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 PCl 5-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. © 2005 NRC Canada.