A new method for obtaining 4-(2-methyl-1,3-oxazol-5-yl)benzenesulfonamide, an antiglaucomatous drug candidate oxazopt, was developed using a diazotization reaction. A combined potentiated effect of the antimicrobial action of carbapenems (meropenem) and aminoglycosides (gentamicin) against antibiotic-resistant gram-positive bacteria Enterococcus faecium, Enterococcus faecalis and gram-negative bacteria Escherichia coli, and antimonooxidase effect in vitro was revealed for this compound.

This study reports an improved diastereoselective synthesis of substituted spiro[chromane-2,4′-pyrimidin]-2′(3′H)-ones via the acid-catalyzed condensation of 6-styryl-4-aryldihydropyrimidin-2-ones with resorcinol, 2-methylresorcinol, and pyrogallol. The optimized method allows for the isolation of diastereomerically pure products, with stereoselectivity controlled by varying acid catalysts (e.g., methanesulfonic acid vs. toluenesulfonic acid) and solvent conditions. The synthesized compounds were evaluated for antimicrobial and antioxidant activities. Notably, the (2S*,4R*,6′R*)-diastereomers exhibited significant antibacterial activity against both Gram-positive and Gram-negative bacterial strains with minimal inhibition concentration down to 2 µg/mL, while derivatives containing vicinal bisphenol moieties demonstrated potent antioxidant activity, with IC₅₀ values (12.5 µg/mL) comparable to ascorbic acid. Pharmacokinetic analysis of selected hit compounds revealed favorable drug-like properties, including high gastrointestinal absorption and blood-brain barrier permeability. These findings highlight the potential of spirochromane-pyrimidine hybrids as promising candidates for further development in the treatment of infectious diseases and oxidative stress-related pathologies.

Method for the preparation of N-arylamino-1,2,4-oxadiazol-5(4H)-ones via reduction of N-nitrophenyl-1,2,4-oxadiazol-5(4H)-ones with tin(II) chloride has been developed. The results of experiments to study photophysical properties showed that the synthesized compounds have potential for use as fluorophores in the visible region of the spectrum. In addition, one of the obtained N-arylamino-1,2,4-oxadiazol-5(4H)-ones demonstrate antibacterial activity against both Gram-positive (S. Aureus) and Gram-negative (E. Coli) strains.

A series of new alkoxy derivatives and hydrazides was synthesized based on tetrahydrochromeno[2,3-d]pyrimidinones. The obtained compounds were tested for antimicrobial activity against reference strains of gram-positive (Staphylococcus aureus ATCC-25923), gram-negative (Escherichia coli C1, Pseudomonas fluorescens A1) bacteria and fungi (Candida albicans ATCC 10231). Chlorine-substituted hydrazide showed the highest activity against Staphylococcus aureus ATCC-25923 (MIC 32 µg/mL) and Pseudomonas fluorescens A1 (MIC 16 µg/mL), which indicates the prospects of this structural type for further medical and chemical optimization.

The thiouronium salts of chromeno[4,3-d]pyrimidine-2-thiones were isolated as individual diastereomers and characterized by ¹H, ¹³C NMR spectroscopy and mass spectrometry data. Antibacterial and antifungal activity against sensitive strains of gram-negative (E. coli and P. fluorescens) and gram-positive bacteria (S. aureus), and C. albicans fungi was studied.