The role of retro-Michael reaction in the synthesis of 5-carbamoyl-2-pyridones by reaction of dialkyl ethoxymethylidenemalonates with acetoacetamides

摘要

The reaction of dialkyl ethoxymethylidenemalonates with arylamides of acetoacetic acid was studied for the purpose of creating a new method for the synthesis of substituted 2-pyridones containing a carbamoyl group. This reaction was shown to occur in the presence of triethylamine in ethanol solution at room temperature, forming mainly retro-Michael products, N, 1-diaryl-5-acetyl-2-methyl-6-oxo-1,6-dihydropyridine-3-carboxamides. Simultaneously, depending on the molar ratio of reagents, triethylammonium 5-acetyl-3-alkoxycarbonyl-1-aryl-6-oxo-1,6-dihydropyridin-2-olates were also formed at the same time. The results of this reaction can be explained by the different acidity of the acidic hydrogen atoms in Michael adduct.