1H NMR (400 MHz, CDCl3): δ 8.45 (s, 1H), 8.03 (d, J = 8.6 Hz, 1H), 7.96 (d, J = 8.0 Hz, 1H), 7.91 (d, J = 8.6 Hz, 1H), 7.88 (d, J = 8.1 Hz, 1H), 7.60 (t, J = 7.4 Hz, 1H), 7.55 (t, J = 7.4 Hz, 1H), 7.32 (dd, J = 17.1, 10.6 Hz, 1H), 6.50 (d, J = 17.1 Hz, 1H), 5.97 (d, J = 10.5 Hz, 1H). 13C NMR (100 MHz, CDCl3): δ 190.8, 135.5, 134.6, 132.5, 132.4, 130.4, 130.1, 129.5, 128.6, 128.5, 127.8, 126.8, 124.4.