Synthesis, antiviral and cytotoxic activity of 6-bromo-2,3-disubstituted-4(3H)-quinazolinones

In the present study, a series of 6-bromo-2,3-disubstitued-4(3H)-quinazolinones was synthesized by condensation of 6-bromo-2-substituted-benzoxazin-4-one with trimethoprim, pyrimethamine and lamotrigine. The chemical structures of the synthesized compounds were confirmed by means of IR, (1)H-NMR and mass spectral and elemental analysis. The antiviral activity and cytotoxicity of the compounds were tested in E(6)SM (Herpes simplex-1 KOS, Herpes simplex-1 TK-KOS ACV, Herpes simplex-2 G, Vaccinia virus, Vesicular stomatitis virus, Parainfluenza-3 virus, Reovirus-1, Sindbis virus, Coxsackie virus B4 and Punta Toro virus) and HeLa cell culture (Vesicular stomatitis virus, Coxsackie virus B4 and Respiratory syncyticla virus). Investigation of anti-HIV activity was done against replication of HIV-1 (HTLV-III B LAI) in MT-4 cells. 6-Bromo-2-phenyl-3-[(4-amino-5-(4-chlorophenyl)-6-ethylpyrimidin-2-yl]-4(3H)-quinazolinone (4) exhibited the most potent antiviral activity with a MIC of 1.92 microg/ml against vaccinia virus in E(6)SM cell culture. The other compounds did not exhibit antiviral activity nor afford significant cytoprotection to the E(6)SM and HeLa cell culture when challenged with the viruses. The study implies that 4 may possess activity against Pox viruses including variola. In the anti-HIV study, 6-bromo-2-methyl-3-[(4-amino-5-(4-chlorophenyl)-6-ethylpyrimidin-2-yl]-4(3H)-quinazolinone (3) and 6-bromo-2-phenyl-3-[(4-amino-5-(4-chlorophenyl)-6-ethylpyrimidin-2-yl]-4(3H)-quinazolinone (4) exhibited the least cytotoxic concentration (0.424, 0.461 microg/ml) which is an index of the infective viability of mock infected MT-4 cells with HIV-1. None of the compounds exhibited significant anti-HIV activity.