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

Abstract

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.

Synthesis of Some Novel Norbornene‐Fused Pyridazines as Potent Inhibitors of Carbonic Anhydrase and Acetylcholinesterase

“…) . Several compounds derived from pyridazines scaffold have been reported to possess a wide spectrum of biological activity such as the antidepressant, dopaminergic drug, monoamine oxidase inhibitor, anticonvulsant, GABA antagonist, muscarinic M1 partial agonist, and acetylcholinesterase (AChE) inhibitor . The chemistry of pyridazines is also dominantly useful as a pioneer for the preparation of other heterocycles, pi‐conjugated organic materials, and self‐assembled supramolecular architectures .…”

Facile Synthesis of New [1,2,4]Triazolo[4,3‐b]pyridazine

“…Treatment of these compounds with hydrazine hydrochloride gave the 4-(4-substituted phenyl)1,2,3,6-tetrahydro-3,6-pyridazinediones 3a-c. Chlorination of the latter compounds with phosphoryl chloride in the presence of N,N-diethyl aniline afforded the 3,6-dicholoro-4-(4-substitutedphenyl)pyridazines 4a-c in high yields. Compounds 4a-c were subsequently converted to their hydrazine derivatives 5a-c by selective displacement of six-chlorine atom [18] with hydrazine hydrate in ethanol at reflux condition (Scheme 1).…”

“…Chlorination of the latter compounds with phosphoryl chloride in the presence of N , N ‐diethyl aniline afforded the 3,6‐dicholoro‐4‐(4‐substitutedphenyl)pyridazines 4a , 4b , 4c in high yields. Compounds 4a , 4b , 4c were subsequently converted to their hydrazine derivatives 5a , 5b , 5c by selective displacement of six‐chlorine atom with hydrazine hydrate in ethanol at reflux condition (Scheme ).…”

Useful Precursors for Synthesis of Some New Azolo[3,4‐d]pyridiazines, Azolo[1,5‐a]pyrimidines, Azolo[5,1‐c]triazines, Pyrazoles, and Benzo[b][l,4]diazepine

“…Also, several pyrazolotriazines and triazolotriazines, as adenine analogues, were used as antagonists, antischistosomal, and antitumor agents . Pyridazine compounds have been reported to possess varied biological agents such as antimicrobial , antihypertensive , anticancer , anti‐inflammatory , and antifungal activities . Also, pyrazole derivatives are important intermediates in organic synthesis and possess a range of interesting biological and antimicrobial properties .…”