1H NMR (400 MHz, CDCl3) δ 9.62 (s, 1H), 7.57 (d, J = 7.6 Hz, 2H), 7.52-7.42 (m, 3H), 7.30 (s, 1H), 2.11 (s, 3H); 13C{H} NMR (101 MHz, CDCl3) δ 195.5, 149.8, 138.3, 135.1, 130.0, 129.5, 128.7, 10.9。