Lithium hydroxide, monohydrate → 1-(5-(2-Fluorophenyl)pyrimidin-2-yl)-3-(methylsulfinyl)-1H-indole-6-carboxylic acid

Lithium hydroxide monohydrate (0.34 g, 8.05 mmol) in water (2 mL) was added to an ice-cooled suspension of methyl ester 51d) (2.2 g, 5.37 mmol) in THF/water (1:1; 40 mL) and the resulting mixture was stirred at room temperature for 16 h. The solvent was removed under vacuum and the remnant was dissolved in water (20 mL) and washed with ethyl acetate (2×20 mL). The aqueous phase was acidified with sodium hydrogen sulfate and extracted with dichloromethane (2×50 mL). The organic layers were dried over sodium sulfate and evaporated. White solid. Yield: 1.8 g (85% of theory). HPLC-MS (method 5): Rt=2.6 min; m/z [M+H]+=396