Synthesis of novel pyrano fused quinolones, coumarins, and pyridones

Article abstract of DOI:10.1002/jhet.5570360222

A novel efficient synthesis of pyrano fused heterocycles namely, pyrano[3,2-c]quinoline-2,5(6H)-diones 3a-e, 7b-d, pyrano[3,2-c]benzopyran- 2,5(6H)-dione (7f), and pyrano[3,2-c]pyridine-2,5(6H)-diones 10, 11 was achieved by the condensation of 4-hydroxy-2-(1H)-quinolones 1a-e, 4- hydroxycoumarin (1f), or 4-hydroxy-2(1H)-pyridone (9) with α-acetyl-γ- butyrolactone (2) or the sodium salt of α-formyl-γ-butyrolactone (6), respectively, in the presence of ammonium acetate.