A series of 1-(2-hydroxybenzoyl)-3-methyl-4-substituted phenylhydrazono-pyrazolones (4a～4f) and their intermediates 3a～3f were designed and synthesized by combining o-hydroxyl pheny, pyrazoleone and phenylhydrazone groups, according to the superposition principle of biological activities. Eight compounds and antibacterial-activity of all compounds have not been reported so far. Substituted anilines were diazotized and subsequently reacted with ethylacetoacetate, then condensed with salicylic hydrazide to obtain 3a～3f. The title compounds were acquired by intramolecular cyclization reaction of 3a～3f. The structures of all compounds were confirmed by IR, ¹H NMR spectra and elemental analysis. The results of preliminary bioassay showed that the inhibitory rates against Escherichia coli of compounds 3b, 3c were high to 100% at 0.01% mass concentration, which displayed excellent antibacterial activities; and the inhibitory rates against Monilia albican and Staphlococcus aureus were over 70%, which exhibited a certain extent antibacterial activities. The inhibitory rates against Moniliaalbican and Escherichia coli of the compounds 4a～4f reached to 100% at 0.01% mass concentration, which displayed excellent antibacterial activities. The inhibitory rates against Staphlococcus aureus were over 78%, which exhibited a certain extent antibacterial activities. Comparing with those of 3a～3f, the inhibitory rates of the compounds 4a～4f were enhanced.

Key words: 2-phenylhydrazono-3-(o-hydroxybenzoylhydrazono)-ethyl butanoate, 1-(o-hydroxybenzoyl)-4- substituted phenylhydrazono-pyrazolone, synthesis, characterization, anti-bacterial-activity