Vol. 20 No. 2 (2022)

Virtually unknown in her homeland, Bianka Tchoubar, born in 1910 in Kharkiv, brought about a true paradigm shift in French organic chemistry of the 20th century. Originality of research ideas, scientific rigor and legendary perseverance earned her respect and recognition in the world scientific community. This eccentric Parisian of Ukrainian origin became the first woman to enter the French National Center for Scientific Research (Centre National de la Recherche Scientifique, CNRS) upon its creation in 1939. Bianka Tchoubar’s contribution to the study of reaction mechanisms and salt effects in organic chemistry were of paramount importance, and so were her efforts to present these novel scientific concepts to the audience of French organic chemists through the clear and concise expression of her books. The name of this great Ukrainian researcher may be found in the pages of French organic chemistry textbooks, where the Demjanov ring expansion reaction is called the Demjanov–Tiffeneau–Tchoubar rearrangement. This article aims at presenting the outstanding scientific legacy and turbulent life path of this researcher to the world scientific community.

Aim. To synthesize aliphatic and aromatic derivatives of salt carbenoid compounds of the series of imidazole, benzimidazole, pyridine, pyrimidine and 1,3,4-oxadiazole containing fluorophenyl, cetyl or adamantyl substituents, and study their antimicrobial (antibacterial and antifungal) activities.
Results and discussion. New derivatives of heterocyclic carbenoid salts and zwitterions based on the imidazole, benzimidazole, pyridine, pyrimidine and 1,3,4-oxadiazole heterocyclic systems containing fluorophenyl, cetyl or adamantyl substituents were synthesized. For this purpose, reactions of cyclization of the corresponding diimines with ethoxymethyl chloride (imidazolium salts), quaternization of the corresponding azoles with cetyl bromide or 1-adamantyl bromide in organic solvents (benzimidazolium, pyridinium and 1,3,4-oxadiazolium salts), cyclization of di(1-adamantylamino)alkanes hydrobromides with the orthoformic ester (4,5-dihydroimidazolium and tetrahydropyridinium salts) were used. Zwitterionic compounds were obtained by the reaction of the corresponding azolium salts with phenyl isothiocyanate in the presence of potassium carbonate. Some macrocyclic and adamantyl substituted heterocyclic compounds showed antifungal and antibacterial activities.
Experimental part. The structure of the compounds synthesized was proven by ¹H and ¹³C NMR spectroscopy methods. The antimicrobial activity was studied out by the agar diffusion method to determine diameters of the growth inhibition zones of microorganisms (bacteria and fungi) and by the method of serial dilutions to determine the minimum inhibitory concentration and minimum bactericidal and fungicidal concentrations.
Conclusions. The synthesis of new heterocyclic carbenoid salts and zwitterions based on the imidazole, benzimidazole, pyridine, pyrimidine and 1,3,4-oxadiazole heterocyclic systems containing fluorophenyl, cetyl or adamantyl substituents has been performed. Compounds of macrocyclic and adamantyl heterocyclic series with antifungal and antibacterial activities have been found. 1,3-Dicetylimidazolium bromide, macrocyclic bis(decylenebenzimidazolium) bromides, azolium-N-phenylthiocarboximides have been proven to be the most active.

Aim. To analyze and summarize the synthetic potential of 1,2,3-triazole-4(5)-amines as efficient building blocks in the synthesis of triazolo-annulated pyridine, azine and azepine systems.
Results and discussion. Original literature sources revealing the synthetic potential of 4(5)-amino functionalized 1,2,3-triazoles as convenient and available building blocks for the preparation of triazolo-annulated pyridines, azines and azepines were analyzed and systematized. Condensation of 1,2,3-triazole-4(5)-amines with methylene active compounds was shown to be a powerful tool for the synthesis of versatile triazolo[4,5-b]pyridines. In turn, the cyclocondensation based on 5-amino-1,2,3-triazole-4-carboxylic acids and their structurally modified derivatives was proven to be a general way for obtaining a number of triazolo[4,5-d]pyrimidine systems. Few representatives of triazolo-annulated pyridazines, 1,3-oxazines and 1,3-thiazines were synthesized by the intramolecular cyclization of the corresponding 4-aryl(carboxy-, aminomethyl)-5-amino-1,2,3-triazoles. The cyclocondensation involving 4,5-diamino-, 4-carbofunctionalized 5-amino-1,2,3-triazoles and 4-amino-5-thiocarboxamido-1,2,3-triazoles was successful for the construction of di-, oxa- and thiazepino-annulated triazoles.
Conclusions. The analysis, systematization and summary of the literature regarding the synthetic potential of 1,2,3-triazole-4(5)-amines conclusively demonstrate that these structures are easily available and convenient molecular blocks for the construction of triazolo-annulated pyridine, azine and azepine systems that are important for synthetic and biomedical research.

Aim. To select “green conditions” for identifying components in a combined medicine for the treatment of alcohol intoxication.
Materials and methods. Thin-layer chromatography and high performance thin-layer chromatography methods were used. An analytical GREEnness calculator was applied to assess the environmental friendliness of the analytical procedure.
Results and discussion. The choice of mobile and stationary phases that comply with the principles of “green chemistry” and can be used to detect glutamic acid and glycine in the composition of a combined medicine has been substantiated. It has been determined that by the indicators R_f, R_s, ΔR_f, α, N, H the most effective for the division is the ethanol (96 per cent) – water (70:30) mobile phase (the length of the solvent front is 10 cm, the application volume is 5 μL), which allows, in addition to amino acids, to determine another prescription component – ascorbic acid. The conditions for identification of substances by the high-performance thin-layer chromatography method (the length of the solvent front is 7 cm, the application volume is 2 μL) have been selected. It has been found that to detect chromatographic zones, it is optimal to use ninhydrin solution R1 with further heating of the plate at a temperature of 100-105°С for 5 min. The specificity of determination of glutamic acid, glycine and ascorbic acid in comparison with solutions of standard substances has been proven. While studying the robustness of the method the influence of chromatographic conditions on the final result (the impact of the stationary phase type, chamber saturation, application volume, distance from the “start line” to the “finish line”, the effect of the detection solution, stability of solutions for application) has been researched. The precision of the method on one and three plates of the same type has been studied; the intermediate precision has been researched. The calculated assessment of greenness of the analytical procedure is 0.66.
Conclusions. As a result of the studies conducted, “green conditions” for identifying amino acids (glutamic acid, glycine), as well as ascorbic acid in a combined medicine by thin-layer chromatography and high-performance thin-layer chromatography methods have been selected. The validation characteristics of the method (specificity, robustness and precision) have been studied.