Design, Synthesis and Computational Studies of New Benzothiazole Substituted Quinazolines as Potential Antimicrobial Agents

Some novel N-(benzo[d]thiazol-2-yl)-2-((4-(4-(m-tolyloxy)quinazolin-2yl)phenyl)amino)acetamides analogs (7a-j) have been synthesized. The synthetic approach exploits a consolidated protocol based on Suzuki coupling reaction on quinazoline ring. The analogs were tested for microbiological activity against eight bacteria (Staphylococcus aureus MTCC 96, Bacillus cereus MTCC 619, Escherichia coli MTCC 739, Pseudomonas aeruginosa MTCC 741, Klebsiella pneumoniae MTCC 109, Salmonella typhi MTCC 733, Proteus vulgaris MTCC 1771 and Shigella flexneri MTCC 1457) and four fungi (Aspergillus niger MTCC 282, Aspergillus fumigatus MTCC 343, Aspergillus clavatus MTCC 1323, and Candida albicans MTCC 183). Some of the synthesized analogs have demonstrated excellent antimicrobial activity (MICs: 3.12-25 mu g/mL) as compared with the standards (MICs: 6.25-25 mu g/mL). Density Functional Theory (DFT) calculations at the B3LYP/6-31G(d,p) level were performed to predict the molecular structure and electronic properties of the analogs. Further, the binding orientations of the potent analogs were validated by molecular docking studies.