Potassium Hydroxide → 1-(3-Chlorophenyl)-6-(furan-2-yl)-3-methylpyrazolo[3,4-b]pyridine-4-carboxylic acid

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Reaction Steps

(see, e.g., Volochnyuk, D. M., et al., J Comb Chem 2010, 12, 510-7). A solution of ester 35 (108 mg, 0.29 mmol) and KOH (29 mg, 0.52 mmol) in iPrOH (6 mL) was refluxed for 1 h 30 min. Reaction mixture was diluted with H2O (10 mL) and washed with EtOAc (10 mL×2). Aqueous layer was acidified with 1N HCl and extracted with EtOAc (10 mL×2). Combined organic extracts were washed with brine, dried (Na2SO4), filtered, and concentrated under reduced pressure to give 1 (88 mg, 86%) as a bright yellow solid. 99% pure by HPLC. 1H NMR (400 MHz, DMSO-d6) δ 8.35 (s, 1H), 8.29 (d, J=8.5 Hz, 1H), 7.96 (s, 1H), 7.92 (s, 1H), 7.55 (t, J=8.1 Hz, 1H), 7.37-7.31 (m, 2H), 6.76-6.71 (m, 1H), 2.62 (s, 3H). 13C NMR (100 MHz, DMSO-d6) δ 166.48, 152.40, 151.70, 148.29, 146.21, 143.65, 140.42, 136.54, 133.86, 131.32, 125.57, 119.83, 118.66, 113.69, 113.32, 112.21, 112.10, 16.20. ESI MS: m/z 354.0 (M+H)+.

Provenance & Evidence