1H NMR (400 MHz, CDCl3) δ 7.72-7.28 (m, 9H), 6.01 (d, J = 1.5 Hz, 1H), 5.45 (d, J = 1.5 Hz, 1H), 2.32 (s, 3H). 13C{H}NMR (101 MHz, CDCl3) δ 149.5, 141.6, 140.6, 136.0, 130.0, 130.0, 128.3, 127.5, 127.5, 126.4, 125.7, 114.7, 20.1。