Reaction Steps
To a solution of 165a (100 mg, 0.15 mmol) in methanol (10 mL) was added NaBH4 (34 mg, 0.90 mmol) at room temperature. After the reaction was stirred for 1 h, LCMS indicated the reaction was complete. Then the mixture was quenched with water (8 mL) and concentrated under reduced pressure. The residue was extracted with dichloromethane (3×10 mL). The combined organic layer was washed with brine (30 mL), dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified by reverse-phase prep-HPLC to afford 165 (35 mg, 35%) as light yellow solid. MS-ESI: [M+H]+ 663. 1H NMR (500 MHz, DMSO-d6) δ 8.64 (s, 1H), 8.57 (d, J=5.0 Hz, 1H), 8.44 (s, 1H), 7.82 (d, J=2.0 Hz, 1H), 7.51-7.48 (m, 2H), 7.35 (dd, J=2.0 Hz, 9.0 Hz, 1H), 7.27-7.23 (m, 2H), 6.83-6.81 (m, 2H), 4.97 (bs, 1H), 4.59-4.55 (m, 2H), 4.49-4.32 (m, 4H), 3.61 (s, 3H), 3.51-3.47 (m, 1H), 3.42-3.37 (m, 1H), 3.17-3.16 (m, 1H), 3.01-2.98 (m, 1H), 2.76-2.74 (m, 2H), 2.63-2.61 (m, 3H), 2.55-2.54 (m, 1H), 2.19-2.16 (m, 1H), 2.12-2.07 (m, 1H), 1.90-1.85 (m, 2H), 1.77-1.66 (m, 3H), 1.27-1.25 (m, 1H), 0.79 (t, J=7.0 Hz, 3H).
