Formation of 6-Formyl-7-hydroxy-8-methoxycoumarin and 5, 8-Dioxopsoralen by Reaction of 8-Methoxypsoralen with H2O2 and Potassium Superoxide (KO2) Catalyzed by Halogenated or Perhalogenated 5, 10, 15, 20-Tetraarylporphyrinatoiron(III) Chlorides

The oxidation of 8-methoxypsoralen (2) with hydrogen peroxide and potassium superoxide catalyzed by 5, 10, 15, 20-(2, 4, 6-trimethylphenyl)porphyrinatoiron(III) chlorides [Me12-TPPFe(III)Cl] (1a) and 5, 10, 15, 20-(2, 6-dichlorophenyl)porphyrinatoiron(III) chlorides [Cl8TPPFe(III)Cl] (1b) in dichloromethane gives 6-formyl-7-hydroxy-8-methoxycoumarin (3) in moderate yields, whereas the oxidation of (2) with H2O2 catalyzed by 5, 10, 15, 20-(2, 6-dichlorophenyl)-β-octahaloporphyrinatoiron(III) chlorides [Cl8βX8TPPFe(III)Cl] (X=Cl, Br) (1c, 1d) gives specifically 5, 8-dioxopsoralen (4) in moderate yields.