1H NMR (400 MHz, CDCl3): δ 7.88 (d, J = 8.9 Hz, 2H), 7.82 (s, 2H), 7.43 (s, 2H), 7.36 (t, J = 7.7 Hz, 1H), 7.32 (s, 1H), 7.21 (d, J = 7.1 Hz, 1H), 2.46 (s, 6H), 2.43 (s, 3H). 13C NMR (100 MHz, CDCl3): δ 182.0, 154.0, 150.1, 138.4, 138.4, 137.3, 133.4, 129.9, 129.8, 129.4, 128.6, 128.3, 127.1, 126.5, 124.1, 123.8, 117.8, 21.5, 21.4, 18.1. HRMS (EI): calcd for C20H18O2S: 322.1028; found, 322.1030.