Diisopropylethylamine → 4-[4-(2-Cyano-phenoxy)-pyrazolo[3,4-d]pyrimidin-1-yl]-piperidine-1-carboxylic acid cyclopentyl ester

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Reaction Steps

Cyclopentyl chloroformate (51 mg, 0.344 mmol) was added to a mixture of 2-(1-piperidin-4-yl-1H-pyrazolo[3,4-d]pyrimidine-4-yloxy)-benzonitrile trifluoroacetate salt (which was prepared from 4-[4-(2-cyano-phenoxy)-pyrazolo[3,4-d]pyrimidin-1-yl]-piperidine-1-carboxylic acid tert-butyl ester [Example 45] following the procedure described for the preparation of Intermediate 29; 150 mg, 0.344 mmol), diisopropylethylamine (133 mg, 1.03 mmol) in dichloromethane (6 mL). The reaction was stirred at room temperature overnight. Water was added to quench the reaction and the aqueous layer was extracted three times with dichloromethane. The combined organic layers were dried (sodium sulfate), filtered, evaporated and purified by flash chromatography on silica gel, eluting with 4% methanol/dichloromethane to give 4-[4-(2-cyano-phenoxy)-pyrazolo[3,4-d]pyrimidin-1-yl]-piperidine-1-carboxylic acid cyclopentyl ester (107 mg, 72%) as a white solid. Mass spectrum MH+=433.

Provenance & Evidence