Tetrahydrofuran → tert-butyl 4-[2-(4-oxo-2-phenyl-4,5-dihydro-2H-pyrazolo[3,4-c]quinolin-1-yl)ethyl]piperidine-1-carboxylate

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Reaction Conditions

Reaction Steps

Under a nitrogen atmosphere, a mixture of 2-phenyl-2,5-dihydro-4H-pyrazolo[3,4-c]quinoline-one (1.76 g, 6.76 mmol), N,N,N′,N′-tetramethylethylenediamine (4.5 mL), and tetrahydrofuran (75 mL) was chilled to 0° C. A solution of n-butyllithium in hexanes (8.1 mL of 2.5 M) was added dropwise. After the addition was complete the reaction mixture was stirred for 5 minutes at 0° C. and then cooled to −78° C. To the cooled solution was added tert-butyl 4-(2-iodoethyl)piperidine-1-carboxylate (3.0 g, 8.8 mmol). The reaction mixture was warmed to ambient temperature and stirred for 30 minutes before quenching with saturated aqueous ammonium chloride. The aqueous layer was extracted with chloroform. The combined organic extracts were dried over sodium sulfate, filtered, and concentrated under reduced pressure to afford a yellow oil, The yellow oil was stirred in acetonitrile and filtered to provide 1.4 g (75% pure) of tert-butyl 4-[2-(4-oxo-2-phenyl-4,5-dihydro-2H-pyrazolo[3,4-c]quinolin-1-yl)ethyl]piperidine-1-carboxylate as a tan solid.

Provenance & Evidence