1,4-NAPHTHOQUINONES .26. PHENYL-1,4-NAPHT HOQUINONE DERIVATIVES WITH THE HYDROXYLATION PATTERNS OF BIOFLAVONOIDS

Flavonoids with special hydroxylation patterns are inhibitors of cyloo xygenase and lipoxygenases of the arachidonic acid cascade. To get met abolically more stable compounds with higher lipophilicity and with a similar molecular topography 2-phenyl-1,4-naphthoquinones with analogo us hydroxylation patterns of bioflavonoids are snythesized on two diff erent ways: 1. Meerwein arylation of 1,4-naphthoquinone (1a-e) with me thoxybenzendiazonium tetrafluoroborates (2a-b) and 2. regiospecific re spectively regioselective arylation of 2-halogen- and 2,3-dihalogen-1, 4-naphthoquinone derivatives (9a-d) with 2,6-di-tert-butylphenol follo wed by partial or complete debutylation. In the case of preparing il-h ydroxyphenyl derivatives, the second way is the more effective method because the synthesis by Meerwein arylation needs two additional prote cting groups. The final deprotection results in rather low yields. Wit h the second method without additional protecting procedures it was po ssible to get 12c and 13c in quite a short time. These two compounds p osses the essential hydroxyl functions for the inhibition of cyclo- an d 5-lipoxygenase as the natural flavonoids apigenin and kaempferol do.