The preparation of gram quantities of 1,4,5,8-tetramethoxyanthracene
from commercially available and inexpensive 1,8-dihydroxyanthraquinone
is described. The key steps in the synthesis involve bromination
of 1,8-dimethoxyanthracene to form 1,8-dibromo-4,5-dimethoxyanthracene
followed by Cu(I) catalyzed replacement of bromo substituents with
methoxy groups. The contrasting reports concerning the preparation
of 1,8-dimethoxyanthracene from 1,8-dimethoxyanthraquinone
using zinc dust in refluxing acetic acid are also discussed.
anthraquinones - polycyclic aromatic hydrocarbons - copper(I) bromide - bromination
- zinc