SYNTHESIS OF NAPHTHOQUINONE DERIVATIVES .13. A NOVEL SYNTHESIS OF NAPHTHAZARIN AND JUGLONE DERIVATIVES BY REACTION OF NAPHTHAZARIN AND JUGLONE WITH CYCLIC ENOL ETHERS

The reaction of naphthazarin with cyclic enol ethers in acetic acid in the presence of BF3.OEt2 gave naphthazarin derivatives such as cyclos hikonin, having a cyclic ether substituent, in one step. Cyclic enol e thers did not attack the quinone ring of naphthazarin but the benzene ring, and the corresponding naphthazarin derivatives were produced aft er tautomerization. This reaction was applicable to juglone to give ju glone derivatives bearing a cyclic ether substituent.