Novel arylhydrazones of methylene active compounds – 3-(2-(1-ethoxy-1,3-dioxobutan-2-ylidene)hydrazinyl)-2-hydroxy-5-nitrobenzenesulfonic acid (1), 2-(2-(2-hydroxy-4-nitrophenyl)hydrazono)-2 H-indene-1,3-dione (2), 5-chloro-2-hydroxy-3-(2-(4,4,4-trifluoro-1,3-dioxo-1-(thiophen-2-yl)butan-2-ylidene)hydrazinyl) benzenesulfonic acid (3), 5-chloro-2-hydroxy-3-(2-(2,4,6-trioxo-tetrahydropyrimidin-5(6 H)-ylidene)-hydrazinyl)benzenesulfonic acid (4), 5-(2-(2-hydroxyphenyl)hydrazono)pyrimidine-2,4,6(1 H,3 H,5 H)-trione (5), 4-hydroxy-5-(2-(2,4,6-trioxo-tetrahydro-pyrimidin-5(6 H)-ylidene)hydrazinyl)benzene-1,3-disulfonic acid (6), 5-(2-(2-hydroxy-4-nitrophenyl)hydrazono)pyrimidine-2,4,6(1 H,3 H,5 H)-trione (7) and 5-chloro-3-(2-(4,4-dimethyl-2,6-dioxocyclohexylidene)hydrazinyl)-2-hydroxybenzenesulfonic acid (8) have been synthesized by a reaction between the corresponding methylene active compounds and aryldiazonium salts, and characterized by IR, 1 H and 13 C NMR spectroscopies and element analysis. The collected information confirms that 2, and 4 – 8 exist in DMSO solution in hydrazone form, being stabilized by an intramolecular hydrogen bond, while 1 and 3 exist in mixed enol-azo and hydrazo tautomeric forms. The antimicrobial activity of 1 – 8, as well as that of known analogs 5-(2-(4,4-dimethyl-2,6-dioxocyclohexylidene)hydrazinyl)-4-hydroxybenzene-1,3-disulfonic acid (9), 2-(2-sulfophenylhydrazo)malononitrile (10), 2-(2-carboxyphenylhydrazo) malononitrile (11), 2-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)phenylarsonic acid (12) and 5-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)-2,3-dihydrophthalazine-1,4-dione (13), have been studied. It was found that arylhydrazones of barbituric acid are more active than other methylene active compounds. A whole-cell bacterial luminescence biosensor method was used to detect the antimicrobial activity of the synthesized compounds. The results show that compounds 5 and 9 effectively inhibit the luminescence of Staphylococcus aureus at a minimum inhibitory concentration (MIC50) of 10 and 9 μg/ml, respectively. For Staphylococcus epidermidis, compound 11 showed the most potent activity with MIC50 of 17 μg/mL; for Pseudomonas aeruginosa, compounds 11 showed the most potent activity at MIC50 of 10 μg/mL. Observed results have been verified to be statistically significant using the two-tailed test.
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