Volume 94, Nº 4 (2024)

It was found that the reaction of malonic acid N-arylamidoesters with ethyl 2-cyano-3-ethoxyacrylate in ethanol in the presence of equimolar amounts of triethylamine both at room temperature and under reflux leads to the formation of previously unknown diethyl 6-amino-1-aryl-2-oxo-1,2-dihydropyridine-3,5-carboxylates with yields of 40–70%. Structure of the obtained compounds was confirmed by NMR and IR spectroscopy data. Antibacterial activity of some of the obtained compounds was studied.

New substituted spiropyrrole(zi)dynes were synthesized by the 1,3-dipolar cycloaddition reaction of ylidenemalononitriles and azomethine ylides generated in situ by condensation of isatin and α-amino acids (sarcosine, proline). The products′s features of the regio- and diastereochemical structure were elucidated depending on the nature of the amino acid and the reaction conditions. Based on data from the analysis of the spectra of cycloaddition products obtained under various conditions, as well as some additional experiments, a probable scheme for the formation of products was proposed, including retro-1,3-dipolar cycloaddition and the retro-Mannich reaction. Methods for the selective synthesis of isomeric spiropyrrolizidines were developed.

The interphase distribution of microquantities of ReO₄^– between aqueous solutions of mineral acids and solutions of oligodentate β-aminophosphoryl compounds in organic solvents was studied. The stoichiometry of the extracted complexes was determined, the influence of the concentration of HClO₄, HNO₃, HCl and H₂SO₄ in the aqueous phase, the structure of the extractant and the nature of the organic solvent on the efficiency of the transition of ReO₄^– ions into the organic phase was considered. The possibility of selective extraction and concentration of Re(VII) with a complexing sorbent obtained by non-covalent attachment of tris[bis(2-diphenylphosphorylethyl)aminoethyl]amine on the surface of the macroporous polymer Amberlite XAD7HP was demonstrated.

An analysis of fractions extracted from polydimethylsilanes, as well as distillates obtained during the synthesis of poly(oligo)carbosilanes was carried out. By the methods of gel permeation chromatography and chromatography-mass spectrometry, the range of molecular weights in extracts and distillates, the composition and structure of compounds, as well as the sequence of their retention times on the chromatographic column were determined. It was established that the compounds extracted from polydimethylsilanes are low molecular weight cycles containing methylsilane and/or methylsiloxane units. In distillates, compared with extracts, the number of low molecular weight compounds containing individual or mixed methylsilane, carbosilane and siloxane units increases.