Abstract
4-(2-(4-Halophenyl)hydrazinyl)-6-phenylpyridazin-3(2H)-ones 1a,b were prepared and treated with phosphorus oxychloride, phosphorus pentasulphide and ethyl chloroformate to give the corresponding chloropyridazine, pyridazinethione, oxazolopyridazine derivatives 2–4, respectively. Compound 2 reacted with hydrazine hydrate to afford hydrazinylpyridazine 7. The reaction of 4-(2-(4-chlorophenyl)hydrazinyl)-3-hydrazinyl-6-phenylpyridazine (7) with acetic anhydride, p-chlorobenzaldehyde and carbon disulphide gave the corresponding pyridazinotriazine derivatives 8–10. On the other hand, 5-(4-chlorophenylamino)-7-(3,5-dimethoxybenzylidene)-3-phenyl-5H-pyridazino[3,4-b][1,4]thiazin-6(7H)-one (11) was prepared directly from the reaction of compound 3 with chloroacetic acid in presence of p-chlorobenzaldehyde. Compound 11 reacted with nitrogen nucleophiles (hydroxylamine hydrochloride, hydrazine hydrate) and active methylene group-containing reagents (malononitrile, ethyl cyanoacetate) to afford the corresponding fused compounds 12–15, respectively. Pharmacological screening for antiviral activity against hepatitis A virus (HAV) was performed for the new compounds. 4-(4-Chlorophenylamino)-6-phenyl-1,2-dihydropyridazino[4,3-e][1,2,4]triazine-3(4H)-thione (10) showed the highest effect against HAV.
Highlights
Heterocyclic compounds compounds based based on the pyridazine backbone backbone have been cited as significant biologically active pharmacophores in the field of medicinal chemistry, chemistry, providing a wide range of safe and effective drugs [1,2,3,4,5,6]
We report the synthesis of some new heterocyclic compounds containing pyridazine moieties and the study of their anti-viral activities compared to amentadine as positive control
The incorporation of substituents in the pyridazine ring or as a fused component often leads to incredibly diverse biological activity
Summary
Heterocyclic compounds compounds based based on the pyridazine backbone backbone have been cited as significant biologically active pharmacophores in the field of medicinal chemistry, chemistry, providing a wide range of safe and effective drugs [1,2,3,4,5,6]. The pyridazine ring is a part of the structures of some therapeutic agents. The pyridazine ring is available on the market like cadralazine [7,8], minaprine minaprine [9,10,11],. [9,10,11], hydralazine hydralazine [12,13],. [12,13], pipofezine pipofezine [14],.
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