Reaction Steps
A solution of 25% KOH in MeOH (1.21 g, 5.41 mmol) is added to a solution of 14 (1.00 g, 1.80 mmol) in 1-methylpyrrolidin-2-one (NMP, 4 mL). The resultant mixture is stirred at about 25° C. for 15 h, treated with water (15 mL), and stirred at 25° C. for 0.5 h. The resultant solids are collected via filtration, rinsed with MeOH/water (⅓, 20 mL), and dried to provide 13 as white solid. Yield: 0.68 g, 81.4%. Purity: 99.6 area % at 220 nm. 1H NMR (DMSO-d6, 500 MHz): δ 7.74 (d, J=7.1 Hz, 1H), 7.43 (d, J=7.7 Hz, 2H), 7.34 (m, 5H), 6.95 (d, J=7.7 Hz, 2H), 6.56 (s, 1H), 6.47 (d, J=6.0 Hz, 1H), 5.43 (m, 1H), 4.26 (s, 1H), 3.43 (s, 3H, 3.33 (s, 2H), 3.02 (m, 1H), 2.43 (m, 1H), 2.14 (m, 1H), 2.02 (s, 2H), 1.46 (d, J=6.8 Hz, 3H), 1.18 (s, 3H), 0.87 (s, 3H); 13C NMR (DMSO-d6, 400 MHz): δ 161.93, 152.44, 150.05, 143.37, 141.24, 139.85, 135.32, 128.33, 127.22, 127.10, 126.26, 124.90, 114.68, 103.70, 83.04, 69.30, 54.01, 52.62, 36.35, 36.22, 31.51, 30.81, 29.91, 15.46.
