4664-01-1

40107-95-7

General procedure: 3,4-pyridinedicarboximide (0.40 g, 2.7 mmol, 1.0 eq.) was dissolved in acetic acid (12 mL) and zinc powder (0.78 g, 11.9 mmol, 4.4 eq.) was added. The suspension was heated to reflux for 24 hours. After completion of the reaction, it was cooled to room temperature and the mixture was filtered through a diatomaceous earth pad. The filtrate was concentrated under reduced pressure and the residue was dissolved in dichloromethane (CH2Cl2). Anhydrous calcium chloride (CaCl2) was added to this solution and the insoluble material was removed by filtration. The filtrate was concentrated again under reduced pressure and the resulting crude product was purified by column chromatography using ethyl acetate/methanol (95:5, v/v) as eluent. The target fraction was collected, concentrated and crystallized from ethanol to give 1H-pyrrolo[3,4-c]pyridin-3(2H)-one (0.061 g, 17% yield) as a yellow solid. Product characterization: melting point 190-193 °C (decomposition); 1H NMR (300 MHz, DMSO-d6) δ 8.84 (s, 1H), 8.70 (br d, 2H), 7.62 (d, J = 5.5 Hz, 1H), 4.42 (s, 2H); 13C NMR (75 MHz, DMSO-d6) δ 169.1, 153.3 , 151.6, 145.3, 129.0, 119.9, 45.2; GC-MS m/z 134 (M+); IR (KBr) 2856, 1728, 1692, 1455, 1206, 1026 cm-1. Calculated elemental values (C7H6N2O): C, 62.68; H, 4.51; N, 20.88. measured values Calculated values for elemental analysis (C7H6N2O): C, 62.68; H, 4.51; N, 20.88.