Sodium hydride → tert-butyl 4-(5-bromo-1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridin-4-yl)piperazine-1-carboxylate

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Reaction Conditions

Reaction Steps

NaH (0.144 g, 3.59 mmol) in DMF (5 mL) was added dropwise to a solution of 5-bromo-1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridin-4-ol (1.00 g, 2.99 mmol) in dimethylformamide (“DMF”) (10 mL). The reaction mixture was warmed to 40° C. and stirred for 30 minutes. After cooling to room temperature, 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (1.28 g, 3.59 mmol) was added and stirred at room temperature for 1 hour. tert-Butyl piperazine-1-carboxylate (1.23 g, 6.58 mmol) was then added. The mixture was warmed to 80° C. and stirred for 1 hour. The reaction was then cooled to room temperature, and a saturated ammonium chloride solution (30 mL) was added. The reaction mixture was extracted with ethyl acetate (2×20 mL) and dried over sodium sulfate, filtered and concentrated. The resulting residue was purified by column chromatography (hexane:ethyl acetate, 5:1) to give tert-butyl 4-(5-bromo-1-(4-methoxybenzyl)-1H-pyrazolo[3,4-b]pyridin-4-yl)piperazine-1-carboxylate (1.23 g, 82%) as a solid. MS ESI (+) m/z 504.3 detected. 1H NMR (400 Hz, DMSO-d6) δ 8.42 (s, 1H), 8.28 (s, 1H), 7.17 (d, J=8.8 Hz, 2H), 6.82 (d, J=8.8 Hz, 2H), 5.48 (s, 2H), 3.66 (s, 3H), 3.49 (m, 8H), 1.40 (s, 9H).

Provenance & Evidence