4-Hydroxybenzaldehyde → 4-[6-(4-Fluorophenyl)-5-(4-pyridyl)-1H-pyrazolo[3,4-b]pyridin-4-yl]phenol

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Reaction Steps

To a solution of 1-(4-fluorophenyl)-2-(4-pyridyl)ethanone (0.30 g, 1.4 mmol, obtained in reference example 1) in 2-methoxyethanol (2 mL), 3-amino-2H-pyrazole (0.13 g, 1.5 mmol), 4-hydroxybenzaldehyde (0.17 g, 1.4 mmol), 2-methoxyethanol (2 mL) and 37% HCl (0.04 g, 0.4 mmol) were added under argon atmosphere. The mixture was heated to reflux overnight. It was allowed to cool and concentrated. The solid obtained was dissolved in CHCl3 and some drops of MeOH. Saturated NaHCO3 was added and the aqueous phase was extracted 3 times with CHCl3. The combined organic phases were dried over Na2SO4 and concentrated to dryness. The crude product was purified by chromatography on silica gel using hexane-EtOAc mixtures of increasing polarity as eluent, to afford 0.22 g of the desired compound (yield: 41%).

Provenance & Evidence