1H NMR (400 MHz, CDCl3) δ 8.62 (s, 1H), 7.37 (t, J = 7.8, J = 7.7 Hz, 1H), 7.05 – 6.88 (m, 3H), 3.83 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 159.8 (s), 130.1 (s), 125.6 (s), 121.1 (s), 116.7 (s), 115.0 (s), 114.7 (s), 55.4 (s). HRMS (EI): calculated for C10H8N2O4: 220.0484; found: 220.0482.