Substituted Quinolinones. Part 19. New and Unexpected Results from Oxidation of 3-Acetyl-1-Alkyl- 4-Hydroxyquinolin-2(1H)-Ones Using Selenium Dioxide

Synthesis of New Quinolinones from 3-Nitropyranoquinolinones

Alkaline hydrolysis of 3-nitropyranoquinolinones (6-alkyl-4-hydroxy-3-nitro-2 H-pyrano[3,2- c]quinoline-2,5(6 H)-diones) for different reaction times gave five products which were formed by the progressive degradation of the nitropyrano ring. Varying amounts of 3-nitroacetylquinolinones, quinolinones with side-chains of β- and α-ketoacids, quinolinone-3-carboxylic acids and 4-hydroxyquinolinones were isolated. With the aim of preparing new biologically active quinolone derivatives, the products of reaction of the 3-nitropyranoquinolinones with side-chains of β- and α-ketoacids with some nitrogen and carbon nucleophiles were also studied, some giving rise to annulated products.