1H NMR (400 MHz, CDCl3) δ 8.74 (s, 1H), 7.78 (d, J = 7.7 Hz, 2H), 7.55 (d, J = 7.6 Hz, 2H); 13C NMR (101 MHz, CDCl3) δ 160.6 (s), 132.7 (s), 129.8 (s), 129.3 (s), 117.9 (s), 113.7 (s). HRMS (EI): calculated for C10H5N3O3: 215.0331; found: 215.0337.