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

Abdul-aziz Alnajjar; Mervat Mohammed Abdelkhalik; Amal Al-Enezi; Mohamed Hilmy Elnagdi

doi:10.3390/molecules14010068

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

Molecules. 2008 Dec 29;14(1):68-77. doi: 10.3390/molecules14010068.

Authors

Abdul-aziz Alnajjar¹, Mervat Mohammed Abdelkhalik, Amal Al-Enezi, Mohamed Hilmy Elnagdi

Affiliation

¹ Applied Science Department, College of Technological Studies, Public Authority for Applied Education and Training, Safat, Kuwait.

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.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Carboxylic Acids / chemical synthesis*
Carboxylic Acids / chemistry
Ethanol / chemistry
Nitriles / chemistry*
Piperidines / chemistry
Pyridazines / chemistry*

Substances

3-oxo-6-(thiophene-2-carbonyl)- 2,3-dihydropyridazine-4-carboxylic acid
6-(furan-2-carbonyl)-3-oxo-2,3-dihydropyridazine-4-carboxylic acid
6-benzoyl-3-oxo-2,3-dihydropyridazine-4-carboxylic acid
Carboxylic Acids
Nitriles
Piperidines
Pyridazines
Ethanol
piperidine
dicyanmethane