An Efficient Route to Emodic Amine and Analogous <Emphasis Type="Italic">O</Emphasis>-Methyl Protected Derivatives Starting from Emodin

Summary. Emodic amine could be synthesized in a five-step approach in excellent overall yield by following a modified Curtius rearrangement strategy, starting from the naturally occurring emodin. This unique emodin derived 6-amino substituted polyhydroxylated anthraquinone may serve as a promising synthon for a new class of amino functionalized photodynamically active hypericin derivatives. In addition, the partially O-methyl protected 6-amino- and 6-carboxy-anthraquinones could be synthesized in high yields via selective O-methyl ether cleavage from the corresponding tri-O-methyl derivatives.