(3R,3aR,6R,6aR)-6-((5-(4-bromophenyl)-6-chloro-1-((2-(trimethylsilyl)ethoxy)methyl)-1H-imidazo[4,5-b]pyridin-2-yl)oxy)hexahydrofuro[3,2-b]furan-3-ol (intermediate 7, 527 mg, 0.904 mmol) was placed under nitrogen in formic acid (2.5 mL). A saturated aqueous solution of potassium hydrogen sulfate (0.4 mL) was added and the resulting mixture was allowed to stir at 50° C. for 9 hours. The mixture was cooled and added slowly to saturated aqueous sodium bicarbonate (200 mL). The mixture was extracted with ethyl acetate (2×150 mL) and concentrated under reduced pressure. The resulting white solid was dissolved in methanol (5 mL) and basified with 3N aqueous sodium hydroxide (2 mL). The mixture was stirred at room temperature for 10 minutes, then neutralized with 1N aqueous hydrochloric acid (6 mL). The mixture was poured into saturated aqueous sodium bicarbonate (25 mL) and extracted with ethyl acetate (2×50 mL). The combined organic layers were dried over sodium sulfate and concentrated under reduced pressure. The resulting white solid was chromatographed using a Biotage 25 g silica gel cartridge eluted with 0-5% methanol in dichloromethane over 20 minutes. The product fractions were combined, concentrated under reduced pressure, and dried under high vacuum to obtain a white solid. LC-MS: calculated for C18H15BrClN3O4 452.69 observed m/e: 454.02 (M+H)+ (Rt 1.84/4 min).
