Hydrochloric Acid → 1-(1-hydroxy-2-piperidin-4-ylethyl)-2-phenyl-2,5-dihydro-4H-pyrazolo[3,4-c]quinolin-4-one

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Reaction Steps

Tert-butyl 4-[2-hydroxy-2-(4-oxo-2-phenyl-4,5-dihydro-2H-pyrazolo[3,4-c]quinolin-1-yl)ethyl]piperidine-1-carboxylate (100 mg, 0.2 mmol) was combined with concentrated hydrochloric acid (1 mL) and stirred at ambient temperature for 30 min. The reaction was poured over ice and the pH of the ice slurry was brought to 12 with 50% aqueous sodium hydroxide. The aqueous layer was extracted with dichloromethane. The combined organic extracts were dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting material was purified by automated flash chromatography (AnaLogix, eluted with a gradient of 0-60% CMA in chloroform) to provide an oily solid. The oily solid was stirred in acetonitrile. A solid was isolated by filtration to provide 40 mg of 1-(1-hydroxy-2-piperidin-4-ylethyl)-2-phenyl-2,5-dihydro-4H-pyrazolo[3,4-c]quinolin-4-one as a tan powder, mp 258-261° C. MS (APCI) m/z 389 (M+H)+; Anal. calcd for C23H24N4O2.0.6H2O: C, 69.19; H, 6.36; N, 14.03. Found: C, 69.02; H, 6.23; N, 14.11.

Provenance & Evidence