1H and 13C NMR characteristics of the anticancerous derivative of acridine: Ledakrin C-283 (nitracrine).

For the anticancerous derivative of acridine--Ledakrin C-283 [1-nitro-9-(3-dimethylaminopropylamino)-acridine . 2HCl-H2O] 1H and 13C NMR spectra were assigned and analysed with particular emphasis on pH effects. On pH increase in 2H2O, the deprotonation of N(10) in Ledakrin aromatic core causes a high and selective upfield shift of the resonances for aromatic protons and strong deshielding for aromatic carbons C(11)-C(14), especially those adjacent to N(10). The signals of remaining aromatic carbons are shifted upfield on increase of pH, whereas those of protons and carbons in aminoaliphatic chain at C(9) are only slightly affected by change of pH. The above NMR characteristics of Ledakrin may be useful in studies on mechanisms of its interaction with proteins and nucleic acids in aqueous solution at various pH values.