Synthesis and antifungal properties of the new semiselenoglycolurils

The universal two-stage synthesis of 1-alkyl-4-methyl- and 1,3,4-trialkylsubstituted semiselenoglycolurils was realized on the basis of a range of semithioglycolurils, which were S-methylated to isothiouronium salts, followed by the interaction of the salts with NaHSe generated in situ from Se and NaBH₄. The resulting semiselenoglycolurils were tested as antimicrobials and exhibited selective inhibition of filamentous fungi. A broad comparison with previously reported analogs revealed their fungistatic mode of action and highlighted the significant influence of steric hindrance of the selenium atom on antifungal activity. These findings suggest that semiselenoglycolurils may possess a novel antifungal mechanism, warranting further detailed investigation of their molecular targets. In addition, 1,3,4-trialkylsemiselenoglycolurils effectively inhibit the growth of phytopathogenic fungi.