Synthesis of some heterocyclic systems of anticipated biological activities via 6-aryl-4-pyrazol-1-yl-pyridazin-3-one

Abstract

6-Aryl-4-pyrazol-1-yl-pyridazin-3-one (1) reacted with a PCl5–POCl3 mixture to give the 3-chloropyridazine derivative 3. Reaction of 3 with 2-hydroxybenzoylhydrazide and semicarbazide hydrochloride afforded 4 and 5. Reaction of 1 with ethyl chloroacetate gave 8. Reaction of 8 with hydrazine hydrate yielded the hydrazide 9. The hydrazide 9 condensed with the acetylenic ketones and esters 10a–10d and acetylacetone to give the adducts 11a, 11b, 12, 13, and 14. Reacting 1 with formaldehyde and piperidine, morpholine, or piperazine, 3-bromopropanoic acid, acetic anhydride, p-toluenesulphonyl chloride, succinyl chloride, oxalyl chloride, ethanolamine, or ethyl chloroacetate gave the adducts 15–22. The structures of all newly synthesized compounds were evidenced from their spectral and microanalytical data. Key words: 6-aryl-4-pyrazol-1-yl-pyridazinone derivative, 6-aryl-3-chloropyridazine derivative, 3,6-diaryl-1,2,4-triazino[4,3-b]pyridazine derivative, 6-aryl-3-ethoxycarbonylmethoxypyridazine derivative, 6-aryl-3-(ω-benzoylacetophenone)hydrazinocarbonylmethoxypyridazine.