反应详情

To a solution [6-(5-amino-[1,3,4]thiadiazol-2-yloxy)-1-hydroxy-4-methyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl]-acetic acid ethyl ester (0.6 g, 1.72 mmol) in THF (15 mL) and methanol (2 mL) was added a solution of LiOH (0.165 g, 6.87 mmol) in water (15 mL) at 0° C. The resulting mixture was stirred at room temperature for 1.5 hours then acidified to pH=2 with dilute hydrochloric acid at 0° C. After removal of the volatile organics, the residue was neutralized to pH 7 using saturated sodium bicarbonate. The precipitated solid was filtered and stirred with ethyl acetate (20 mL) for 1 hour. The solid was filtered, washed with cold ethyl acetate and water then dried to give the product (0.412 g, 75%). 1HNMR (400 MHz, DMSO-d6) δ9.26 (br. s., 1H), 7.32 (d, J=2.05 Hz, 1H), 7.16 (d, J=1.76 Hz, 1H), 7.05 (s, 2H), 5.48 (dd, J=9.37, 2.05 Hz, 1H), 3.04 (dd, J=15.37, 2.49 Hz, 1H), 2.29 (s, 3H), 2.12 (dd, 1H). MS (ESI) m/z=322 [M+H]+.

1. customAfter removal of the volatile organics, the residue
2. filtrationThe precipitated solid was filtered
3. stirringstirred with ethyl acetate (20 mL) for 1 hour
4. filtrationThe solid was filtered
5. washwashed with cold ethyl acetate and water
6. customthen dried