¹H NMR (400 MHz, CDCl₃): δ 7.95 (d, J = 7.7 Hz, 2H), 7.58 (t, J = 7.3 Hz, 1H), 7.48 (t, J = 7.5 Hz, 2H), 7.16 (dd, J = 17.1, 10.6 Hz, 1H), 6.44 (d, J = 17.1 Hz, 1H), 5.94 (d, J = 10.6 Hz, 1H). ¹³C NMR (100 MHz, CDCl₃): δ 191.1, 137.2, 133.0, 132.4, 130.2, 128.7, 128.6.