反应详情

To a solution of (1,6-dihydroxy-4-methyl-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl)-acetic acid ethyl ester (3.2 mmol) in anhydrous DMF (8 mL) was added cesium carbonate (8 mmol) and 5-chloro-1,3,4-thiadiazole-2-carboxamide (3.2 mmol). The resulting mixture was stirred at room temperature overnight then quenched with crushed ice. The pH was adjusted to 2 with 6M HCl and the mixture extracted with EtOAc (2×200 mL). The organic extracts were washed with water, brine, dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified by silica gel flash column chromatography (0-75% EtOAc in hexane) to give ethyl 2-(6-(5-carbamoyl-1,3,4-thiadiazol-2-yloxy)-1-hydroxy-4-methyl-1,3-dihydrobenzo[c][1,2]oxaborol-3-yl)acetate.

1. customthen quenched with crushed ice
2. extractionthe mixture extracted with EtOAc (2×200 mL)
3. washThe organic extracts were washed with water, brine
4. dry with materialdried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customThe residue was purified by silica gel flash column chromatography (0-75% EtOAc in hexane)