To a solution of rac-3-iodo-1-tetrahydro-1H-3-pyrrolyl-1H-pyrazolo[3,4-d]pyrimidin-4-amine monohydrochloride (0.367 g, 1.00 mmol) in dichloromethane (10 mL) was added 2-(dimethylamino)acetic acid (0.134 g, 1.30 mmol), 1-hydroxy-7-azabenzotriazole (0.150 g, 1.10 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.249 g, 1.30 mmol), and diisopropylethyl amine (0.65 g, 0.87 mL, 5.0 mmol). The reaction mixture stirred at room temperature for 18 h and was then poured into water (10 mL). The organic phase was separated and washed with brine (10 mL), dried over anhydrous magnesium sulfate, filtered, and concentrated to afford rac-1-[3-(4-amino-3-iodo-1H-pyrazolo[3,4-d]pyrimidin-1-yl)tetrahydro-1H-1-pyrrolyl]-2-(dimethylamino)-1-ethanone as a yellow-orange solid (0.278 g, 67%) which was used in subsequent reactions without further purification. RP-HPLC Rt 4.881 min, 80% purity (5% to 85% acetonitrile/0.1M aqueous ammonium acetate, buffered to pH 4.5, over 20 min at 1 mL/min; λ=254 mn; Deltapak C18, 300 Å, 5 μm, 150×3.9 mm column); m/z 416 (MH+).
