Synthesis and anti-staphylococcal activity of new 4-diazopyrazole derivatives

Several new 4-diazopyrazole derivatives 6a-g and 9a-c were obtained by the reaction of 1-(R-substituted phenyl)-3-(1,3-dimethyl-1H-pyrazol-5-yl)ureas 5a-g and N-(1,3-dimethyl-1H-pyrazol-5-yl)-2-(R-substituted phenyl)acetamides 8a-c respectively with a sevenfold excess of nitrous acid in acetic acid solution. The compounds were assayed for their activity against the Staphylococcus aureus reference strains ATCC 25923, ATCC 29213 and ATCC 6538, as well as six veterinary strains. The best anti-staphylococcal profile was showed by [(R-substituted phenyl)acetyl](4-diazonio-1,3-dimethyl-1H-pyrazol-5-yl)azanides 9a,c. The compound 9c was also able at 3.1 µg mL-1 to inhibit of 45.7% the biofilm formation of the strains S.aureus ATCC 29213.