Pyrrole and its derivatives are representatives of azaheterocyclic systems with a powerful synthetic range, pronounced biomedical potential, and wide application. In addition, the pyrrole cycle is a basic structural element of vital porphyrin macrocycles, which are key fragments of chlorophyll, heme, vitamin B12, and bile pigments. In recent decades, significant attention of researchers focused on developing methods for obtaining various types of functionalized pyrroles as potential sources of bioactive compounds. Among them, pyrrole derivatives with a synthetically significant aldehyde group and halogen atoms are of particular interest. At the same time, the mass of accumulated original works devoted to the synthesis and chemical transformations of most of their types requires generalization. This, in turn, became a strong basis for a detailed analysis and systematization of methods for the synthesis and directed structural modification of halogenated (di)formylpyrroles in reports published during 2000-2025.

Through cyclization of 4-(dichloromethylene)-5-(aminosulfonylimino)imidazolidin-2-ones by formaldehyde action series of 8-(dichloromethylene)-3,4,7,8-tetrahydro-6H-imidazo[5,1 c][1,2,4,6]-thiatriazin-6-one 2,2-dioxides were synthesized. The PMB-deprotection from the 3rd position of created heterocyclic system and further 3N-alkylation were realized. Their structure parameters were discovered by NMR experiments and X-Ray analysis. The separate products (with allyl, carbethoxymethyl, 2-N-Boc-aminoethyl, 2-(N-Boc-N-isopropoxymethylamino)ethyl substituents in position 3) demonstrated high antiproliferative activity.

Methodology is reported for the synthesis of a six-membered heterocyclic ring involving cyclocondensation reaction through sulfur-sulfur bond formation. This method of synthesis allows for developing a new class of dithiadiazines. A series of bis-[6-tetra-O-acetyl-β-D-glucopyranosylimino-1,2,4-triazolo[3,4-b]-1,2,4,5-dithiadiazin-4-yl] alkanes have been synthesized by using a reagent, tetra-O-acetyl-β-D-glucopyranosylimino chloromethane sulfenyl chloride and bis-(4-amino-5-mercapto-1,2,4-triazol-3-yl) alkanes. These newly formulated N-glycosylated molecules could serve as a potential biological entity.

In this research, new azochalcone derivatives (6, 7) were synthesized by using three methods: the first one is diazotization - coupling method of different aromatic amines (sulfanilic acid, 2-aminopyridine) with chalcone (5), the second, aldol condensation method of azoaryl hydroxyacetophenone compounds with 4-dimethylamino benzaldehyde in presence of sodium hydroxide as a catalyst, the last one is method of aldol condensation of azoaryl hydroxyacetophenone compounds with 4-dimethylaminobenzaldehyde in presence of piperidine as an organic catalyst. The yield was the best by using the aldol condensation method with sodium hydroxide as a catalyst. New azoflavone derivatives (8, 9) with good yields (78-84 %) were also synthesized by performing cyclization reactions of azochalcone derivatives using iodine in dimethyl sulfoxide. The identity of the new compounds was determined using spectroscopic methods (FT-IR, 13C-NMR, 1H-NMR).

In the present work, we presented an efficient synthesis and anticancer activity evaluation of some new 3-R-6-(5-arylfuran-2-yl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles. We have shown that the proposed synthetic protocols provided the possibility to design triazolothiadiazoles diversity with a considerable chemical novelty. The structures of target substances were confirmed by using 1H NMR spectroscopy, mass spectrometry and elemental analysis. The synthesized compounds were selected by the National Cancer Institute Developmental Therapeutic Program for the in vitro cell line screening. Among all the substances tested, three compounds exhibited significant cytotoxic activity.

Five imidazo[1,2-c]pyrimidine and pyrimido[1,6-a]pyrimidine derivatives were designed, synthesized and evaluated for their antiproliferative activity and cytotoxicity. Primary bioassays in vitro showed that two of five synthesized compounds, 6-benzyl-8-(methylsulfonyl)-2,6-dihydroimidazo[1,2-c]pyrimidin-5(3H)-one, and 9-(methylsulfonyl)-7-propyl-2,3,4,7-tetrahydro-6H-pyrimido[1,6-a]pyrimidin-6-one possessed potent antiviral activity against BKV (EC50: 0.66 μM and 0.96, respectively). The selectivity index of these compounds is similar to that of cidofovir. Although antiviral activity was evident in secondary assays, significant virus inhibition occurred at or near the cytotoxic concentration (SI90=1). Here we show that substituted pyrimidine derivatives are a promising structure class of chemical compounds for the development of antiviral drugs against BKV infections. Hence these compounds may be taken as lead compounds for further development of novel antimicrobial and anticancer agents.