Ethyl 8-iodo-1-methyl-4,5-dihydro-1H-pyrazolo[4,3-h]quinazoline-3-carboxylate (4.0 g, 10.4 mmol) prepared as described in WO2004/104007 was dissolved in anhydrous ethanol (150 mL) and treated with potassium hydroxide (5.83 g, 104 mmol.) at RT for 24 hour. The white precipitate formed during the reaction was collected by filtration. The solid was then suspended in anhydrous dimethylformamide (5.0 mL) and treated with N-ethyl-N,N-diisopropylamine (10 ml) and O-(Benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate (TBTU) (4.5 g, 14.1 mmol). The mixture was then treated with 2,6-diethylaniline (2.3 ml, 14.1 mmol) and stirred at room temperature overnight. The solvent was removed under reduced pressure and the crude was purified by column chromatography to afford the title compound.
