3-Nitro-6-azaindole

271-29-4

67058-77-9

General procedure for the synthesis of 3-nitro-1H-pyrrolo[2,3-c]pyridine from 6-azaindole: 69% nitric acid (533 mg, 8.47 mmol) was slowly added to a solution of 1H-pyrrolo[2,3-c]pyridine (1 g, 8.47 mmol) in concentrated sulfuric acid (5 mL) at 0 °C. The reaction mixture was stirred at 0 °C for 2 h before gradually warming to room temperature and continuing to stir overnight. Upon completion of the reaction, the mixture was carefully poured into water (100 mL) and the pH was adjusted with sodium hydroxide powder to >7. Subsequently, the mixture was extracted with ethyl acetate (100 mL x 3), the organic phases were combined and dried over anhydrous sodium sulfate. The organic phase was concentrated under reduced pressure to afford 3-nitro-1H-pyrrolo[2,3-c]pyridine (690 mg, 50% yield) as a yellow solid. The product was confirmed by NMR hydrogen spectroscopy (400 MHz, DMSO-d6): δ=8.94 (s, 1H), 8.85 (s, 1H), 8.44 (d, J=5.2 Hz, 1H), 8.02 (dd, J=5.6,1.2 Hz, 1H). Mass spectral analysis showed m/z of 164.0 (M+H).