Sodium Hydroxide → Methyl 5-{[6-chloro-5-(1-methyl-1H-indol-5-yl)-1H-benzimidazol-2-yl]oxy}-2-methylbenzoate

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To a solution of methyl 5-[(6-chloro-5-(1-methyl-1H-indol-5-yl)-1-{[2-(trimethylsilyl)ethoxy]methyl}-1H-benzimidazol-2-yl)oxy]-2-methylbenzoate (335 g, 5.81 mmol) in THF (60 mL) was added TBAF (1.0 M in THF) (26 mL, 26.1 mmol) dropwise via syringe. The reaction was heated at 80° C. for 45 min. TBAF (3 mL) was added and heating continued for 4 h. The reaction was cooled and diluted with EtOAc (200 mL) and saturated aqueous KHSO4 (˜pH 3). The aqueous phase was extracted with EtOAc (100 mL). The combined organic layers were washed with H2O and brine, dried (Na2SO4), filtered, and concentrated. The residue was dissolved in MeOH (100 mL) and treated with 2.5 N aqueous NaOH (46 mL, 115 mmol). The reaction was heated at 45° C. for 1 h. Volatiles were removed and the residue was dissolved in H2O (150 mL). The aqueous phase was washed with EtOAc (2×100 mL), acidified to pH ˜1 with 2 N aqueous HCl and extracted with EtOAc (2×100 mL). The combined organics were washed with H2O and brine, dried (Na2SO4), filtered, and concentrated. Trituration of the solid residue with Et2O and filtration afforded the title compound as an off-white solid. LC-MS: m/e 432.6 (M+H)+ (2.0 min). 1H NMR (500 MHz, CD3OD): δ 7.85 (d, 1H), 7.54 (d, 1H), 7.47 (s, 1H), 7.44-7.37 (m, 3H), 7.35 (s, 1 H), 7.22 (dd, 1H), 7.18 (d, 1H), 6.45 (d, 1H), 3.83 (s, 3H), 2.61 (s, 3H).

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