1H NMR (400 MHz, CDCl3): δ 7.99-7.92 (m, 3H), 7.32 (d, J = 6.6 Hz, 3H), 7.27 (d, J = 8.0 Hz, 2H), 2.45 (s, 6H), 2.40 (s, 3H). 13C NMR (100 MHz, CDCl3): δ 181.4, 154.12, 150.2, 143.4, 139.2, 134.6, 129.5, 129.4, 129.2, 126.8, 126.5, 124.0, 117.2, 21.7, 21.5, 18.1. HRMS (EI): calcd for C20H18O2S: 322.1028; found, 322.1025.