Pyridine → tert-Butyl 5-bromo-1H-benzo[d][1,2,3]triazole-1-carboxylate

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Reaction Steps

A solution of Example 248B (770 mg; 5 mmol) in THF (5 mL) was added to a solution of 20% phosgene in toluene (10 mL) at −20° C., stirred for 1 hr. at −20° C. then 2 hrs. at r.t., evaporated and dissolved in THF (4 mL). This solution was added to a solution of tBuOH (1 mL), and pyridine (426 mg; 5.4 mmol) in THF (3 mL) at −20° C. then stirred overnight at r.t. The solids were removed by filtration and rinsed with EtOAc. The filtrate was rinsed with water and brine, dried (MgSO4), concentrated, and isolated by flash chromatography (1:1 Et2O:hexane) to provide the desired product (970 mg; 76%).

Provenance & Evidence