tert-Butanol (1 mL) and N,N′-dicyclohexylcarbodiimide (0.4 g) were added to a solution of 6-(benzenesulfonylmethyl)-3-bromo-2-hydroxybenzoic acid (Intermediate 39, 0.48 g) and DMAP (0.016 g) in THF (10 mL) and the mixture was stirred for 18 hours. It was evaporated to dryness and the residue was suspended in DCM and the insoluble material was removed by filtration. The filtrate was evaporated to dryness and the residue was purified by chromatography on silica, eluting with DCM to give tert-butyl 6-(benzenesulfonylmethyl)-3-bromo-2-hydroxybenzoate (0.34 g).
