Abstract
Novel 5-amino-1-(6-phenyl-pyridazin-3-yl)-1H-pyrazole-4-carboxylic acid ethyl ester (2) was formed using (6-phenyl-pyridazin-3-yl)-hydrazine (1) and ethyl(ethoxymethylene)cyanoacetate. The -enaminoester derivative 2 was in turn used as precursor for the preparation of 1-(6-phenyl-pyridazin-3-yl)-pyrazoles (3, 4, 7, 8, 9, 10, 11, 12, 15, 16), 1-(6-phenyl-pyridazin-3-yl)-pyrazolo[3,4-d]pyrimidines (5, 6, 14) and 1-(6-phenyl-pyridazin-3-yl)-pyrazolo[3,4-d][1,2,3]triazine (13). The in vitroantimicrobial activity of the synthesized compounds was evaluated by measuring the inhibition zone diameters where some of them showed potent antimicrobial activity in compared with well-known drugs (standards).