1,4-Diamino-2,3-ditbromoanthracene-9,10-dione or 1,4-Diamino-2,3-dichloroanthracene-9,10-dione in copper catalyst and tie acid agent under the existence of condensation.
3,3'-Dichloro-4,4'-diaminoindanthrone, Indanthren Green BB, is prepared from 1,4-diamino-2,3-
dichloroanthraquinone in naphthalene in the
presence of copper powder .
