¹H NMR (400 MHz, CDCl₃) δ 7.45-7.33 (m, 4H), 6.74 (dd, J = 17.6, 10.9 Hz, 1H), 5.79 (d, J = 17.5 Hz, 1H), 5.30 (d, J = 10.9 Hz, 1H), 4.60 (s, 2H). ¹³C{H} NMR (101 MHz, CDCl₃) δ 137.7, 136.9, 136.1, 128.8, 126.5, 114.5, 46.0。