Diisopropylethylamine → 5-Benzyloxy-2-(4,4-difluoro-piperidine-1-carbonyl)-pyrrolo[2,3-b]pyridine-1-carboxylic Acid tert-butyl Ester

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Reaction Steps

To the solution of 2.3 g (6.2 mmol) 5-benzyloxy-pyrrolo[2,3-b]pyridine-1,2-dicarboxylic acid 1-tert-butyl ester (intermediate G), 2.5 g (7.8 mmol) O-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate and 1.2 g (7.8 mmol) 4,4-difluoropiperidine hydrochloride in 30 ml DMF, 6.4 ml (4.8 g, 37.4 mmol) N,N-diisopropylethylamine were added. After 40 min. stirring at room temperature the clear solution was poured on saturated aqueous sodium bicarbonate solution and was extracted three times with ethyl acetate. The combined organic layers were washed three times with water and with brine, dried over magnesium sulfate, filtered and evaporated. The residue was re-crystallized from dichloromethane and n-heptane to give 2.8 g (95%) of the desired compound as a colorless solid.

Provenance & Evidence