Synthesis of Novel Derivatives of 4-Amino-3-(2-Furyl)-5-Mercapto-1,2,4-Triazole as Potential HIV-1 NNRTIs

A series of 5-alkylthio (2a-d), 4-arylideneamino (3a-d) and 4-arylideneamino-5-alkylthio derivatives (4a-f) of 4-amino-3-(2-furyl)-5-mercapto-1,2,4-triazole (1) were synthesized by alkylation of the parent compound with alkyl halides and condensation with aldehydes, respectively. Sulfanyl dimers 5a-d and 4-iminomethyl dimer 6 were correspondingly prepared by reaction with alkane dibromides and 1,4-diformylbenzene. Mannich base 7 was also synthesized by aminomethylation of the 3-sulfanyltriazole 1 at the N1 position. The newly designed and synthesized substituted s-triazole derivatives were assayed for anti-HIV-1 activity by examination of their inhibition of HIV-1-induced cytopathogenicity in MT-4 cells and by determination of their inhibitory effect on HIV-1 reverse transcriptase. Compound 4e was found to be the most active inhibitor against HIV-1 replication in cell culture (EC50 = 12 microM) and against HIV-1 reverse transcriptase (IC50 = 43.5 microM), which provided a good lead for further optimization.