Volume 61, Nº 5 (2025)

cis-5-Arylpyrrolidine-2-carboxylates obtained in 1,3-dipolar cycloaddition reactions from arylaldimines of glycine and vinyl sulfones go through oxidative aromatization under the action of manganese(IV) oxide to the 5-aryl-2-pyrrolecarboxylates in high yield. Factors affecting the retention of the sulfonyl substituent in the pyrrole molecule have been established.

A method for the synthesis of a new 18-m embered nitrogen macroheterocycle was developed. It was based on the acid-catalytic cyclocondensation of 1-[(2E,Z)-2-hydrazono-2-phenylethyl]-5-methyl-1H-pyrazole-3-carbohydrazide, a reaction product of methyl 5-methyl-1-(2- oxo-2-phenylethyl)-1H-pyrazole-3-carboxylate with hydrazine.

Oxidation reactions of cage derivatives of quinopimaric acid – γ-diketone, oxa-“bird cage”, 18-chloro-15-oxa-“bird cage”, and 16-sulfanyl-15-oxa-“bird cage” were studied using a number of oxidizing agents: sodium percarbonate in trifluoroacetic acid at 0°C; 36% hydrogen peroxide in acetone at room temperature; tertiary butyl hydroperoxide in the presence of MoCl₅ at boiling in benzene. It has been shown for the first time that the oxidation reactions of diterpene oxa-“bird cages” lead to the formation of a mixture of ketolactones (Bayer–Villiger reaction products) with a predominance of mainly 7,10-dioxo-6-oxahepta-cyclo[11.8.0.0^3,8.0^4,12.0^5,11.0^9,13.0^16,21]henicosan.

By condensing o-phenylenediamine with 2(4)-aminobenzoic acids in 65% polyphosphoric acid at a temperature of 180–190°C for 4 h or by boiling the reagents in o-xylene in the presence of tetrabutoxytitanium, 2-(2(4)-aminophenyl)benzimidazoles were obtained, the acylation of which with methyl chloroformate in the presence of triethylamine led to the production of the corresponding benzimidazoles with a carbamate function. Condensation of o-phenylenediamine and 4-nitro-o-phenylenediamine with glycolic acid in the presence of 70–75% polyphosphoric acid with heating for four hours at 130°C yielded 2-hydroxymethylbenzimidazole with a yield of 81% and 5-nitro-2-hydroxymethylbenzimidazole with a yield of 84%, which, when treated with phenyl isocyanate in tetrahydrofuran at 27–30°C for 3.5 h, were converted into the corresponding benzimidazole derivatives with a yield of 84–86%. In order to find the most promising ones for further biological research, molecular docking of synthesized 2-substituted benzimidazoles, as well as previously obtained carbamate derivatives of pyridazine and N-allyl derivatives of 2-morpholinoethyl-N-phenylcarbamate and 2-(2-pyridinyl)ethyl-N-phenylcarbamate was carried out based on interaction with the enzyme glucosamine-6-phosphate synthase.

In this work, the synthesis of pyrrole derivatives based on azolo[1,5-a]pyrimidines (AP) using the Clauson–Kaas methodology is reported for the first time. It was found that within the series of azolo[1,5-a]- pyrimidine-6,7-diamines, the amino group at the 6-position reacts selectively. The developed method enables the synthesis of 6-(pyrrolyl)-[1,2,4]-azolo[1,5-a]pyrimidine-7-amines with yields of 64–85% and a high degree of purity. The reaction pathway is confirmed by NMR spectroscopy and X-ray structural analysis. The obtained results significantly expand the scope of azolopyrimidine modifications, opening new prospects for the targeted synthesis of functionalized derivatives.

A method was developed for the synthesis of fused benzo[b][1.4]oxazine monoadducts of С₆₀ fullerene in reactions with aminophenols (2-aminophenol, 2-amino-4-methylphenol, 2-amino-4-phenylphenol) in the presence of LiOH and Pb(OAc)₄. A probable mechanism for the reactions of obtaining condensed benzo[b][1,4]oxazine adducts has been proposed.

Condensation of 3-benzyl-2-thioxo-2,3-dihydro-1H-spiro[benzo[h]quinazoline-5,1'-cycloheptane]-4(6H)-one with 5,5-dialkyl-2-chloromethylbenzo[h]quinazolines were used to synthesize dibenzo[h]quinazoline compounds in which spiro[benzo[h]quinazoline-5,1'-cycloheptane] in the second position is linked via a -SCH₂- linker to another benzo[h]quinazoline molecule. The specified 2-thioxobenzo[h]quinazoline, under similar conditions, upon reaction with methylene iodide, forms 2,2'-[(methylenebis(sulfandiyl)]bis{3-benzyl-3H-spiro[benzo[h]quinazoline-5,1'-cycloheptane]}-4(6H)-one. A transition was made from the starting benzo[h]quinazoline to the 2-hydrazinoderivative, which is cleaved in the presence of caustic potash to form 3-benzyl-3H-spiro[benzo[h]quinazoline-5,1'-cycloheptane]-4(6H)-one. Based on the 2-hydrazino derivative, hydrazone, thiosemicarbazide, and 4-benzyl-4H-spiro[benzo[h][1,2,4]triazolo[4,3-a]quinazoline-6,1'-cycloheptanones] have been synthesized. Condensation of 4-benzyl-1-mercapto-4H-spiro[benzo[h][1,2,4]triazolo[4,3-a]quinazoline-6,1'-cycloheptane]-5(7H)-one with alkyl halides 1-sulfanyl-substituted triazolobenzo[h]quinazoline derivatives of various structures were obtained. The antibacterial properties of the synthesized compounds were studied.