Sodium hydride → tert-butyl 4-{4-amino-3-[4-(2,3-dihydrobenzo[b]furan-3-ylamino)phenyl]-1H-pyrazolo[3,4-d]pyrimidin-1-yl}-1-piperidinecarboxylate

Participants

Reaction Steps

Salicylaldehyde (0.063 g, 0.000513 mol) and tert-butyl 4-[4-amino-3-(4-aminophenyl)-1H-pyrazolo[3,4-d]pyrimidin-1-yl]-1-piperidinecarboxylate (0.200 g, 0.000489 mol) were combined in absolute ethanol (5 mL) and stirred at ambient temperature for 48 hours. The reaction mixture was concentrated under reduced pressure and the residue dried overnight to yield tert-butyl 4-[4-amino-3-(4-{[-1-(2-hydroxyphenyl)methylidene]amino}phenyl)-1H-pyrazolo[3,4-d]pyrimidin-1-yl]-1-piperidinecarboxylate which was used without further purification. Trimethylsulfoxonium iodide (0.269 g, 0.00122 mol) was dissolved in anhydrous dimethylsulfoxide (2 mL) and a 60% dispersion of sodium hydride in parafine (0.049 g, 0.00122 mol) was added at once. After 10 min., the solution of tert-butyl 4-[4-amino-3-(4-{[-1-(2-hydroxyphenyl)methylidene]amino}phenyl)-1H-pyrazolo[3,4-d]pyrimidin-1-yl]-1-piperidinecarboxylate in anhydrous dimethylsulfoxide (2 mL) was added and the resulting mixture was stirred at ambient temperature under an atmosphere of nitrogen for 2.5 hours. The solution was poured into ice-cold water (70 mL) and extracted with dichloromethane (2×50 mL). The combined organic extracts were dried with magnesium sulfate and concentrated under reduced pressure to yield crude tert-butyl 4-{4-amino-3-[4-(2,3-dihydrobenzo[b]furan-3-ylamino)phenyl]-1H-pyrazolo[3,4-d]pyrimidin-1-yl}-1-piperidinecarboxylate which was used without further purification. The crude compound was dissolved in ethyl acetate (5 mL )and treated with a 4N aqueous solution of hydrochloric acid (1.5 mL). The resulting emulsion was vigorously stirred for 1 hour; the water layer was neutralized with saturated solution of sodium bicarbonate in water and the layers were separated. The organic phase was concentrated under reduced pressure and residue was purified by preparative HPLC (Hypersil C18, 8 μm, 25 cm; 10-60% acetonitrile-0.1M ammonium acetate over 25 min, 21 mL/min) to yield 3-[4-(2,3-dihydrobenzo[b]furan-3-ylamino)phenyl]-1-(4-piperidyl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine acetate (0.038 g, 0.000078 mol) as a white solid

Provenance & Evidence