1H NMR (400 MHz, CDCl3) δ 8.62 (s, 2H), 7.66 (s, 1H), 7.33 (s, 4H), 7.30 (d, J = 5.0 Hz, 4H), 2.34 (s, 6H). 13C{H} NMR (101 MHz, CDCl3) δ 148.0, 137.8, 137.1, 137.0, 135.6, 130.6, 129.9, 128.2, 126.1, 20.4。