Synthesis and antimicrobial activity of some new triazino-, triazolo-, and pyrazolopyridazine derivatives

The reaction of 3-hydrazino-4,5,6-triphenylpyridazine with phenacyl bromide afforded triazolopyridazine, while the reaction with different aldehydes gave the corresponding 3-arylidene hydrazinopyridazine derivatives which, on reaction with Br(2)/Na(2)CO(3), gave the corresponding triazinopyridazines. Also, fusion with ethyl acetoacetate, ethyl benzoylacetate, diethyl malonate, or ethyl phenylacetoacetate gave the corresponding pyrazolo- and triazinopyridazine derivatives. The antimicrobial activity of some of the new compounds has been discussed.