A mixture of (R)-7-chloro-5-cyclopentyl-4-ethyl-4,5-dihydro-[1,2,4]triazolo[4,3-f]pteridine (100 mg, 0.329 mmol), 4-amino-3-trifluoromethyl-N-methylbenzamide, palladium acetate (6 mg), cesium carbonate (214 mg, 0.658 mmol) and xanthphos (20 mg) in dioxane (4 ml) was stirred at 150° C. in a microwave for 1 hour. The mixture was diluted with ethyl acetate and washed with aqueous sodium hydrogen carbonate solution, dried over magnesium sulfate and concentrated. The residue was purified by chromatography on silica gel eluting with 0-12% methanol/ethyl acetate to give 4-((R)-5-cyclopentyl-4-ethyl-4,5-dihydro-[1,2,4]triazolo[4,3-f]pteridine-7-ylamino)-3-trifluoromethyl-N-methylbenzamide as a colourless glass (70 mg, 46%).
