(2-Chloro-9H-purin-6-yl)-(3,4-dimethoxy-benzyl)-amine (799 mg, 2.5 mmol) was dissolved in dry DMF (10 mL). NaH (78 mg, 3.25 mmol) was added in portions and the resulting mixture was stirred for 1 h. Cyclopentyl bromide (633 mg, 4.25 mmol) was then added and the reaction was stirred overnight at 80° C. under N2. After cooling, H2O (50 mL) was added and the mixture was extracted with CH2Cl2 (3×25 mL). The combined extracts were washed with brine (2×25 mL), dried over MgSO4, and evaporated. The residue was purified by flash chromatography (95:5 CH2Cl2/Et2O) to afford the title compound as a white powder (451 mg, 46.5%). TLC (95:5 CH2Cl2/Et2O): RF=0.27.
