2-(1-Adamantyl)-2-methyl-pyrrolidines 3 and 4, 2-(1-adamantyl)-2-methyl-azetidines 5 and 6, and 2-(1-adamantyl)-2-methyl-aziridines 7 and 8 were synthesized and tested for their antiviral activity against influenza A. Parent molecules 3, 5, and 7 contain the α-methyl-1- adamantan-methanamine 2 pharmacophoric moiety (rimantadine). The ring size effect on anti-influenza A activity was investigated. Pyrrolidine 3 was the most potent anti-influenza ...