Triethylamine → 4-[4-(5-Methanesulfonyl-2,3-dihydro-indol-1-yl)pyrazolo[3,4-d]pyrimidin-1-yl]-piperidine-1-carboxylic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

5-(Methylsulfonyl)-indoline (Matrix Scientific, Columbia, S.C., USA; 30 mg, 0.15 mmol) and triethylamine (70 μL, 0.5 mmol) were added to a solution of 4-(4-chloro-pyrazolo[3,4-d]pyrimidin-1-yl)-piperidine-1-carboxylic acid tert-butyl ester (Intermediate 19; 45 mg, 0.133 mmol) in tetrahydrofuran (1 mL). The mixture was heated to reflux. No reaction had occurred after 2 h. The volatiles were evaporated. Dimethylformamide (1 mL) and cesium carbonate (250 mg, 0.77 mmol) were added. The mixture was heated at 70° C. overnight, then poured into saturated aqueous sodium bicarbonate, and extracted three times with ethyl acetate. The combined organic extracts were washed twice with water and once with brine, dried (magnesium sulfate), filtered, evaporated, and purified by column chromatography eluting with ethyl acetate to give 4-[4-(5-methanesulfonyl-2,3-dihydro-indol-1-yl)pyrazolo[3,4-d]pyrimidin-1-yl]-piperidine-1-carboxylic acid tert-butyl ester (14 mg, 21%) as an off-white solid.

Provenance & Evidence