Synthesis, Spectroscopic Characterization, Crystal Structures and Antibacterial Activity of Benzohydrazones Derived from 4-Pyridinecarboxaldehyde with Various Benzohydrazides

Reaction of 4-pyridinecarboxaldehyde with 3-hydroxy-4-methoxybenzohydrazide, 4-bromobenzohydrazide and 4-dimethylaminobenzohydrazide, respectively in methanol afforded three new benzohydrazones. They are 3-hydroxy-4-methoxy-N’-(pyridin-4-ylmethylene)benzohydrazide (1), 4-bromo-N’-(pyridin-4-ylmethylene)benzohydrazide (2), and 4-(dimethylamino)-N’-(pyridin-4-ylmethylene)benzohydrazide (3). The compounds have been characterized by elemental analysis, 1H and 13C NMR and IR spectroscopy, as well as single crystal X-ray diffraction. The antibacterial activities of the compounds against E. coli, P. aeruginosa, B. subtilis, and S. aureus were investigated and gave interesting results.