1H NMR (400 MHz, CDCl3) δ 7.51 (d, J = 7.6 Hz, 2H), 7.41 (d, J = 7.6 Hz, 2H), 7.34 (dd, J = 12.5, 7.0 Hz, 4H), 7.28 (d, J = 7.0 Hz, 1H), 6.21 (s, 1H), 4.64 (t, J = 6.7 Hz, 1H), 4.59 - 4.44 (m, 2H), 2.66 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 141.5, 139.9, 134.2, 131.6, 128.5, 127.7, 127.5, 124.8, 122.2, 121.4, 75.3, 66.8, 34.9.