Synthesis and In Vitro Anti-HIV Activity of Some New Schiff Base Ligands Derived from 5-Amino-4-phenyl-4H-1,2,4-triazole-3-thiol and Their Metal Complexes

New Schiff base ligands (6-9) derived from 5-amino-4-phenyl-4H-1,2,4-triazole-3- thiol 1 and substituted benzaldehydes (2-5) as well as their metal complexes with Cu(II), Fe(II), Au(III), and Mn(II) (12-17) have been synthesized. A new benzothiazole derivative (11) was prepared from coupling of 7 with N-(benzothiazol-2-yl)-2-chloroacetamide 10. Their spectral properties were investigated. The newly designed and synthesized Schiff base ligands and the metal complexes were assayed for anti-HIV-1 and HIV-2 activity by examination of their inhibition of HIV-induced cytopathogenicity in MT-4 cells. Compounds 11 and 16 were found to be the most active inhibitors in cell culture (EC(50) = 12.2 mu g/mL (SI = 4) and > 2.11 mu g/mL (SI = > 1), respectively) against HIV-1, whereas 11 showed inhibition against HIV-2 of EC(50) > 10.2 mu g/mL with SI = 9, which provided a good lead for further optimization.