1H NMR (400 MHz, CDCl3) δ 7.83 (d, J = 8.0 Hz, 2H), 7.77 (d, J = 8.0 Hz, 2H), 6.01 (s, 1H), 5.67 (s, 1H), 3.53 (s, 2H), 2.13 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 195.3, 143.5, 141.1, 132.2, 129.7, 127.3, 117.9, 115.7, 34.9, 15.6. HRMS (EI): calcd for C12H11NOS: 217.0561; found: 217.0554.