A mixture of 2-butoxy-8-methoxy-9H-purin-6-amine trifluoroacetate salt (200 mg) and potassium carbonate (236 mg) in dry DMF (2 mL) were heated at 60° C. with stirring for 1 h. 2-(Tetrahydro-2H-pyran-2-yl)ethyl methanesulfonate (142 mg) was added and the reaction was continued for 16 h at 60° C. The mixture was quenched with water and extracted with EtOAc (×3). The combined organics were washed with water and brine, dried using a hydrophobic frit and evaporated to give crude material (540 mg). The material was purified by normal phase chromatography (ISCO) using 0-20% methanol/EtOAc as eluent to give the title compound as a white solid (88 mg).
