¹H NMR (400 MHz, CDCl₃) δ 8.63 (s, 1H), 7.47 – 7.46 (m, 3H), 7.40 – 7.39 (m, 2H); ¹³C NMR (101 MHz, CDCl₃) δ 159.8 (s), 129.6 (s), 128.9 (d, J = 7.6 Hz), 124.5 (s), 116.9 (s). HRMS (EI): calculated for C₉H₆N₂O₃: 190.0378; found: 190.0377.