A solution of 6-amino-1-(2-(dimethylamino)ethyl)-3,4-dihydroquinolin-2(1H)-one (0.045 g, 0.182 mmol) in dry ethanol (5 mL) was treated with methyl thiophene-2-carbimidothioate hydroiodide (0.103 g, 0.361 mmol) at room temperature and the resulting mixture was stirred over night (18 h). The reaction was diluted with ether (45 mL) and the precipitate collected by vacuum filtration. The precipitate was washed from the filter with methanol and the solvent was evaporated. The residue was diluted with 1N sodium hydroxide solution (5 mL) and product was extracted into ethyl acetate (3×10 mL). The combined ethyl acetate layer was washed with brine and dried (Na2SO4). The solvent was evaporated and crude was purified by column chromatography (2M ammonia in methanol:dichloromethane, 1:19). Product was dried under high vacuum. Yield: 40 mg of yellow oil 4 (58%) 1H NMR (CDCl3) δ 7.44 (dd, J=1, 5.4 Hz, 1H), 7.41 (d, J=3.3 Hz, 1H), 7.09 (t, J=4.2 Hz, 1H), 7.03 (d, J=8.4 Hz, 1H), 6.88 (dd, J=2.1, 8.4 Hz, 1H), 6.83 (d, J=2.1 Hz, 1H), 4.87 (br s, 2H), 3.98 (t, J=7.2 Hz, 2H), 2.87 (t, J=7.2 Hz, 2H), 2.63 (t, J=7.2 Hz, 2H), 2.37 (t, J=7.2 Hz, 2H), 2.25 (s, 6H), 1.89-1.79 (m, 2H). MS (ESI): 357.2 (M+1). ESI-HRMS calculated for C19H25N4SO (MH+): 357.1743, Observed: 357.1752.
