A mixture of 6-fluoro-1-(phenylsulfonyl)-3-(1H-pyrazol-4-yl)-1H-indole (Intermediate 5; 443 mg; 1.30 mmol), 2-(2-oxopyrrolidin-1-yl)ethyl methanesulfonate (Intermediate 43; 400 mg; 1.93 mmol), Cs2CO3 (1.30 g; 3.99 mmol) in DMF (10 mL) was stirred at 90° C. overnight. The reaction mixture was diluted with water (40 mL) and extracted with EtOAc (40 mL×3). The combined organic layers were washed with brine (30 mL), dried over anhydrous Na2SO4, filtered, and concentrated to afford 285 mg (48%) of the title compound as a brown solid, which was used directly used without further purification.
