Ether synthesis (via hydroxyl):
Dimethylaminoethanol (25 ml, 248 mmol) was slowly added to the suspension of sodium hydride (55% dispersion in mineral oil, 3.14 g, 71.9 mmol) in dioxane (25 mL) at 4°C, and then stirred for 30 min at room temperature. 2-Butylamino-9-(6-chloropyridin-3- yl)methyl-8-oxoadenine (5.0 g, 14.4 mmol) was added to the mixture then stirred for 4 hours under reflux. The reaction was quenched with water (100 ml) and cone. HCl aq. (20 ml) at 0°C then extracted with CHCl3/EtOH=3/1 three times. The combined organic layers were washed with brine, dried over MgSO4 and concentrated in vacuo. The residue was purified by silica gel column chromatography to afford titled compound as white solid. 4.90 g, 12.2 mmol, 85% yield.
Patent reference: WO2010033074 (Astrazeneca)