To a solution of 8-bromo-7-(4-chlorobenzyl)-3-methyl-1H-purine-2,6(3H,7H)-dione (150 mg, 0.405 mmol, intermediate 8) in DMF (5 mL) was added 1-(2-bromoethyl)cyclopropanol (94 mg, 0.568 mmol) followed by potassium carbonate (84 mg, 0.609 mmol) and TBAI (catalytic amount). The resulting mixture was stirred at 50° C. overnight. The reaction was diluted with ethyl acetated and washed with brine. The organic phase was dried and concentrated to give crude product which was purified via silica gel chromatography eluting with petroleum ether/ethyl acetate (5:1 to 2:1) to give 8-bromo-7-(4-chlorobenzyl)-1-(2-(1-hydroxycyclopropyl)ethyl)-3-methyl-1H-purine-2,6(3H,7H)-dione (150 mg, 81.6% yield) as light yellow solid. LCMS retention time 1.523 min; LCMS MH+ 455.
