Synthesis, Molecular Docking, and Biological Activity of Antimetabolites Based on Uracils and 5-Substituted 2,6-Dimethylpyrimidin-4(3H)-ones

5-Substituted 2,4-dimethyl-1,6-dihydropyrimidin-6-ones reacted with aromatic aldehydes to give 5-substituted 2-[( E )-2-arylethenyl]pyrimidin-6-ones, and the reaction of 5-(4-fluorobenzyl)-2,6-dimethylpyrimi­din-4(3 H )-one with 4-fluorobenzaldehyde produced 5-(4-fluorobenzyl)-2,6-bis[( E )-2-(4-fluorophenyl)ethenyl]­pyrimidin-4(3 H )-one. Uracil and 5-fluorouracil were alkylated with 2-(chloromethyl)-4-methoxybenzaldehyde, and the resulting 3-[2,4-dioxo- and 5-fluoro-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl)methyl]-4-methoxy­benz­aldehydes were condensed with 5-substituted 2,4-dimethyl-1,6-dihydropyrimidin-6-ones to obtain 1-(5-{( E )-2-[5-(butyl, arylmethyl)-4-methyl-6-oxo-1,6-dihydropyrimidin-2-yl]ethenyl}-2-methoxybenzyl)­uracil, -5-fluorouracil, and -5-bromouracil. The synthesized compounds were evaluated for their antibacterial, antitumor, and anti-monoaminoxidase activities, and their molecular docking to some biological targets was performed.