1H NMR (400 MHz, CDCl3) δ 7.25 (t, J = 5.9 Hz, 2H), 6.92 (t, J = 7.9 Hz, 2H), 6.62 (d, J = 15.9 Hz, 1H), 5.85 (d, J = 15.9 Hz, 1H), 1.43 (s, 6H). 13C{1H} NMR (101 MHz, CDCl3) δ 162.44 (d, J = 247.6 Hz), 131.81 (d, J = 3.2 Hz), 130.08 (d, J = 2.0 Hz), 128.56, 128.04 (d, J = 8.1 Hz), 123.25, 115.50 (d, J = 21.7 Hz), 34.78, 27.50. GC-MS (m/z) = 189.