348640-02-8

271-63-6

98-59-9

348640-02-8

1. To a stirred solution of 7-azaindole (6.0 g, 50.0 mmol, 1.0 eq.) in THF (20 mL) at 0 °C was slowly added NaH (60% dispersion, 2.2 g, 66.0 mmol, 1.3 eq.). 2. The reaction mixture was gradually warmed to room temperature and stirred continuously for 30 minutes. 3. After the reaction mixture was cooled to 0 °C again, p-toluenesulfonyl chloride (TsCl, 11.6 g, 60.0 mmol, 1.2 eq.) was added. 4. The reaction mixture was stirred at room temperature overnight. 5. Upon completion of the reaction, the reaction was quenched with water and extracted with ethyl acetate (EtOAc). 6. The organic layers were combined, washed with saturated brine, dried over anhydrous sodium sulfate (Na2SO4) and concentrated under reduced pressure to remove the solvent. 7. Purification of the crude product by column chromatography (eluent: hexane/ethyl acetate gradient) afforded 1-(4-methylbenzenesulfonyl)-1H-pyrrolo[2,3-b]pyridine (Intermediate 1a) as a white solid (12.8 g, 93% yield, 100% UPLC purity).