The dechlorinated rebeccamycin anhydride (II) was prepared from rebeccamycin (I) by hydrogenolysis using Raney Nickel in aqueous sodium hydroxide. Further bromination of (II) with N-bromosuccinimide afforded dibromo derivative (III). Imide (IV) was then prepared by treatment of anhydride (III) with ammonium acetate at 180 C.