A suspension of 5-bromo-2-chloro-7H-pyrrolo[2,3-d]pyrimidine (100 mg, 0.43 mmol), 2-(3-bromopropyl)isoindoline-1,3-dione (173 mg, 0.65 mmol) and K2CO3 (119 mg, 0.86 mmol) in a mixture of DMSO and THF (8.0 mL, 1:3, v/v) was heated at 100° C. under microwave irradiation for 30 min. The mixture was diluted with ethyl acetate (35 mL), washed with water (3×) and concentrated to provide the crude 2-(3-(5-bromo-2-chloro-7H-pyrrolo[2,3-d]pyrimidin-7-yl)propyl)isoindoline-1,3-dione (MS m/z 420.05 [M+H]+) which was used in next step without further purification.
