25. Oxidation of Heterocyclic β-Dicarbonyl Compounds
Stadlbauer W., Kappe Th.
Heterocycles 21 (1984) 653
Abstract: Oxidation of 4-hydroxy-2-quinolones (1)
leads to 3-hydroxy-3-substituted quinoline-2,4-diones (2).
Extension of this reaction to barbituric acids 4 gives
5-hydroxybarbituric acids 5.