1H NMR (400 MHz, CDCl3) δ 7.20 (d, J = 8.0 Hz, 2H), 7.11 (d, J = 8.0 Hz, 2H), 6.73 (d, J = 15.4 Hz, 1H), 6.30 (d, J = 15.4 Hz, 1H), 2.39 (s, 3H), 2.33 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 136.41, 134.38, 129.30, 125.28, 124.92, 124.53, 21.10, 14.90. GC-MS (m/z): 164。