Design, synthesis and in vitro antimicrobial evaluation of novel Imidazo[1,2-a]pyridine and imidazo[2,1-b][1,3]benzothiazole motifs

New antimicrobial agents, imidazo[1,2-a]pyridine and imidazo[2,1-b][1,3]benzothiazole, have been synthesized. Their antimicrobial activities were conducted against various Gram-positive, Gram-negative bacteria and fungi. Compounds 6c, 7a, 10b, 11a, 12b, 14a, 14b, 15a and 15b, exerted strong inhibition of the investigated bacterial and fungal strains compared to control antibiotics amoxicillin and cefixime and the antifungal agent fluconazole. Results from this study showed that the nature of the substituents on the armed aryl groups determines the extent of the activity of the fused imidazopyridine and/or imidazobenzothiazole derivatives. Preliminary structure–activity observations revealed that bromo-fluoro substituents enhanced the antimicrobial activity significantly compared to other substituents.

Graphical abstractNew antimicrobial agents, imidazo[1,2-a]pyridine and imidazo[2,1-b][1,3]benzothiazole derivatives have been synthesized and biologically evaluated as antimicrobial agents against various Gram-positive, Gram-negative and fungus strains.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of novel antimicrobial leads with potent activity against various Gram-negative, Gram-positive bacterial and fungal strains. ► Imidazo[1,2-a]pyridine and imidazo[2,1-b][1,3]benzothiazole derivatives have been synthesized using Groebke–Blackburn 3CR protocol. ► A reversed chemical genetics approach will allow us to understand the biochemical mechanism of action of these novel scaffolds.