Diisopropylethylamine → (S)-tert-butyl 2-(4-chlorophenyl)-3-oxo-3-(4-(5-phenyl-1H-pyrazolo[3,4-b]pyridin-4-yl)piperazin-1-yl)propyl(isopropyl)carbamate

Participants

Reaction Steps

DIEA (0.111 mL, 0.636 mmol) was added to a solution of 5-phenyl-4-(piperazin-1-yl)-1H-pyrazolo[3,4-b]pyridine dihydrochloride (0.070 g, 0.159 mmol), (S)-3-(tert-butoxycarbonyl(isopropyl)amino)-2-(4-chlorophenyl)propanoic acid (0.0543 g, 0.159 mmol, see Example B) and O-(benzotriazol-1-yl)-N,N,N,N′-tetramethyluronium tetrafluoroborate (“TBTU”) (0.0613 g, 0.191 mmol) in DCM (1 mL) and stirred at room temperature for 1 hour. The mixture was then directly loaded onto a silica column and purified by chromatography (hexane:ethyl acetate, 1:1) to give (S)-tert-butyl 2-(4-chlorophenyl)-3-oxo-3-(4-(5-phenyl-1H-pyrazolo[3,4-b]pyridin-4-yl)piperazin-1-yl)propyl(isopropyl)carbamate as a solid. The solid was then dissolved in DCM (1 mL), and TFA (0.2 mL) was added. The mixture was stirred at room temperature for 1 hour and concentrated to dryness. The resulting residue was dissolved in DCM (0.5 mL), and HCl in ether (1 mL, 2N) was added. The resulting solid was collected by filtration to give (S)-2-(4-chlorophenyl)-3-(isopropylamino)-1-(4-(5-phenyl-1H-pyrazolo[3,4-b]pyridin-4-yl)piperazin-1-yl)propan-1-one dihydrochloride (0.044 g, 48%). MS ESI (+) m/z 503.4 detected.

Provenance & Evidence