¹H NMR (400 MHz, CDCl₃) δ 7.33 (d, J = 8.4 Hz, 2H), 7.15 (d, J = 7.7 Hz, 2H), 6.71 (dd, J = 17.6, 10.7 Hz, 1H), 5.72 (d, J = 17.5 Hz, 1H), 5.20 (d, J = 11.0 Hz, 1H), 2.36 (s, 3H). ¹³C{H} NMR (101 MHz, CDCl₃) δ 137.6, 136.7, 134.8, 129.2, 126.1, 112.7, 21.2。