To a solution of cis-4-amino-2-methyl-2,3,4,6,7,8-hexahydro-cyclopenta[g]quinoline-1-carboxylic acid ethyl ester (Example 3) (0.35 g, 1.28 mmol) in anhydrous 1,2-dichloroethane (50 mL) was added acetic acid (0.73 mL, 1.28 mmol), followed by 3,5-bis(trifluoromethyl)benzaldehyde (0.21 mL, 1.28 mmol) and sodium triacetoxyborohydride (0.406 g, 1.92 mmol). The reaction was stirred at room temperature for 18 h. The reaction mixture was then diluted with chloroform and washed with 1 N NaOH. The organic layer was separated, dried over magnesium sulfate, filtered and concentrated in vacuo. Purification by silica gel chromatography using 10% ethyl acetate/hexanes as eluent afforded the title compound (approximately 300 mg). 1H NMR (CDCl3) δ1.1 (d, 3H), 1.3 (t, 3H), 2.6 (m, 1H), 3.6 (dd, 1H), 4.5 (m, 1H), 7.30 (s, 1H), 7.35 (s, 1H), 7.8 (s, 1H), 8.0 (s, 2H).
