Hydrochloric Acid → HCID 58292817, compound

Participants

Reaction Steps

To a solution of (3R)-(1,6-dihydroxy-4-methyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl)-acetic acid ethyl ester (2.0 g, 7.9 mmol) in anhydrous DMF (20 mL) were added Cs2CO3 (15.4 g, 47.4 mmol) and methyl iodide (1.43 g, 9.6 mmol) at 0° C. After stirring at room temperature for 4 hours the reaction mixture was cooled to 0° C. and acidified to pH 2 with concentrated HCl. The mixture was extracted with ethyl acetate and the organic extracts were washed with water, brine, dried over sodium sulfate and concentrated in vacuo. The residue was purified by silica gel flash column chromatography (30-100% EtOAc in hexane) to give (3R)-(1-hydroxy-6-methoxy-4-methyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl)-acetic acid ethyl ester as a yellow foam (0.7 g, 35%). 1H NMR 400 MHz (DMSO-d6) δ9.12 (s, 1H), 7.07 (d, J=2.0 Hz, 1H), 6.85 (d, J=2.0 Hz, 1H), 5.46 (dd, J=9.2, 2.4 Hz, 1H), 4.09-4.03 (m, 2H), 3.74 (s, 3H), 3.17-3.07 (m, 1H), 2.26 (s, 3H), 2.23-2.17 (m, 1H), 1.16-1.12 (m, 3H).

Provenance & Evidence