acyl isothiocyanates of 2-allyl- and 2-benzylmaleopimarimides with 3-carboxy- and 2,4-dinitrophenylhydrazines and hydrazides of some aromatic acids (benzoic, 4-hydroxy- and 4-methoxybenzoic, nicotinic, isonicotinic) furnished linear hydrazinocarbonothioyl derivatives of these maleopimarimides in high yields. Structure of the synthesized compounds was determined by ¹H,¹³C, ¹H-¹³C HSQC, ¹H-¹³C HMBC, COSY, NOESY, and ¹H-¹⁵N HMBC NMR spectroscopy methods.

The reaction of 4-amino-6-aryl-2-halopyridine-3,5-dicarbonitriles with thioglycolic acid ethyl ester was used to synthesize a series of new efficient fluorophores of thieno[2,3- b ]pyridine series. The long-wavelength absorption bands of DMSO solutions of the prepared compounds are at the boundary of the UV and visible regions of the spectrum (λ_abs 375-388 nm) and show an ambiguous influence of the substituent electronic effect, that was explained by quantum chemical calculations. The emission maxima are in the yellow-green region (λ_em 490- 510 nm) and they are blue-shifted in the presence of electron donor groups with slightly increasing intensity (Φ_em 37.8-60.6%). It was found that the nitro group presence causes a complete photoluminescence quenching both in solution and in the solid state. In addition, the position of the emission maximum (λ_em 473-505 nm) and its intensity (Φ_em 3.6-72.7%) strongly depend on the polarity and the basic properties of the medium, that was established using the Catalan empirical model.

Within the framework of the density functional theory approximation, quantum-chemical calculations were performed and data on the structure and properties of charge-transfer complexes of 9,10-phenanthrenquinone nitro derivatives with 9-methyl-9 H -carbazole were obtained. The formation energies of complexes, the average distances between the donor and acceptor planes, and the values of charge transfer from the donor to the acceptor have been calculated. The crystal and molecular structure of the complex of 2,4,7-trinitro-9,10-phenanthrenquinone with 9-methyl-9 H -carbazole (C₁₄H₅N₃O₈·C₁₃H₁₁N) was determined by X-ray diffraction analysis. In the crystal of the complex, the donor and acceptor molecules form parallel stacks of the {-D-A-D-A-}_∞ mixed type with average interplanar distances of 3.29 and 3.35 Å. Each acceptor molecule forms intermolecular hydrogen bonds C-H···O 2.42-2.69 Å.

The amidoalkylation reaction of a phosphonous acid containing a structural isostere of diethyl glutamiate using ethyl carbamate and 3-(methylthio)propionaldehyde was proposed for the synthesis of phosphinic pseudo-NC(O) OEt-protected Met-Glu-peptide. Subsequent adamantyl protection of the phosphorylic function and hydrolysis of carboxylic groups made it possible to obtain phosphinic pseudo-Met-[P]-Glu in the form of cyclic glutamate anhydride. It was found that the latter reacts with the third amino acid component histidine to form the phosphinic Met-[P]-Glu-γ-His tripeptide.

The effect of trioctylammonium bis[(trifluoromethyl)sulfonyl]imide ionic liquid on the extraction of REE(III) with tetraoctyldiglycolamide from nitric acid solutions was studied. It was found that in the presence of an ionic liquid in the organic phase, the efficiency and selectivity of the extraction of metal ions from nitric acid solutions increases significantly. The influence of the acidity of the aqueous phase on the change in the distribution ratios of REE(III) was considered, and the stoichiometry of the extractable complexes was determined.

Microcrystalline upconversion materials NaY_{0.8- x} Yb_0.2Ho _x F₄ ( x = 0-0.1) were synthesized by hydrothermal synthesis for the first time. All the synthesized compounds have hexagonal β-NaYF₄ crystalline phase. Holmium(III) ions isomorphically replace yttrium ions. The maximum upconversion emission intensity is observed for NaY_0.78Yb_0.2Ho_0.02F₄ in the visible region of the spectrum upon excitation at a wavelength of 973 nm.

A study was conducted into the potential use of Lu₂O₂SO₄: x Eu³⁺ as a contrast agent in multifunctional medical imaging. Spherical powders of solid solutions Lu₂O₂SO₄: x Eu³⁺ ( x = 1-7 mol%) with a diameter of approximately 300 nm were synthesized through co-precipitation followed by calcination. The duration of synthesis was observed to impact particle morphology, with extended coprecipitation times leading to coarse particles that lost their spherical shape due to conglomerate formation. Exciting Lu₂O₂SO₄: Eu³⁺ at a wavelength of 270 nm results in distinct peaks appearing in the 610-620 and 690-710 nm regions, with intensity varying depending on the concentration of Eu³⁺ ions present.