A solution of 3-(2-chloroethyl)-8-mesityl-2,6-dimethylimidazo[1,5-a]pyrimidin-4-ol (200 mg, 0.58 mmol) and N,N-dimethylaniline (0.3 mL) in phosphorus oxychloride (3 mL) was heated under reflux for six hours. After overnight, 3-aminopentane (2 mL) was added to a solution of the residue in acetonitrile (5 mL), followed by stirring at 80° C. for three hours. Water was added, and the mixture was extracted with ethyl acetate, washed with brine, dried over anhydrous magnesium sulfate and evaporated. The residue was purified by silica gel column chromatogrpahy (10-20% ethyl acetate/hexane), to give the title compound (139 mg) as pale yellow crystals.
