Potassium Carbonate → (R)-5-Dipropylamino-1-methoxy-5,6-dihydro-4H-imidazo[4,5,1-ij]quinolin-2(1H)-one

Following the procedure of Example 3, a mixture of (R)-5-Propylamino-1-methoxy-5,6-dihydro-4H-imidazo[4,5,1-ij]quinolin-2(1H)-one (8b, 0.93 g, 3.56 mmol), 1-iodopropane (3.05 g, 17.9 mmol), and potassium carbonate (1.97 g, 14.3 mmol) in acetonitrile (25 ml) was heated at reflux under nitrogen for 17 hours. 1-Iodopropane (3.05 g, 17.9 mmol) was again added, and the mixture was refluxed for an additional 5 hours. The solvent was removed under vacuum, and the mixture was diluted with water and extracted twice with diethylether. The organic extract was washed with brine and dried (MgSO4). The solvent was removed under vacuum to leave an amber oil. Purification by flash chromatography (230–400 mesh silica gel; 10–25% ethyl acetate in hexane) gave the title compound (9b) as an amber oil (0.87 g, 90% yield).