Reaction Steps
To a solution of 171a (90 mg, 0.136 mmol) in methanol (10 mL) was added NaBH4 (26 mg, 0.7 mmol) at room temperature. After the reaction was stirred for 1 h, LCMS indicated the reaction was complete. It was quenched with water (30 mL) and concentrated under reduced pressure. The residue was extracted with dichloromethane (3×30 mL). The combined organic layer was washed with brine (30 mL), dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue solid was purified by reverse-phase prep-HPLC to afford 171 (35 mg, 31.5%) as light yellow solid. MS-ESI: [M+H]+ 663.3. 1H NMR (500 MHz, DMSO-d6) δ 8.62 (s, 1H), 8.48 (d, J=5.0 Hz, 1H), 8.44 (s, 1H), 7.83 (d, J=2.5 Hz, 1H), 7.47 (s, 1H), 7.38 (dd, J=2.5, 9.0 Hz 1H), 7.34 (d, J=5.0 Hz, 1H), 7.24 (d, J=9.5 Hz, 1H), 6.51 (s, 1H), 4.97 (t, J=4.5 Hz, 1H), 4.58-4.54 (m, 2H), 4.50-4.37 (m, 4H), 4.30-4.24 (m, 2H), 3.86-3.84 (m, 1H), 3.69-3.67 (m, 1H), 3.60 (s, 3H), 3.47 (s, 1H), 3.42-3.37 (m, 1H), 3.30 (s, 2H), 3.10-3.07 (m, 1H), 2.95-2.92 (m, 1H), 2.36-2.29 (m, 3H), 2.21-2.16 (m, 1H), 1.88-1.754 (m, 3H), 1.60-1.58 (m, 1H), 1.08-1.05 (m, 1H), 0.98-0.96 (m, 1H), 0.93 (d, J=6.0 Hz, 3H).
