Many oxidation systems using iron or manganese prphyrins as catalysts and various oxygen atom donors have been reported to mimic cytochrome P-450-dependent monoo~ygenases'-~). Such systems are very efficient for epoxidation of al kenes and reasonably for alkane hydroxylation. Few authors also reported about the activity to hydroxylate aromatic rings. In these cases low yields were found for hydroxylation of anisole, benzene, naphthalene, and toluene&'). Biomimetic systems based on metalloporphyrin catalystscan be used for preparative oxidation of some substrates and appear particularly useful for the preparation of oxidized metabolites of drugs or other xenobi-
OtiCS.The aim of our investigations is the development of a model which is able to afford potential metabolites and possibly predicts the metabolism of drugs with diphenylmethane structure. Various substituted porphyrins were compared as catalysts for the oxygenation of 4-methoxybenzophenone (1) by H 2 0 2 , iodosobenzene (PhIO), pentafluoroiodosobenzene (PhF510)8). or NaOC1. Two reactions were expected to take place: 0-demethylation and aromatic hydroxylation. Further we investigated the influence of different N-bases on the qualitative and quantitative results of aromatic hydroxylation.
Results and DiscussionThe reaction of 4-methoxybenzophenone (1) shown in Scheme 1 affords 4-hydroxybenzophenone (2) and 3-hydroxy-4-methoxybenzophenone (3).We used meso-tetraphenylporphyrins (TPP) bearing no halogen substituent, chlorine substituents at the ortlw-positions of the phenyl rings (TDCPP) and additional bromine substituents on all pyrrole rings (TDCBrgP), fluorine substituents at all positions of the phenyl rings (TPFPP), 4-methoxy-(MOPP), 3,5-di-(trifluoromethyl)-@TFMPP), or 2-trifluoromethyl-meso-tetraphenylporphyrin (TFMPP)9). The "Presented in part as a poster contribution on the pdEurapean Congress of pharmaceutical Sciences from
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