Abstract 4-Substituted 3-hydroxy-2 (1 H)-pyridinones 2 were prepared by Mannich reaction of 3-hydroxy-2 (1 H)-pyridinones with secondary amines and formaldehyde. The isolated products were then reacted with aromatic amines in the presence of NaIO 3 as oxidant via oxidation–Michael addition to yield 4, 5, 6-trisubstituted-2, 3-pyridinediones 3 in good yields (80.2–88.9%). The structures of the products were characterized by 1 H NMR, ESI-MS, ...
