A mixture of 1,3-dipropyl-8-(1H-pyrazol-4-yl)-7-(2-trimethylsilanyl-ethoxymethyl)-3,7-dihydro-purine-2,6-dione (0.100 g, 0.23 mmol), 1-(2-bromomethyl-cyclopropyl)-3-trifluoromethyl-benzene (0.64 g, 0.23 mmol), K2CO3 (0.063 g, 0.46 mmol) and acetone (10 ml) were heated at 50-55° C. for 16 hrs. Reaction mixture was cooled to 20-25° C. and filtered off. The filtrate was evaporated and residue was purified by column chromatography to afford 1,3-dipropyl-8-{1-[2-(3-trifluoromethyl-phenyl)-cyclopropylmethyl]-1H-pyrazol-4-yl}-7-(2-trimethylsilanyl-ethoxymethyl)-3,7-dihydro-purine-2,6-dione (0.55 g, 58%).
