Synthesis of a 6H-Pyrazolo[4,5,1-de]acridin-6-one Derivative: A Useful Intermediate of Antitumour Agents - Sugaya, Toru; Mimura, Yukiteru; Kato, Nobuyuki; Ikuta, Masanori; Mimura, Takashi; Kasai, Masaji; Tomioka, Shinji (Synthesis, 1994)