A preparative procedure has been developed for the synthesis of a series of new medicinally relevant 3-aryl-5-(aryloxymethyl)-1,2,4-oxadiazoles in 46–66% yields by alkylation of substituted phenols with 3-aryl-5-(chloromethyl)-1,2,4-oxadiazoles in the system K₂CO₃/KI/DMF. Poorly studied 3-R-4H-1,2,4-oxadiazin-5(6H)-ones were synthesized by a new method based on the reaction of methyl chloroacetate with amidoximes in the superbasic system t-BuONa/DMSO. The synthesized compounds at concentrations of up to 250 μg/mL showed no antibacterial activity against sensitive strains of Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas fluorescens, which supposedly suggests their low toxicity for human intestinal and mucous microflora.

Methods were developed for the synthesis of a series of new thioethers, interesting for medical chemistry, by reacting 4-fluorothiophenol, 2-mercaptobenzoxazole and 5-methoxy-2-mercaptobenzimidazole with 3-aryl-5-(chloromethyl)-1,2,4-oxadiazoles. The conditions for the oxidation of the obtained thioethers into the corresponding sulfones were selected. Analysis of the results of screening of the prepared derivatives against sensitive strains of Escherichia coli, Pseudomonas fluorescens, Staphylococcus aureus, Bacillus cereus and Candida albicans showed the presence of high and moderate antibacterial activity in a number of compounds in drug concentrations up to 250 μg/mL.