Regioselective Synthesis of O-Methyl Derivatives of the Trihydroxy Anthraquinones Morindone and Nataloe-Emodin

Abstract

Cycloaddition chemistry of dichloronaphthoquinones has led to regioselective syntheses of all regioisomeric α-O- methyl derivatives of morindone (2) and nataloe-emodin (4), including the natural anthraquinone ethers (1) and (3).