Design, synthesis and molecular docking studies of quinazolin-4-ones linked to 1,2,3-triazol hybrids as Mycobacterium tuberculosis H37Rv inhibitors besides antimicrobial activity

Abstract

Quinazolin-4-ones linked to 1,2,3-triazol (10) were identified as inhibitors of the bisphosphonate BPH-700 transcriptional factor from a high throughput screen. A series of 1,4-disubstituted triazoles (10a–j) were synthesized by the Cu-catalyzed azide-alkyne cyclo addition of 5-methoxy-2-nitro-4-(prop-2-yn-1-yloxy) benzamide (6) with various substituted azido benzenes (7) in the presence of CuSO4 under aerobic conditions followed by click reaction with substituted aldehydes. The target compounds were screened for antitubercular activity against Mycobacterium tuberculosis H37Rv by Broth micro dilution method using Lowenstein Jensen medium (LJ) (MIC < 9 μg/mL). Majority of the compounds 10b, 10d, 10e, 10i and 10j displayed good antitubercular activity with MIC 7–11 μg/mL. Further, 10e exhibited a promising inhibition with MIC 7 μg/mL, compared to the reference drug Rifampicin. Docking studies have been performed to understand the interactions between the synthesized compounds and the active site of pantothenate synthetase Mycobacterium tuberculosis H37Rv organism. The study revealed that the target compounds showed good affinity toward the protein when compared to the standard drug Pefloxacin. Further, 10b was found to interact with three amino acids, viz., Gln92, Arg200, Ser196, as evidenced by the large interaction energy (ΔG = −8.16 kcal/mol). Besides the above, the synthesized quinazolinone triazoles 10a–j were evaluated for their antibacterial activities against a panel of Gram +ve and Gram –ve bacteria. Among them 10a, 10e, 10 h and 10j showed promising broad spectrum antibacterial activity with inhibition in the range of 19–33-mm diameter of inhibition zone (DIZ).