Cesium carbonate → 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

Participants

Reaction Steps

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.

Provenance & Evidence