6,11-Dihydrobenzo[b]pyrrolo[4,3,2-de][1,10]phenanthroline-5,8-dione (6), which possesses a unique heterocyclic ring system similar to that in plakinidines A-D (1-4), was synthesized from 2-acetyl-3'-nitrodiphenylamine (16) in nine steps. (C) 2004 Elsevier Ltd. All rights reserved.
Weltrowski, Marek; Ledochowski, Andrzej; Sowinski, Pawel, Polish Journal of Chemistry, 1982, vol. 56, # 1, p. 77 - 82