To a solution of tert-butyl (1E,4E)-4-(propylcarbamoyl)-8-(4-(pyrrolidine-1-carbonyl)phenyl)-3H-benzo[b]azepin-2-ylcarbamate (450 mg, 0.87 mmol) in CH2Cl2 (5 mL) was added 2,2,2-trifluoroacetic acid (1.36 mL, 17.4 mmol) at 0° C. The reaction mixture was warmed to room temperature and stirred for 2 h. The reaction mixture was concentrated under reduced pressure to give the crude material that was diluted with CH2Cl2 (10 mL) and sat'd aq NaHCO3 (15 mL) again. The resulting mixture was stirred for 30 min at room temperature. The aqueous layer was separated and extracted with CH2Cl2 (1×10 mL). The combined organic layers were washed with sat'd aq NaHCO3 (2×10 mL) and brine (1×10 mL), dried over MgSO4, filtered, and concentrated under reduced pressure to give the crude material again that was purified by silica gel flash column chromatography (1 to 5% MeOH in CH2Cl2, gradient) to yield 27 mg (7%) of (1E,4E)-2-amino-N-propyl-8-(4-(pyrrolidine-1-carbonyl)phenyl)-3H-benzo[b]azepine-4-carboxamide. MS APCI(+) m/z 417 (M+1) detected; 1H-NMR (400 MHz, d6-DMSO) δ 8.27 (t, 1H), 7.75 (d, 2H), 7.62 (d, 2H), 7.50 (d, 2H), 7.41 (d, 2H), 3.43-3.51 (m, 4H), 3.18 (q, 2H), 2.99 (s, 2H), 1.81-1.90 (m, 4H), 1.48-1.58 (m, 2H), 0.90 (t, 3H).
