1H NMR (400 MHz, CDCl3) δ 7.25 (s, 4H), 6.38-6.32 (m, 1H), 6.28-6.14 (m, 1H), 1.88 (d, J = 6.6 Hz, 3H); 13C{H} NMR (101 MHz, CDCl3) δ 136.4, 132.2, 129.9, 128.6, 127.0, 126.4, 18.4。