Water → 3-chloro-2-hydroxy-5-[3-(2-methoxy-phenyl)-1H-pyrazolo[3,4-b]pyridin-5-yl]-benzoic acid

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Reaction Steps

240 mg (0.46 mmol) of 3-chloro-2-hydroxy-5-[3-(2-methoxy-phenyl)-1-(2-trimethylsilanyl-ethoxymethyl)-1H-pyrazolo[3,4-b]pyridin-5-yl]-benzoic acid was dissolved in 5 mL of glacial acetic acid. 500 μL of 70% perchloric acid was added and the mixture stirred at ambient temperature for 24 h. 50 mL of water was added and the resulting precipitate filtered off and dried by suction to afford 117 mg (0.29 mmol, 64%) of 3-chloro-2-hydroxy-5-[3-(2-methoxy-phenyl)-1H-pyrazolo[3,4-b]pyridin-5-yl]-benzoic acid as a yellow solid. 1H NMR (500 MHz, DMSO-d6) δ 8.83 (d, 1H), 8.34 (d, 1H), 8.14 (d, 1H), 8.07 (d, 1H), 7.66 (dd, 1H), 7.47 (ddd, 1H), 7.22 (d(d), 1H), 7.10 (ddd, 1H), 3.84 (s, 3H), MS: m/z 394.0 (M−H+).

Provenance & Evidence