Efficient synthesis of 1,4-dihydroxy-9 (10H) - anthracenone

An efficient synthesis of the 1,4- dihydroxy-9(10H)- anthra-cenone (2) is described. Bromination of phthalide, treated with 1,4-di-methoxybenzene, oxidation with ceric ammonium nitrate(CAN) in aqueousacetonitrile, reduction with zinc dust in glacial acetic acid affordedhydroquinone 14 in good yield. Further reduction with zinc dust inaqueous sodium hydroxide, and cyclization with trifluoroacetic acid andtrifluoroacetic anhydride produced the title compound in high yield.