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 [Me12TPPFe(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)-beta-octahaloporphyrinatoiron(III) chlorides [Cl8betaX8TPPFe(III)Cl] (X=Cl, Br) (1c, 1d) gives specifically 5,8-dioxopsoralen (4) in moderate yields.
Chauhan
S M
SM
Department of Chemistry, University of Delhi, India.
Sahoo
B
B
Mohapatra
P P
PP
Kalra
B
B
Gulati
A
A
D002384:Catalysis; D003374:Coumarins / Q000138:chemical synthesis*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008730:Methoxsalen / Q000138:chemical synthesis*; D010084:Oxidation-Reduction; D021241:Spectrometry, Mass, Electrospray Ionization; D013481:Superoxides / Q000737:chemistry*
C447040:6-formyl-7-hydroxy-8-methoxycoumarin; D003374:Coumarins; D013481:Superoxides; D006861:Hydrogen Peroxide; D008730:Methoxsalen