合成路线1

Friedel Crafts condensation of p-dimethoxybenzene (I) with dichloromaleic anhydride (II) in a molten mixture of AlCl3 and NaCl yielded dichloronaphthazarin (III). Subsequent methylation of (III) with CH3I in the presence of Ag2O in CHCl3 gave a mixture of dimethoxy naphthoquinones (IV) and (V), from which the desired isomer (IV) was isolated by recrystallization from CHCl3-CCl4. Finally, treatment of (IV) with 3-methoxyphenol (VI) and Na2CO3 in DMSO at room temperature furnished the target compound.