A three-step method for obtaining pyrrolo[1,2-a]pyrazine-4,7-dicarboxylates was presented. The method involves the N-alkylation of 5-formylpyrrole-3-carboxylates with bromoacetate, followed by the aminoalkenylation of the N-alkoxycarbonylmethyl group using dimethylformamide di-tert-butyl acetal, and further annulation of the pyrazine ring in the presence of ammonium acetate. Procedures for selective hydrolysis, halogenation, arylation, and alkynylation of the synthesized dicarboxylates were described. The in silico evaluation of the potential bioactivity of the synthesized dicarboxylates 4a–f, dicarboxylic acids 7a–c,e, halogenated dicarboxylates 8f–j, and dicarboxylic acids 10a–e was carried out. As seen from the screening of antimicrobial activity, the synthesized compounds 7a–e, 8c,f–j, 10a–e exhibit inhibitory and bactericidal activity against several bacteria and fungi. The highest activity against Klebsiella pneumonia, Staphylococcus aureus, and Bacillus subtilis has been established for the compound 8f with a MIC of 15.625 µg/mL, and the highest antifungal activity against Candida albicans was found for the compounds 8f, 8g, and 8i (МІС=15.625 µg/mL). The molecular docking data show that the compound 8i has the highest affinity to the ThiM Klebsiella pneumoniae kinase, and compounds 8i, 8j are noted for their highest affinity to the DNA gyrase from Staphylococcus aureus.

Thiazolo[3,2-a]pyrimidines are structural analogues of biogenic purine bases, thus may be considered as potential purine antagonists. The synthesis of these heterocyclic systems attracts significant attention from researchers in the field of organic and medicinal chemistry due to their wide range of biological activities, e.g. anti-inflammatory, antimicrobial, antioxidant, antiviral, and anticancer. The high bioactivity of thiazolo[3,2-a]pyrimidine derivatives stimulates the development of fundamentally new synthesis options, which include modern catalytic, microwave and ultrasonic methods for activating cycloaddition reactions, and the improvement of already known methods. This, in turn, became a strong basis for summarizing and systematizing the existing array of literature sources from 2000 to 2024 relating to the methods of obtaining and biomedical profile of thiazolo[3,2-a]pyrimidines and their hydrogenated analogues.

The Giese reaction is a key method for forming C–C bonds via the radical addition to electron-deficient alkenes. Recent advances have shifted this transformation towards photocatalytic approaches that use visible light to generate carbon-centered radicals under mild and sustainable conditions. This review highlights developments from 2020 to 2025 in photocatalytic radical generation using metal-based complexes (especially ruthenium and iridium) and organic photocatalysts. Emphasis is placed on how light-driven processes enable efficient, selective, and environmentally friendly Giese-type reactions with diverse substrates. These innovations demonstrate the growing importance of photochemistry in modern radical synthesis.

The method for the synthesis of ethyl 4-[3-(ethoxycarbonyl)-1-phenyl-1H-pyrazol-4-yl]-2-oxo/thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates was developed, and the bioactivity of the obtained compounds against infectious agents was predicted. Docking studies of the synthesised compounds were performed on pteridine reductase 1 (PTR1) of Leishmania, dihydrofolate reductase–thymidylate synthase of Trypanosoma cruzi, and human dihydrofolate reductase. The results demonstrated that the investigated compounds exhibit high affinity for these enzymes. Moderate selectivity relative to human DHFR was also observed. In addition, the predicted drug-likeness, ADME-Tox parameters, and toxicity profiles suggest the potential of the synthesised compounds for further pharmacological development.

A number of 5-dichloromethylidene-4-sulfonyliminohydantoins were synthesized by the reaction of 2-amino-3,3-dichloroacrylonitrile (ADAN) with aryl and alkyl isothiocyanates. These products are polyfunctional molecules that are considered as initial materials for the synthesis of bioactive compounds. The method of such derivatives multigram synthesis was optimized; also, the features of purification were described, and the main products of reaction mixture alcoholysis (acyclic carbamates) were identified for the first time. A number of modifications was carried out on the example of 5-dichloromethylidene-4-tosyliminohydantoin, namely: alkylation, hydrolysis of the amino group with subsequent arylation, substitution reaction with S-nucleophile, Suzuki – Miyaura coupling, and reduction of the dichloromethylidene fragment to the methyl group. The anticancer activity of 5-dichloromethylidene-4-tosyliminohydantoin was shown.

It has been shown that 3-formylpyrazolo[1,5-a]pyrazine-4-carboxylates obtained by the selective formylation of pyrazolo[1,5-a]pyrazine-4-carboxylates react with 1,2-ethanediamine or 1,3-propanediamine in methanol at room temperature to give pentaazacyclopenta[d]acenaphthalenes or pentaazaaceanthrylenes.

Angular pyrrolo(pyrido)[1,2-a]quinazolinones, being structurally isomeric to linear pyrrolo(pyrido)[2,1-b]quinazolinone alkaloids, are attractive molecular systems for both synthetic transformations and targeted biomedical research. The pyrrolo(pyrido)[1,2-a]quinazolinone scaffold has proven to be quite effective in the search for compounds with a wide range of pharmacological activities, e.g. anti-inflammatory, antioxidant, antibacterial, antiarrhythmic, and inhibitors of important biotargets. The present review summarises the methods for the synthesis of pyrrolo(pyrido)[1,2-a]quinazolinones as a comprehensive research object, especially in the past decade. They are systematised according to the type of heteroannulation and include the processes of cascade annulation of the pyrimidine and pyrrole (pyridine) cycles to anthranilamides (hydrazides); formation of a pyrimidine nucleus based on ortho-pyrrolyl(pyridinyl) substituted aromatic compounds; annulation of the pyrrole (pyridine) nucleus to a quinazolinone scaffold. It is expected that the generalised material presented will serve as a reliable guide for the rational design of new pharmacologically oriented compounds.

A combined experimental and theoretical study of the fundamental thermodynamic parameters of 3-(5-phenyl-1-(pyridin-3-yl)-1H-pyrrol-2-yl)propanoic acid was carried out for the first time. The enthalpies of combustion, formation in the condensed state, fusion, and vaporization were determined using high-precision equipment. Based on the experimentally obtained results, the enthalpies of sublimation and formation in the gaseous state at 298.15 K were calculated using two methods. The possibility of applying analytical methods of Domalski, Joback and quantum chemical calculations to determine the enthalpy of formation in the gas phase is analysed.

Triazolo[3,4-b][1,3,4]thiadiazole molecules are found to be important tools in modern bioorganic and medicinal chemistry. This condensed system successfully combines two pharmacologically significant five-membered heterocycles – 1,2,4-triazole and 1,3,4-thiadiazole, which causes much more interest in the enhanced activity profile of its analogs than their parent separate constituents. It’s considered that the triazoles fused to thiadiazoles exhibit various therapeutically important properties, probably due to the existence of N-C-S fragments in their structures. In this review, we presented the summarized literature data about the diversity of pharmacological effects of [1,2,4]triazolo[3,4-b][1,3,4]thiadiazole based compounds as promising objects for the rational design of drug-like molecules.

Antioxidant activity of a series of previously described 5-amino-N-(iododi(per)fluoroalkyl)-1H-1,2,3-triazole-4-carboxamides 3a-r, their synthetic precursors 5-amino-N-allyl-1,2,3-triazole-4-carboxamides 1a-g, and their deamination products N-(3-di(per)fluoroalkyl-2-iodo-n-propyl)-1,2,3-triazole-4-carboxamides 4a-e was investigated in vitro using DPPH test and ascorbic acid as a standard reference. It was established that compounds 3a-r inhibit DPPH free radicals in moderate to high values (50.9–97.6%). The effect of substituents in the position 1 of the 1,2,3-triazole nucleus, fluoroalkyl groups and amino groups on the level of antioxidant activity was studied in detail. Reactivity and electrostatic surface potential were evaluated for the most active carboxamides 3a,g,r using the DFT method, and molecular docking was studied in the NADPH oxidase protein model.