1H NMR (400 MHz, CDCl3) δ 7.46 (d, J = 7.3 Hz, 2H), 7.40 (d, J = 7.3 Hz, 2H), 7.33 (d, J = 7.5 Hz, 3H), 7.17 (d, J = 7.6 Hz, 2H), 6.19 (s, 1H), 4.73 - 4.65 (m, 1H), 4.62 - 4.49 (m, 2H), 2.76 - 2.63 (m, 2H), 2.36 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 142.5, 137.2, 137.2, 134.2, 129.2, 128.5, 127.7, 126.0, 124.7, 121.4, 76.0, 66.9, 35.0, 21.1.