Reaction Steps
To a solution of 7a (70 mg, 0.10 mmol) in MeOH (2 mL) was added 6 N HCl (4 mL) at room temperature. The mixture was stirred for 12 h and then concentrated. The crude product was purified by recrystallization (EtOH/H2O) to give inhibitor 3a (38 mg, 97%): 1H NMR (500 MHz, D2O) δ 2.18 (s, 3H), 2.68-2.73 (m, 1H), 2.76-2.82 (dd, J=7.0, 15.5 Hz, 1H), 2.85-2.90 (dd, J=8.0, 15.0 Hz, 1H), 3.04-3.09 (t, J=11.5 Hz, 1H), 3.15-3.25 (m, 2H), 3.39-3.43 (dd, J=8.5, 11.5 Hz, 1H), 3.50-3.53 (d, J=13.5 Hz, 1H), 3.53-3.60 (m, 1H), 3.73-3.80 (m, 1H), 4.05-4.10 (m, 1H), 4.22 (s, 2H), 6.47 (s, 1H), 6.53 (s, 1H), 7.12-7.14 (dd, J=1.0, 8.5 Hz, 1H), 7.16-7.18 (dd, J=1.0, 8.0 Hz, 1H), 7.35-7.40 (m, 1H); 13C NMR (125 MHz, D2O) δ 21.0, 28.8, 41.3, 44.67, 44.70, 46.4, 47.1, 49.3, 63.9, 78.0, 110.3, 114.0, 115.8, 115.9, 117.4, 117.5, 125.0, 125.1, 132.1, 132.2, 132.3, 132.4, 145.7, 153.8, 158.1, 160.1, 162.0; LC-TOF (M+H) calcd for C20H28FN4O 359.2247. found 359.2253.
