1H NMR (400 MHz, CDCl3) δ 7.28 (dd, J = 8.7, 5.7 Hz, 2H), 6.97 (t, J = 8.6 Hz, 2H), 6.36 (d, J = 14.5 Hz, 1H), 6.19-6.10 (m, 1H), 1.87 (d, J = 6.6 Hz, 3H); 13C{H} NMR (101 MHz, CDCl3) δ 161.8 (d, J = 245.3 Hz), 134.1 (d, J = 3.2 Hz), 129.8, 127.2 (d, J = 7.9 Hz), 125.4 (d, J = 2.3 Hz), 115.3 (d, J = 21.4 Hz), 18.4。