1H NMR (400 MHz, CDCl3) δ 7.39 (t, 2H), 7.34-7.30 (m, 2H), 7.29-7.23 (m, 1H), 6.37 (s, 1H), 1.99 (s, 3H), 1.95 (s, 3H);13C{H} NMR (101 MHz, CDCl3) δ 138.7, 135.3, 128.7, 128.0, 125.7, 125.2, 26.8, 19.3。