¹H NMR (400 MHz, CDCl₃): δ 7.79 (d, J = 1.0 Hz, 1H), 7.69 (d, J = 4.8 Hz, 1H), 7.20-7.14(m, 1H), 7.09 (dd, J = 17.0, 10.4 Hz, 1H), 6.51 (d, J = 17.0 Hz, 1H), 5.89 (d, J = 10.4 Hz, 1H). ¹³C NMR (100 MHz, CDCl₃): δ 182.4, 144.6, 134.4, 132.5, 131.8, 129.5, 128.3.