title: Enaminones as building blocks in heterocyclic syntheses: reinvestigating the product structures of enaminones with malononitrile. A novel route to 6-substituted-3-oxo-2,3-dihydropyridazine-4-carboxylic acids.
abstract: The reported structures of reaction products of enaminones with malononitrile in ethanolic piperidine are revised. A novel route to 2,3-dihydropyridazine-4-carboxylic acids 4a-c via reactions of 2-cyano-5-(dimethylamino)-5-arylpenta-2,4-dienamides 8a-c with nitrous acid or with benzenediazonium chloride is reported. Compounds 8a-c are converted to 1,2-dihydropyridine-3-carboxylic acid and 1,2-dihydropyridine-3-carbonitrile derivatives upon reflux in EtOH/ HCl and in AcOH.
authors.affiliation: Applied Science Department, College of Technological Studies, Public Authority for Applied Education and Training, Safat, Kuwait.
authors.forename: Abdul-aziz
authors.initials: AA
authors.lastname: Alnajjar
authors.forename: Mervat Mohammed
authors.initials: MM
authors.lastname: Abdelkhalik
authors.forename: Amal
authors.initials: A
authors.lastname: Al-Enezi
authors.forename: Mohamed Hilmy
authors.initials: MH
authors.lastname: Elnagdi
mesh_terms: D002264:Carboxylic Acids / Q000138:chemical synthesis* / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D009570:Nitriles / Q000737:chemistry*; D010880:Piperidines / Q000737:chemistry; D011724:Pyridazines / Q000737:chemistry*
chemical_list: C534560:3-oxo-6-(thiophene-2-carbonyl)- 2,3-dihydropyridazine-4-carboxylic acid; C534559:6-(furan-2-carbonyl)-3-oxo-2,3-dihydropyridazine-4-carboxylic acid; C534558:6-benzoyl-3-oxo-2,3-dihydropyridazine-4-carboxylic acid; D002264:Carboxylic Acids; D009570:Nitriles; D010880:Piperidines; D011724:Pyridazines; D000431:Ethanol; C032727:piperidine; C000945:dicyanmethane