Reaction Steps
(2S)-2-(1,1-Dioxidoisothiazolidin-2-yl)-4-methyl-N-[(3aS,4R,6aR)-octahydrocyclopenta[c]pyrrol-4-yl]pentanamide (204 mg, 0.594 mmol) and 3-(trifluoromethyl)benzaldehyde (0.158 mL, 1.188 mmol) were dissolved in dichloromethane (3 mL). Acetic acid (1 mL) was added. The reaction was stirred at ambient temperature for 20 min, then PS-cyanoborohydride (487 mg, 1.188 mmol) was added. The reaction was stirred at room temperature overnight, then filtered, and the solvent was removed in vacuo. The crude material was purified by silica gel chromatography using 1-10% methanol (2 N ammonia)/dichloromethane to the title compound: 1H NMR (500 MHz, pyridine-d5) δ ppm 8.79 (d, J=7.0, 1H), 7.75 (d, J=10.3, 1H), 7.61-7.54 (m, 2H), 7.44 (t, J=7.7, 1H), 4.52 (dd, J=6.6, 8.9, 1H), 4.38 (dq, J=6.4, 12.6, 1H), 3.94 (dd, J=7.3, 16.2, 1H), 3.57 (dd, J=9.1, 13.5, 1H), 3.50-3.37 (m, 2H), 3.31-3.19 (m, 2H), 2.79 (ddd, J=3.0, 9.1, 19.0, 1H), 2.62-2.54 (m, 1H), 2.54-2.45 (m, 1H), 2.43-2.36 (m, 1H), 2.31-2.16 (m, 4H), 2.13-2.03 (m, 1H), 1.94-1.78 (m, 3H), 1.77-1.59 (m, 2H), 1.39 (dt, J=6.5, 19.8, 1H), 0.88 (d, J=6.6, 3H), 0.82 (dd, J=2.3, 6.5, 3H); MS (ESI+) m/z 502 (M+H)+.
