SYNTHESIS AND REACTIONS OF SOME NEW PYRIDAZINONES

3-(p-Ethoxybenzoyl)acrylic acid (1) reacts with 3-methyl-1-phenyl-2-pyrazolin-5-one to give an addition compound 2. The condensation of 2 with hydrazine hydrate affords 4,5-dihydro-3(2H)-pyridazinone (3a). Reaction of 3a with dimethyl sulfate, diethyl sulfate, ethyl bromoacetate, POCl3, and P2S5 gave the N-substituted pyridazinones 3b-d, a dichloro derivative 5a, and a dithione 7. The behavior of the dichloro and the dithione derivatives was studied toward different reagents. The in vitro antibacterial screening reveals moderate activity against Gram-positive for compounds 3a and 3c while 4 and 7 are inactive.