Thermal-Induced Dimerization Cyclization of Ethyl N-(Styrylcarbamoyl)acetates: Formation of 4-Hydroxy-2(1H)-pyridone-3- carboxamide Derivatives

Abstract

Thermal-induced dimerization cyclization of ethyl N-(styrylcarbamoyl)acetate derivatives has been investigated, leading to 4-hydroxy-2(1H)-pyridone-3-carboxamide derivatives with good yields in diphenyl ether on 200–210 °C. Ethyl N-(styrylcarbamoyl)acetate derivatives readily provided the intermolecular cyclization products 4-hydroxy-2(1H)-pyridone-3-carboxylates on reflux in xylene. In addition, several related 3-acetyl-4-hydroxy-5-phenylpyridin-2(1H)-ones have been prepared. It provided an efficient preparation of 4-hydroxy-2(1H)-pyridone-3-carboxamide derivatives.

GRAPHICAL ABSTRACT

Keywords:

• Ethyl N-(styrylcarbamoyl)acetate
• 4-hydroxy-2(1H)-pyridone-3-carboxamide
• intramolecular thermal cyclization

Notes

^a Reaction conditions: compounds 5a (2.0 mmol) was stirred in solvent for the time indicated in Table 1.

^b Isolated yield with column chromatography.

^a Reaction conditions: compounds 5 (2.0 mmol) was stirred in diphenyl ether at 200–210 °C for the time indicated in Table 2.

^b Isolated yield with column chromatography.

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