Synthesis and some reactions of 4-aroyl-6-arlypridazine-3- [2H] ones

ABSTRACT

4-aroyl -6 -p- tolylpyridazine -3 [2H] ones [2a and b] were prepared by the oxidation of the corresponding 4- benzyl derivatives [3a and b] using sodium dichromate in glacial acetic acid. Compounds [2a and b] underwent normal condensation reactions of ketones with hydrazine hydrate and 2,4- dinitrophenyl- hydrazine to give the corresponding hydrazones [5a-c] and with hydroxylamine hydrochloride to give the oximes [5d and e]. 2a and b] reacted with dimethyl sulphate to give 6a and b. The reaction of [2a and b] with formaldehyde in the presence of secondary amines gave the Mannich bases [8a-d]. The pyridazinones [2a and b] underwent a Michael type addition to acrylonitrile to give [9a and b], respectively. The alkaline hydrolysis of [9b] affected complete cleavage of the cyanoethyl group yielding the aroylpyridazinone [2b]