Boron tribromide → Ethyl 6-(benzenesulphonylmethyl)-3-bromo-2-hydroxybenzoate

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Reaction Steps

Boron tribromide (1M solution in DCM, 5.85 ml) was added dropwise to a stirred, cooled solution of ethyl 6-(benzenesulphonylmethyl)-3-bromo-2-methoxybenzoate (Intermediate 61, 2.3 g) in dry DCM (45 ml) at −70° C. The resultant mixture was stirred at −70° C. for 40 minutes, then allowed to warm to room temperature. It was stirred at room temperature for 2 hours then poured into sodium bicarbonate (saturated aqueous solution). The layers were separated and the aqueous layer was extracted with further DCM. The combined organic layers were washed with brine, dried (Na2SO4) and filtered. The filtrate was evaporated to dryness to give ethyl 6-(benzenesulphonylmethyl)-3-bromo-2-hydroxybenzoate (1.64 g) as a white solid.

Provenance & Evidence