Reaction Steps
A solution of Compound 13 (30.0 g, 0.68 mmol,) in 1:1 (v/v) MeOH/H2O (900 mL) was filtered through a glass-sintered funnel. The filtrate was then stirred at room temperature as a saturated solution of aqueous NaHCO3 (45 mL) was slowly added over 30 minutes, causing the solution to turn cloudy. Previously prepared seed crystals (0.10 g,) were then added to the batch in one portion. Additional saturated aqueous NaHCO3 (555 mL) was added to the reaction mixture over 1.5 h. The slurry was filtered to afford a wet cake. The wet filter cake was then suspended in 8:2 (v/v) H2O/MeOH (250 mL) and the resulting slurry was stirred for 3 hours and then filtered. The filter cake was washed with 8:2 (v/v) H2O/MeOH (100 mL) and the obtained white solid was dried in vacuo at 50° C. for 30 h to give Compound 2 (23.2 g, 93% yield): 1H NMR (d6-DMSO, 300 MHz) δ 7.80-7.90 (m, 3H), 7.74-7.78 (m, 3H), 7.65 (dd, J=8.6; 2.1 Hz, 1H), 7.43-7.53 (m, 2H), 7.38 (dd, J=8.6; 2.1 Hz, 1H), 6.90 (d, J=8.0 Hz, 1H), 6.83 (d, J=9.1 Hz, 1H), 6.45 (s, 2H), 4.43 (t, J=5.9 Hz, 1H), 3.73 (s, 2H), 3.00 (dd, J=10.7, 5.4 Hz, 1H), 2.70 (dd, J=11.3; 7.5 Hz, 1H), 2.37 (s, 3H); 13C NMR (75 MHz, DMSO) ppm 159.69, 149.65, 142.55, 136.95, 135.62, 134.79, 132.93, 131.83, 129.47, 127.67, 127.46, 127.40, 127.28, 127.16, 125.98, 125.47, 125.15, 123.32, 123.06, 114.12, 60.63, 57.82, 45.55, 44.69, 40.34.
