A series of 4-amino-5-((4-chlorophenyl)diazenyl)-6-(alkylamino)-1-methylpyrimidin-2-one derivatives 7-16 were prepared by nucleophilic displacement of 6-chloro-pyrimidine 6 by various amines. 4-Amino-5-((aryl-4-yl)diazenyl)-6-aryl-1-methylpyrimidin-2-one analogs 19-27, as well as 4-amino-5-((aryl-[1,1'-biphenyl]-4-yl)diazenyl)-6-aryl-1-methylpyrimidin-2-one 29-31 and 4-amino-6-aryl-1-methylpyrimidin-2-one 34-34, were synthesized via Suzuki cross-coupling reaction, using Pd(PPh3)4 as a catalyst and arylboronic acids as reagents. All compounds were evaluated for their antiviral activity against the replication of HIV-1 and HIV-2 in MT-4. Compounds 6, 16, 27, and 29 showed a 50% effective concentration of >2.15, >3.03, >2.29, and >1.63 μM, respectively, but no selectivity was observed (selectivity index < 1). Two of the newly synthesized pyrimidines 12 and 29 exhibited moderate kinesin Eg5 inhibition.