# Novel Quinazolinones Active against Multidrug‐Resistant Mycobacterium Tuberculosis: Synthesis, Antimicrobial Evaluation, and in Silico Exploration of Penicillin‐Binding Protein 1A as a Potential Target

## TL;DR

New quinazolinone compounds show strong activity against drug-resistant tuberculosis and may target a novel site in a key bacterial protein.

## Contribution

Discovery of quinazolinone derivatives with potent activity against drug-resistant Mycobacterium tuberculosis and a novel allosteric binding site in PBP 1A.

## Key findings

- 53 quinazolinone compounds synthesized and tested, with MICs as low as 6.25 μg mL−1 against M. tuberculosis.
- Molecular docking and dynamics reveal stable binding to PonA1 with interactions involving ARG399 and ASP474.
- Compounds show preserved activity against drug-resistant strains and suggest a non-β-lactam inhibition mechanism.

## Abstract

Quinazolinone derivatives have emerged as promising scaffolds in antimicrobial drug discovery. This work focuses on the design, synthesis, and evaluation of novel quinazolinone‐based compounds and predicts their potential to interact with mycobacterial penicillin‐binding proteins (PBPs). Relying on established structure–activity relationships of antibacterial quinazolinones, a total of 53 compounds belonging to three different structural types are synthesized and biologically evaluated for antimycobacterial, antibacterial, and antifungal activities. Biological evaluations reveal selective efficacy against Mycobacterium tuberculosis with minimum inhibitory concentrations (MICs) as low as 6.25 μg mL−1 for some derivatives, and this activity is preserved against drug‐resistant strains. Molecular docking studies suggest a potential allosteric binding site in mycobacterial PBP 1A (PonA1, UniProt ID: P71707), and subsequential molecular dynamics confirm stable binding with key stabilizing interaction between the carbonyl oxygen of the quinazolinone and either ARG399 or ASP474. These findings suggest quinazolinone derivatives as viable candidates for further development as non‐β‐lactam PBP inhibitors, addressing the urgent need for new antitubercular therapies.

Quinazolinone‐based compounds emerge as potent antimycobacterial agents, showing low minimum inhibitory concentrations against drug‐resistant Mycobacterium tuberculosis. Molecular modeling uncovers a novel allosteric site in PonA1 targeted by these derivatives. Stable interactions with key residues suggest a non‐β‐lactam inhibition mechanism, positioning quinazolinones as powerful candidates in the fight against persistent tuberculosis.© 2025 WILEY‐VCH GmbH