3-Hydrazinoquinoxalin-2(1H)-one was prepared from quinoxaline-2,3-dione and subsequently used for the synthesis of some potentially biologically active 3-(pyrazol-1-yl)quinoxalin-2(1H)-one derivatives. While 3-(3,5-dimethylpyrazol1-yl)quinoxalin-2(1H)-one showed a comparative effect with
streptomycin, 3-(5-oxo-3-phenyl-4,5-di- hydropyrazol 1-yl)quinoxalin-2(1H)-one was found to be the most active with an MIC value of 7.8 μg/ml
