1H NMR (400 MHz, CDCl3) δ 7.32 (s, 1H), 7.23-7.14 (m, 3H), 6.35 (d, J = 14.1 Hz, 1H), 6.31-6.20 (m, 1H), 1.89 (d, J = 6.7 Hz, 3H); 13C{H} NMR (101 MHz, CDCl3) δ 139.8, 134.4, 129.8, 129.6, 127.3, 126.6, 125.8, 124.0, 18.4。