Reaction Steps
A suspension of isoquinoline-5-sulfonyl chloride hydrochloride (0.83 g in 50 ml of pyridine, 3.1 mmol) was added dropwise to a stirring solution of 1-(4-aminobutyl)-2-butyl-1H-imidazo[4,5-c]quinoline-4-amine (1.0 g, 3.2 mmol) and dichloromethane (175 ml). The solution turned a bright yellow color and was maintained at room temperature for 4 hours. An additional 0.18 g of isoquinoline-5-sulfonyl chloride hydrochloride was added and the reaction was maintained an additional 60 hours. The yellow solution was concentrated in vacuo, dissolved in dichloromethane, and washed sequentially with saturated aqueous sodium bicarbonate and water. The organic fraction was dried (MgSO4), filtered, and concentrated in vacuo. The residue was purified by flash column chromatography (silica gel, 9:1 dichloromethanemethanol) to provide 0.7 g of N5-[4-(4-amino-2-butyl-1H-imidazo[4,5-c]quinolin-1-yl)butyl]-5-isoquinolinesulfonamide as a white crystalline solid, m.p. 96.0° C. (decomposition). 1H NMR (300 MHz, DMSO-d6) δ 9.44 (d, J=0.7 Hz, 1H), 8.64 (d, J=6.1 Hz, 1H), 8.41-8.35 (m, 2H), 8.30 (dd, J=7.4, 1.2 Hz, 1H), 8.11 (t, J=5.6 Hz, 1H), 7.92 (d, J=7.6 Hz, 1H), 7.75 (t, J=7.7 Hz, 1H), 7.61 (dd, J=8.3, 1.2 Hz, 1H), 7.41 (dt, J=7.7, 1.2 Hz, 1H), 7.22 (dt, J=7.6, 1.2 Hz, 1H), 6.47 (broad s, 2H), 4.38 (t, J=7.5 Hz, 2H), 2.86-2.74 (m, 4H), 1.78-1.63 (m, 4H), 1.50-1.34 (m, 4H), 0.94 (t, J=7.4 Hz, 3H); MS (EI) m/e 502.2151 (502.2151 calcd for C27H30N6O2S). Anal calcd for C27H30N6O2S: C, 64.52; H, 6.02; N, 16.72. Found: C, 64.03; H, 6.03; N, 16.55.
