Synthesis, crystal structure, optical properties and antibacterial evaluation of novel imidazo[1, 5-a]pyridine derivatives bearing a hydrazone moiety.

A series of novel imidazo[1,5-a]pyridine-hydrazone derivatives were synthesized and characterized by infrared spectroscopy (IR), 1H NMR, 13C NMR and high resolution mass spectrometer (HRMS). Typically, the spatial structure of compound 3j was determined using X-ray diffraction analysis. The UV-vis absorption and fluorescence spectral characteristics of the compounds in dichloromethane and acetonitrile were investigated. Absorption peaks could be observed in the wavelength range 290-450 nm. It can also be seen that they display very similar maximum emission. The group attached to hydrazone hardly influenced the maximum emission. Furthermore, all the compounds were evaluated for antibacterial activity and were found to be more effective against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa and Shigella compared with chloramphenicol.