Synthesis, Molecular Docking Study, and Effect on the Methylation of Tumor DNA of Benzo[4′,5′]imidazo[2′,1′:6,1]pyrido[2,3-d]pyrimidines Functionalized by Aromatic Groups and Azines

6-Benzyl-4-styrylbenzo[4′,5′]imidazo[2′,1′:6,1]pyrido[2,3-d]pyrimidines and their conjugates with uracil, 5-fluorouracil, and 6-azauracile were synthesized. In addition to the previous findings, it was found that the reaction of 4-methyl-2-phenyl-5,6-dihydrobenzo[4′,5′]imidazo[2′,1′:6,1]pyrido[2,3-d]pyrimidine with aromatic aldehydes in acetic anhydride, depending on the nucleophilicity of the aldehyde carbonyl group, involved both C⁶H₂ methylene group at the α-position with respect to the benzimidazole fragment and the 4-methyl group. The results of molecular docking study of the synthesized compounds and their effect on the methylation of tumor DNA are presented.