反应详情

To a solution of (1,6-dihydroxy-4-methoxymethyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl)-acetic acid ethyl ester (0.20 g, 0.67 mmol) in THF (6 mL) and H2O (2 mL) was added LiOH (0.130 g) at 0° C. The resulting mixture was stirred at room temperature for 2 hours then cooled to 0° C. and acidified to pH 3 with 6N HCl. The mixture was concentrated in vacuo and the residue was purified by preparative HPLC to give (1,6-dihydroxy-4-methoxymethyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl)-acetic acid (0.120 g, 71%). 1H NMR (400 MHz, DMSO-d6) δ 12.24 (s, 1H), 9.42 (s, 1H), 9.10 (s, 1H), 6.99 (s, 1H), 6.82 (s, 1H), 5.46 (m, 1H), 3.28 (s, 3H), 3.03 (m, 1H), 2.02 (m, 1H). MS (ESI) m/z: 251 [M−1]−. HPLC purity: 97.87% (220 nm), 98.47% (Maxplot).

1. temperaturethen cooled to 0° C.
2. concentrationThe mixture was concentrated in vacuo
3. customthe residue was purified by preparative HPLC