1H NMR (400 MHz, CDCl3) δ 8.18 (t, J = 7.7 Hz, 2H), 7.84 (d, J = 8.1 Hz, 1H), 7.73 (t, J = 7.7 Hz, 1H), 7.57-7.50 (m, 2H), 7.36-7.31 (m, 3H), 2.41 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 160.3, 147.9, 140.7, 136.2, 136.0, 130.9, 129.7, 129.7, 129.6, 128.6, 127.5, 126.8, 126.5, 126.1, 122.4, 20.4.