A series of novel 2/3-substituted sulfur-5-o-hydroxyphenyl zoles compounds 5a～7d were designed by means of combining segments o-hydroxyphenyl and azole heterocycles, according to the superpostion principle of reinforcement of biological activities. Salicylic hydrazides were synthesized by methylsalicylate with hydrazinehydrate in ethanol, then, reacted with carbon disulfide or ammonium thiocyanate and hydrochloride to obtain 5-o-hydroxyphenyl-1,3,4-oxadiazole-2-thiones (2), 5-o-hydroxyphenyl-1,3,4- thiadia-zole-2-thiones (3) and 5-o-hydroxyphenyl-4H-1,2,4-triazole-3-thiones (4). Finally, under alkaline conditions, the target compounds were obtained by nucleophilic substi-tution reaction with the halogenated acetophenone. The structures of final products were determined by ¹HNMR, IR spectra and element analysis. The result of preliminary bioassay showed that the title compounds had 92% inhibitory rate against Monilia albican and Escherichia coli at 0.01% mass concentration and a favorable extent of antibacterial activities against Staphylococcus aureus (over 82%). This kind of compounds have broad spectrum antibacterial activities against different bacteria and they would be a good choice of antibacterial compounds against fungi and gram-negative bacte-ria. The analysis of structure-activity relationship showed that the antibacterial activities of title compounds were enhanced by the halogen groups, such as Cl and Br, but reduced by electron-donating groups of the phenylethanone rings, such as CH₃.

Key words: 2-substituted sulfur-5-o-hydroxyphenyl-1,3,4-oxadiazole, 2-substituted sulfur-5-o-hydroxy- phenyl-1,3,4-thiadiazole, 3-substituted sulfur-5-o-hydroxyphenyl-1,2,4-triazole, characteriza-tion, antibacte- rial activity