1H NMR (400 MHz, CDCl3): δ 7.72 - 7.63 (m, 2H), 7.34-7.25 (m, 2H), 7.08 (dd, J = 17.2, 10.5 Hz, 1H), 6.35 (d, J = 17.1 Hz, 1H), 5.84 (d, J = 10.5 Hz, 1H), 2.34 (s, 3H). 13C NMR (100 MHz, CDCl3): δ 191.2, 138.4, 137.3, 133.8, 132.5, 130.0, 129.2, 128.4, 125.9, 21.3.