SYNTHESIS AND REACTIONS OF 6-ARYL-4-(3,5-DIMETHYLPYRAZOL-1-YL)-4,5-DIHYDRO-3(2H)-PYRIDAZINONES AND THE STUDY OF THEIR ANTIBACTERIAL AND MOLLUSCICIDAL ACTIVITIES

Beta-Aroylacrylic acid (1) react with 3,5-dimethylpyrazole to give alpha(4-substituted phenacyl) 3,5-dimethylpyrazole-1-acetic acids (2a,b). Reaction of (2) with hydrazines afford the corresponding 6-aryl-4-pyrazol-1-yl pyridazinones (3a-d). The behaviour of the pyridazinones, with benzenesulphonyl chloride and ethyl bromoacetate to give the N-substituted products (3e-f), with P2S5 to give the thione (4a), with POCl3 to give the chloropyridazine (6a), towards hydrazine hydrate, sodium azide, anthranilic acid and benzoylhydrazine to give (6b), (7), (8) and (9) respectively and with bromine acetic acid mixture has been studied. Dehydration of (2) yields the furanone derivative (11). The antibacterial screening reveals that compounds (3a) and (8) possess high activity, (2a) and (3e) possess moderate activity while the other compounds possess slight activity or inactive against gram-positive bacteria.