6-Bromo-4-chloro-7H-pyrrolo[2,3-d]pyrimidine

784150-40-9

784150-41-0

Synthesis of compound 20.2. Potassium tert-butanolate (1.2 g, 10 mmol) was added to a solution of tetrahydrofuran (THF, 24 mL) of compound 20.1 (6-bromo-4-chloro-7-(phenylsulfonyl)-7H-pyrrolo[2,3-D]pyrimidine, 800 mg, 2.2 mmol). The reaction mixture was stirred at room temperature for 16 hours. Upon completion of the reaction, the reaction was quenched by the addition of saturated sodium bicarbonate (NaHCO3) solution. The reaction mixture was extracted with ethyl acetate (EtOAc, 3 × 100 mL). The organic layers were combined, washed sequentially with water and brine, and then dried over anhydrous sodium sulfate (Na2SO4). The solvent was evaporated under reduced pressure to give the crude product. The crude product was purified by fast column chromatography using silica gel (SiO2) as stationary phase and hexane/ethyl acetate (100/0 to 0/100) as eluent to afford compound 20.2 (6-bromo-4-chloro-7H-pyrrolo[2,3-d]pyrimidine, 400 mg, 80% yield). The product was characterized by 1H-NMR (200 MHz, DMSO-d6) and mass spectrometry (MS): 1H-NMR δ 13.41 (broad single peak, 1H), 8.57 (single peak, 1H), 6.79 (single peak, 1H); MS m/z 232 [M + 1]+.