Reaction Steps
A 25-mL single-neck round-bottomed flask equipped with a magnetic stirrer was charged with 238f (90 mg, 1.0 eq., 0.14 mmol), NaBH4 (23 mg, 5 eq., 0.60 mmol), and methanol (5 mL). The resulting mixture was stirred at room temperature for 20 minutes and quenched with water. It was then concentrated under reduced pressure and the residue was purified by reverse-phase prep-HPLC to afford 238 (60 mg, 66%) as a white solid. MS-ESI: [M+H]+ 637.3. 1H NMR (500 MHz, CDCl3) δ 8.69 (d, J=1.5 Hz, 1H), 8.47 (d, J=5.0 Hz, 1H), 7.99 (d, J=2.5 Hz, 1H), 7.93 (d, J=2.0 Hz, 1H), 7.86 (s, 1H), 7.36-7.31 (m, 2H), 6.83 (d, J=9.0 Hz, 1H), 6.15 (s, 1H), 5.71 (t, J=6.5 Hz, 1H), 4.96 (s, 2H), 4.72-4.63 (m, 4H), 4.52-4.51 (m, 2H), 3.97-3.95 (m, 2H), 3.75 (s, 3H), 3.55-3.53 (m, 1H), 3.48-3.46 (m, 1H), 3.10-3.08 (m, 2H), 2.91-2.89 (m, 2H), 2.58-2.56 (m, 1H), 2.49-2.48 (m, 2H), 2.23-2.19 (m, 1H), 2.08-2.02 (m, 2H), 1.93-1.89 (m, 2H), 1.00 (d, J=6.0 Hz, 3H).
