Synthesis and antibacterial activity in vitro of 2-benzylthioimidazo[1,2-a]pyridine derivatives against pathogenic bacterial

To explore the antibacterial activity, a set of new 2-thiobenzyl-3-nitro-imidazo[1,2-a]pyridine derivatives were synthesized (9a–h) and characterized by NMR 1H, 13C and high-resolution mass (HRMS). These compounds were obtained by interaction between the 3-nitro-imidazo[1,2-a]pyridine isothiouronium salt (7) with benzyl chloride or bromide (8) in the presence of sodium hydroxide (NaOH). Eight (9a–h) of them were evaluated in vitro on the positive gram bacterium (S. aureus ATCC 29213) and two others negative gram bacteria (P. aeruginosa ATCC 27853 and P. aeruginosa 933 C/21) by methods diffusion in solid medium and liquid macrodilution. Five among the eight compounds (9a, 9d, 9h, 9f and 9g) showed significant antibacterial activity on P. aeruginosa ATCC 27853 and P. aeruginosa 933 C/21with MIC between 7.81 and 250 µg/mL. All compounds were inactive on S. aureus. The compounds 9a and 9g were more potent on the two strains of P. aeruginosa ATCC 27853.