Reaction Steps
The above acridine acid (0.30 g, 1.2 mmol) was reacted with CDI (0.38 g, 2.39 mmol) in dry DMF (50 mL) for 4 h at 50° C. The DMF was removed under reduced pressure, and the resulting oil was dissolved in a mixture of petroleum ether and CH2Cl2 (20 mL, 3:1). Upon cooling, the imidazolide crystallized out and this crude material was used in the following coupling reaction. The coupling was carried out by dissolving 3,3'-diamino-N-methyldipropylamine (0.09 g) in THF (50 mL), cooling to 0° C. (ice/water), and adding the crude imidazolide portionwise. The reaction mixture was allowed to stir overnight at room temperature, the THF removed, and the residue diluted with CH2Cl2 (100 mL) which was subsequently washed with 1M Na2CO3 (50 mL). The CH2Cl2 layer was dried with Na2SO4, the solvent removed under reduced pressure, and the resulting brown oil purified by chromatography on alumina (0.5% MeOH in CH2Cl2 as eluant) to give bis[(7-ethylacridine-4-carboxamido)-propyl]methylamine (22) (0.17 g, 47%) as a yellow oil. 1H NMR (CDCl3) δ 1.28 (t, J=7.5 Hz, 6 H, 2×CH3), 2.03-2.11 (m, 4 H, 2×CH2CH2CH2), 2.40 (s, 3 H, NCH3), 2.70 (q, J=7.6 Hz, 4 H, 2×CH2CH3), 2.79 (t, J=7.4 Hz, 4 H, 2×CH2NCH3), 3.74 (q, J=6.2 Hz, 4 H, 2×CH2NH), 7.46 (br s, 2 H, H-8), 7.48 (dd, J=8.9, 1.8 Hz, 2 H, H-6), 7.56 (dd, J=8.3, 7.2 Hz, 2 H, H-2), 7.89 (d, J=8.8 Hz, 2 H, H-5), 7.98 (dd, J=8.3, 1.5 Hz, 2 H, H-1), 8.51 (s, 2 H, H-9), 8.86 (dd, J=7.1, 1.5 Hz, 2 H, H-3), 11.80 (br t, J=5.0 Hz, 2 H, CONH). HRMS. (FAB+) m/z calcd for C39H42N5O2 612.3339 (MH+), found 612.3333.
