Facile formation of hydrophilic derivatives of 5H-8,9-dimethoxy-5-[2-(N,N-dimethylamino)ethyl]-2,3-methylenedioxydibenzo[c,h] [1,6]naphthyridin-6-one (ARC-111) and its 12-aza analog via quaternary ammonium intermediates.

Several new TOP1-targeting agents were prepared using as intermediates the N,N,N-trimethyl quaternary ammonium salts of either ARC-111 or its 12-aza analog (ARC-31), 3 and 4, respectively. Direct displacement of the quaternary ammonium group with water, imidazole, alkylethylenediamines, or polyhydroxylated alkylamines provides a convenient means for furthering the structure-activity relationships associated with these non-camptothecin TOP1-targeting agents.