Reaction Steps
To a solution of II (0.9 g, 3.2 mmol) in 10 mL of methanol was added potassium hydrogen fluoride (0.25 g, 3.2 mmol). A solution of 30% hydrogen peroxide in water (0.88 mL, 7.7 mmol) was slowly added, and the reaction mixture was stirred and heated at 55° C. for 8 h. To the crude mixture was added K2CO3 until the pH of the solution became slightly basic (pH 8–9). After filtration of the solid and evaporation of the solvent, the crude product was purified by radial PLC (EtOAc) to yield 82% of III as a white solid. IR (neat) 2598, 23448, 1643 cm−1; 1H NMR (300 MHz, CDCl3) δ 8.68 (s, 1H), 8.58–8.56 (m, 1H), 8.12 (dd, 1H, J=1.5 and 8 Hz), 7.47 (dd, 1H, J=5.1 ans 8 Hz), 4.61 (dd, 1H, J=7.2 and 12 Hz), 3.79–3.59 (m, 2H), 2.94 (s, 3H), 2.72–2.1 (m, 4H); 13C NMR (75 MHz, CD3OD) δ 170.5, 152.8, 151.4, 141.3, 124.9, 78.3, 71.4, 54.1, 29.5, 21.1. HRMS Calcd for C10H14N2O: 179.1184. Found: 179.1190 [M+H]+. [α]D25: +23.8 (c=0.8, MeOH). IR (neat) 2598, 23448, 1643 cm−1, 1H NMR (300 MHz,) δ 8.68 (s, 1H), 8.58–8.56 (m, 1H), 8.12 (dd, 1H, J=1.5 and 8 Hz), 7.47 (dd, 1H, J=5.1 ans 8 Hz), 4.61 (dd, 1H, J=7.2 and 12 Hz), 3.79–3.59 (m, 2H), 2.94 (s, 3H), 2.72–2.1 (m, 4H); 13C NMR (75 MHz, CD3OD) δ 170.5, 152.8, 151.4, 141.3, 124.9, 78.3, 71.4, 54.1, 29.5, 21.1. HRMS Calcd for C10H14N2O: 179.1184. Found: 179.1190 [M+H]+. [α]D25+23.8 (c 8, MeOH).
