To a solution of 3,3-dibromo-4-chloro-1H-pyrrolo[2,3-b]pyridin-2(3H)-one (350 mg, 1.072 mmol) in methanol (5 mL) was added acetic acid (5 mL), followed by addition of zinc powder (351 mg, 5.36 mmol) in batches. The reaction mixture was stirred at room temperature for 1 hour. After completion of the reaction, the mixture was diluted with ethyl acetate (50 mL) and filtered through diatomaceous earth. The filtrate was neutralized with 10% aqueous sodium bicarbonate. The organic layer was separated, dried over anhydrous sodium sulfate, filtered and concentrated to give a brown solid. The solid was washed with hexane (2 x 20 mL) to afford 4-chloro-1H-pyrrolo[2,3-b]pyridin-2(3H)-one (164 mg, 0.973 mmol, 91% yield) as an off-white solid. lcms (ESI) m/z 168.9 [M+H]+ (calculated value C7H6ClN2O, 169.01); lc/ms retention time (Method B): tR = 0.58 min.
![3,3-DibroMo-4-chloro-1H-pyrrolo[2,3-b]pyridin-2(3H)-one](/CAS/20150408/GIF/346600-25-7.gif)
![4-chloro-1H-pyrrolo[2,3-b]pyridin-2(3H)-one](/CAS/GIF/346599-62-0.gif)