Design, Synthesis, and Structure–Activity Relationships of Novel N-Substituted-5-phenyl-[1,2,4]triazolo[1,5-c]quinazolin-2-amine for Their Anti-HIV and Antibacterial Activities.

A new series of N-substituted-5-phenyl-[1,2,4]triazolo[1,5-c]quinazolin-2-amine (XIa–o) were synthesized by the nucleophilic substitution reaction of 4-(2-(methylthio)-5-phenyl-[1,2,4]triazolo quinazoline (X) with different aryl amines. The starting material 2-(methylthio)-5-phenyl-[1,2,4]triazolo quinazoline (X) was synthesized from anthranilic acid. All synthesized compounds were screened for their antitubercular, anti-HIV and antibacterial activity against selective gram-positive and gram-negative bacteria by agar dilution method. Among the series, compound N-(4-nitrophenyl)-5-phenyl-[1,2,4]triazolo[1,5-c]-quinazolin-2-amine (IXi) and N-(4-chlorophenyl)-5-phenyl-[1,2,4]triazolo[1,5-c]-quinazolin-2-amine (IXk) showed the most potent activity against E. coli, P. aeruginosa and S. epidermidis with the MIC of 3 µg/mL. The compound (IXi) exhibited the antitubercular activity at 6.25 µg/mL and anti-HIV activity at 7.15 µg/mL, respectively, against HIV1 and HIV2. It can be offered the potential for further optimization and development to new antitubercular and anti-HIV agents. The results obtained from this study confirm that the synthesized and biologically evaluated triazolo quinazolines showed promising antimicrobial, antitubercular and anti-HIV activities. [ABSTRACT FROM AUTHOR]