Synthesis and antimicrobial screening of novel series of imidazo-[1,2-a]pyridine derivatives

Abstract

In an attempt to find new bio-active molecules, a series of mannich bases N,N-dimethyl-1-(7-methyl-2-(aryl)imidazo[1,2-a]pyridin-3-yl)methanamines 4a–l were synthesized by mannich reaction of 7-methyl-2-(aryl)imidazo-[1,2-a]pyridines 3a–l with paraformaldehyde and N,N-dimethyl amine. Compounds 3a–l were prepared from reaction between different substituted 2-bromo-1-(aryl)ethanones 2a–l and 4-methylpyridin-2-amine 1. Structures of these compounds were confirmed by IR, 1H NMR, 13C NMR, and mass spectral data. Antimicrobial screening of title compounds 3a–l was examined against Gram-positive bacteria (Staphylococcus aureus, Streptococcus pyogenes), Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), and fungi (Candida albicans, Aspergillus niger, Aspergillus clavatus) using serial broth dilution method. Some derivatives bearing halogen group was found to be equipotent or more potent than commercial drugs, against most of the employed strains, as evident from the screening data.