1H NMR (400 MHz, CDCl3) δ 7.83 (d, J = 7.7 Hz, 2H), 6.94 (d, J = 7.7 Hz, 2H), 5.82 (s, 1H), 5.60 (s, 1H), 3.87 (s, 3H), 3.54 (s, 2H), 2.13 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 195.7, 163.3, 143.9, 132.0, 130.0, 123.9, 113.6, 55.5, 35.8, 15.5. HRMS (EI): calcd for C12H14O2S: 222.0715; found: 222.0706.