A Facile Synthesis of 4-Alkyl-2-Quinolones

The derivatives of 4-alkyl-2-quinolones possess a variety of biological activities. The general synthetic method of 4-alkyl-2-quinolones is the reaction of aryl amines with β-ketoesters to form β-ketoamides, which are then heated in concentrated sulfuric acid to complete the ring closure. Although a number of its 4-methyl and aryl derivatives have been obtained, other 4-alkyl-2-quinolones are rarely mentioned for lack of a convenient method to prepare the appropriate β-ketoesters used in condensation.