Synthesis of 2(1H)-quinolinonequinones and 2-alkoxy-quinolinequinones using oxidative demethylation with cerium (IV) ammonium nitrate

2,5,8(1H)-Quinolinetriones (12), 2,5,6(1H)-quinolinetriones (13), 2-alkoxy-5,8-quinolinediones (14), 2,8-dimethoxy-5,6-quinolinedione (15), and 2,6-dimethoxy-7,8-quinolinediones (16) were synthesized by oxidative demethylation of the corresponding 2(1H-quinolinones (7) and 2-alkoxyquinolines (11) with cerium (IV) ammonium nitrate