2, 4, 6-Trihydroxy-5-keto-5, 12-dihydronaphthacene(ⅩⅡ) is choosen as a model for the synthesis of desdimethylaminoterrarubein(Ⅰ), an important degradation product of the antibiotic terramycin.The synthesis of(ⅩⅡ) is approached by two different routes.One is the Friedel-Crafts acylation of(Ⅴ) with(Ⅵ) and the other is the boric acid condensation of(Ⅱ) and(Ⅲ).