Abstract:

A series of bromo-o-hydroxyphenyl substituted hydrazones were synthesized by combining the molecule segment o-hydroxyphenyl with hydrazone derivatives according to antibacterial characteristics of o-hydroxydiphenyl ethers and hydrazone compounds. Seven 5-bromo-o-hydroxyphenyl substituted hydrazones were synthesized by using methyl salicylate as raw material, through bromination, hydrazination and condensation reactions, respectively.The structures of all the compounds have been confirmed by 1H NMR、IR、mass spectra and element analysis. The result of preliminary bioassay shows that the title compounds have obvious specificity antibacterial activities to different classificatory bacterium at 0.05%(mass concentration), and have 100% inhibitory ratio on Monilia albican and Bacillus subtilis. They will be a kind of potential antibacterial compounds in fungus and Gram-positive bacteria. The 5-bromo-o-hydroxyphenyl-3′,5′-dibromo-o-hydroxyphenyl hydrazone has the same antibacterial activities as triclosan. The analysis of structure activity show that antibacterial activities relate to the kind of Ar-ring and its substituent groups. The antibacterial activities were reduced by electron-donating groups, such as o-,p-OH、-OCH3, of Ar-ring, however, they were enhanced by the m-substituted halogen groups of Ar-ring.

Key words: 5-bromo-o-hydroxyphenyl aryl substitute hydrazone, methyl salicylate, synthesis, characterization, antibacterial activity