To a 3-L, three-neck flask equipped with a temperature probe, nitrogen line and overhead stirrer was charged with free base of 277 (crude from previous reaction, 0.328 mol) and ethanol (500 mL). The mixture was heated to 50° C. until a clear solution was obtained. The solution was cooled to room temperature and added to a solution of 2 M HCl in ether (200 mL) slowly. After 5 min, precipitation of HCl salt was observed. The slurry was stirred for 1 h at room temperature and filtered. The cake was washed with a mixture of MTBE/EtOH (2:1, 200 mL) and dried over night under high vacuum to yield 277 hydrochloride [80.8 g, 70%, 98.0% (AUC) by HPLC]. 1H NMR (D2O, 300 MHz): δ 7.65 (d, 1H), 7.55 (d, 1H), 7.5 (dd, 1H), 3.5 (s, 2H), 2.5 (s, 6H), 2.15 (dd, 2H), 1.85 (dt, 2H), 1.5 (dd, 2H), 1.3 (dt, 2H), 0.05 (s, 3H).
