Hydrochloric Acid → (1S,2S,3S,4R,5S)-2,3,4-tribenzyloxy-5-[4-chloro-3-[[4-(2,2,2-trifluoro ethoxy)phenyl]methyl]phenyl]-6,8-dioxabicyclo[3.2.1]octane-1-carboxylic acid

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Reaction Conditions

Reaction Steps

To a solution of [(1S,2S,3S,4R,5S)-2,3,4-tribenzyloxy-5-[4-chloro-3-[[4-(2,2,2-trifluoroethoxyl) phenyl]methyl]phenyl]-6,8-dioxabicyclo[3.2.1]octan-1-yl]methanol 171 (1.1 g, 1.45 mmol, obtained from the synthetic method described in step 11 of example 17) in dichloromethane (20 mL) were added sodium bicarbonate (1.58 g, 18.85 mmol), potassium bromide (172.0 mg, 1.45 mmol) and 2,2,6,6-tetramethylpiperidinooxy (22.0 mg, 0.14 mmol) in turn at 0° C., and then sodium hypochlorite (10 mL, 11.80 mmol, 3.5% available chlorine) was added dropwise. The mixture was stirred at 0° C. for 30 min and then room temperature for 1.5 hours. The reaction mixture was acidified with aqueous HCl until pH becomes 4 and partitioned. The aqueous layer was extracted with ethyl acetate (30 mL×3). The combined organic layers were washed with saturated aqueous sodium chloride (50 mL), dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated in vacuo to give the title compound 18a (0.74 g, 66.0%) as pale yellow oil. This material was not further purified.

Provenance & Evidence