1H NMR (400 MHz, CDCl3) δ 8.71 (s, 1H), 7.11 (d, J = 3.6 Hz, 1H), 7.09 (d, J = 3.7 Hz, 1H); 13C NMR (101 MHz, CDCl3) δ 160.0 (s), 130.7 (s), 129.9 (s), 125.3 (s), 115.3 (s), 110.4 (s). HRMS (EI): calculated for C7H3N2O3SBr: 273.9048; found: 273.9044.