In a dried reaction flask, the crude 2-(3-chloro-4-cyanophenyl)-3-cyclopentyl-3,3a,4,5-tetrahydro-2H-pyrazolo[3,4-f]quinoline-7-carboxylic acid (Compound 1) (0.43 g, about 0.967 mmol), DIEA (0.77 mL, 4.45 mmol) and HATU (2.154 g, 5.665 mmol) were added to a mixed solvent of DMF (3.65 mL) and dichloromethane (6.8 mL) Ammonia gas was passed thereto. The mixture was stirred at room temperature for 24 hr. Water and dichloromethane were added. The mixture was extracted with dichloromethane. The combined organic phase was washed with water and saturated salt water, dried over anhydrous sodium sulfate, and concentrated at reduced pressure to produce a crude yellow solid, which was then washed with methanol and ethyl ether respectively to produce a purified product (0.18 g) in 44.3% yield.
