A Convenient and Efficient Synthesis of 2-Acetyl-5,8-Dimethoxy-1,4-Naphthoquinone

Abstract

A convenient and efficient synthesis of the important naphthazarin derivative 2-acetyl-5,8-dimethoxy-1,4-naphthoquinone is introduced in this paper. The key steps of the synthetic strategy involve the selective demethylation of 2-acetyl-1,4,5,8-tetramethoxynaphthalene with anhydrous aluminum chloride and subsequent oxidation of the demethylated product by cerium ammonium (IV) nitrate. Compared with the reported routes, the overall yield is much higher and the work-up of each step is simpler. Moreover, the reaction conditions are milder and all the reactions involved in the method are more suitable for large-scale preparations.