1H NMR (400 MHz, CDCl3) δ 9.21 (s, 1H), 8.95 (s, 2H), 7.41 (d, J = 10.3 Hz, 3H), 7.29 (d, J = 9.0 Hz, 2H), 2.46 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 157.36, 154.90, 139.24, 134.48, 134.22, 129.76, 129.33, 127.69, 124.10, 21.49.