Design, synthesis and antimycobacterial activity of novel imidazo[1,2-a]pyridine-3-carboxamide derivatives

We report herein the design and synthesis of "novel imidazo [1,2-a]pyridine-3-carboxamides (IPAs)" bearing a variety of different linkers, based on the structure of IMB-1402 discovered in our lab. Results reveal that 2,6-dimethyl-N-[2-(phenylamino)ethyl] IPAs with an electron-donating group on the benzene ring as a potent scaffold. Compounds 26g and 26h have considerable activity (MIC: 0.041-2.64 μM) against drug-sensitive/resistant MTB strains, and they have acceptable safety indices against MTB H37Rv with the SI values of 4395 and 1405, respectively. Moreover, N-[2-(piperazin-1-yl)ethyl] moiety was also identified as a potentially alternative linker (compound 31), opening a new direction for further SAR studies.