1,3-Dihydro-2H-pyrrolo[3,2-b]pyridin-2-one

295327-27-4

32501-05-6

General procedure for the synthesis of 4-azaindol-2-one from 2-(3-aminopyridin-2-yl)ethyl acetate: 2-(3-aminopyridin-2-yl)ethyl acetate (6.94 g, 0.038 mol) was dissolved in ether (100 mL) at room temperature. A 2 M hydrochloric acid solution (35 mL) was added slowly and the reaction mixture was stirred for 30 minutes. Subsequently, the volatile solvent was removed by rotary evaporation to give a brown solid product. This crude product was purified by recrystallization from a solvent mixture of ethanol and ether to give white crystals of 4-azaindol-2-one (4.0 g, 62% yield). The structure of the product was confirmed by 1H NMR (400 MHz, DMSO-d6): δ 12.35 (s, 1H), 8.12 (m, 1H), 7.90 (m, 1H), 7.14 (m, 1H), 5.75 (s, 2H). Electrospray mass spectrometry (ESI-MS) showed the molecular ion peak m/z 135 ([M+H]+).