1H NMR (400 MHz, CDCl3): δ 7.53 (d, J = 7.5 Hz, 2H), 7.40 (t, J = 7.4 Hz, 1H), 7.37-7.28 (m, 5H), 7.15 (s, 1H), 2.43 (s, 3H), 2.40 (s, 3H), 2.32 (s, 3H). 13C NMR (100 MHz, CDCl3): δ 184.5, 156.8, 151.4, 137.8, 137.3, 137.2, 131.2, 130.9, 130.7, 130.2, 129.8, 128.4, 128.3, 125.5, 125.1, 123.7, 119.1, 20.7, 19.8, 18.1. HRMS (EI): calcd for C20H18O2S: 322.1028; found, 322.1023.