4', 8'-Diacetoxy-1, 2, 5, 6-dibenzanthraquinone (VI).-A suspension of 350 mg. of the above diacetate in 35 cc. of glacial acetic acid was refluxed for three hours with 420 mg. of anhydrous sodium dichromate and, after cooling, the orange quinone was collected and recrystallized from ethyl benzoate. It formed delicate orange needles, mp 340-345", dec.; yield 320 mg.(85%). A sample for analysis was recrystallized from ethyl benzoate and ...
