Sodium borohydride (0.031 g) was added to a solution of methyl 6-(benzenesulfonylmethyl)-3-(2-formylfuran-3-yl)-2-hydroxybenzoate (Intermediate 28, 0.67 g) in methanol (6 mL) and THF (12 mL) at 0° C. and the resultant mixture was stirred at 0° C. for 10 minutes. Saturated aqueous ammonium chloride, ethyl acetate and water were added and the organic layer was separated, washed with brine, dried (Na2SO4) and filtered. The filtrate was evaporated to dryness and the residue was purified by chromatography on silica, eluting with a mixture of ethyl acetate and cyclohexane with a gradient of 30-80% to give methyl 6-(benzenesulfonylmethyl)-2-hydroxy-3-(2-hydroxymethylfuran-3-yl)-benzoate (0.65 g) as a white solid.
