Abstract
3,5-Bis(4-chlorobenzylidene)-1-ethylpiperidin-4-one (1b) was condensed with malononitrile or cyanothioacetamide to yield pyranopyridine 2 and thiopyridopyridine 3b, respectively. Treatment of compound 3b with methyl iodide or ethyl chloroacetate in the presence of a base catalyst gave the corresponding compounds 4 and 5. Compound 3b was reacted with 2-chloro-N-arylacetamide derivatives to yield compounds 7a,b, which were reacted with benzoyl chloride or sodium nitrite to give the corresponding tetracyclic compounds 8a,b and 9a,b, respectively. Compound 2 was treated with acetic anhydride or formic acid to yield the corresponding N-acetylpyranopyridine 10 and pyranopyrimidine 11. Treatment of compound 2 with triethyl ortho-formate gave compound 12, which was cyclized with hydrazine hydrate to give N-aminopyrimidine 13. Some of the synthesized compounds showed high antiarrhythmic activities comparable with Procaine amide and Lidocaine as positive controls.