2, 3, 6, 7-Tetrabromonaphthazarin (11).-Five g.(1 mole) of pure sublimed naphthazarin was dissolved in 139 cc. of glacial acetic acid and treated with 15.9 g. of bromine (a little less than four moles). The mixture was boiled under a reflux for eight hours. The product separated on cooling the solution. It was recrystallized from glacial acetic acid, using 35-45 cc. of acid for each gram of product. The crystals are slender, flat, bronze-colored needles, ...
