Hydrochloric Acid → 1-(4-aminobutyl)-2-phenyl-1H-imidazo[4,5-c]quinolin-4-amine

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Reaction Steps

The tert-butyl N-[4-(4-amino-2-phenyl-1H-imidazo[4,5-c]quinolin-1-yl)butyl]carbamate (4.3 g, 10.0 mmol) was dissolved in methanol (15 mL) and 1 N hydrochloric acid (100 mL) and then heated at reflux for 2 hours. The reaction mixture was concentrated under vacuum to a volume of about 50 mL. Addition of concentrated ammonium hydroxide to pH 12 did not produce a precipitate. The pH was adjusted to 7 with 1 N hydrochloric acid. The mixture was extracted with dichloromethane and then with ethyl acetate. The aqueous layer was concentrated to dryness. The residue was dissolved in water (50 mL) and then extracted continuously with refluxing chloroform for 36 hours. The chloroform extract was concentrated under vacuum to provide a light tan solid. This material was recrystallized from acetonitrile to provide 2.5 g of 1-(4-aminobutyl)-2-phenyl-1H-imidazo[4,5-c]quinolin-4-amine as an off white solid, m.p. 175–177° C. Analysis: Calculated for C20H21N5: % C, 72.48; % H, 6.39; % N, 21.13; Found: % C, 72.72; % H, 6.32; % N, 20.71.

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