Boron tribromide → 4-Bromo-5-chloro-2-(2,3,4,5-tetrahydro-benzo[b]azepine-1-sulfonyl)-phenol

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Reaction Steps

To a solution of DCM (25.0 mL) containing 1-(5-bromo-4-chloro-2-methoxy-benzenesulfonyl)-2,3,4,5-tetrahydro-1H-benzo[b]azepine (2.15 g, 5 mmol) at −78° C. was added BBr3 (12.5 mL, 1M in DCM, 12.5 mmol) dropwise. The mixture was gradually warmed to rt while it was stirred for 4 hrs. The mixture was concentrated and partitioned between ethyl acetate (100 mL) and sat. NaHCO3 solution (100 mL). The organic layer was further washed with brine (2×50 mL), dried over MgSO4, and evaporated. The purification of the crude material by silica gel column chromatography eluting with hexane/ethyl acetate (6/1) yielded 4-bromo-5-chloro-2-(2,3,4,5-tetrahydro-benzo[b]azepine-1-sulfonyl)-phenol as a white solid (1.9 g). NMR (CDCl3), δ, 7.739 (1H, s), 7.186-7.259 (4H, m), 7.127 (1H, s), 3.692 (2H, m), 2.502-2.539 (2H, m), 1.802-1.868 (2H, m), 1.601-1.676 (2H, m).

Provenance & Evidence