Potassium acetate (0.41 g, 4.16 mmol) and potassium iodide (0.28 g, 1.66 mmol) were added to a stirring solution of 2-(chloromethyl)-1-(tetrahydro-2H-pyran-4-ylmethyl)-1H-imidazo[4,5-c]quinolin-4-amine (0.55 g, 1.66 mmol) and the resulting suspension was heated to 50° C. After 17 hours, the suspension was cooled to ambient temperature and concentrated under reduced pressure. The residue was suspended in methanol (10 mL) and water (5 mL) and lithium hydroxide monohydrate (0.35 g, 8.31 mmol) was added in one portion. The resulting solution was stirred at ambient temperature 18 hours and concentrated under reduced pressure. The residue was diluted with water (20 mL) and neutralized with hydrochloric acid (6 N in water). The aqueous layer was extracted with dichloromethane (2×50 mL) and ethyl acetate (50 mL). The combined organic fractions were concentrated to a yellow solid which was crystallized from acetonitrile. The crystals were isolated by filtration and dried in a vacuum oven at 65° C. to provide 0.20 g of [4-amino-1-(tetrahydro-2H-pyran-4-ylmethyl)-1H-imidazo[4,5-c]quinolin-2-yl]methanol as an off-white solid, mp 239-241° C.
