1H NMR (400 MHz, CDCl3) δ 8.15-8.21 (m, 4H), 7.81 (d, J = 8.3 Hz, 2H), 7.73 (t, J = 7.7 Hz, 1H), 7.52 (t, J = 7.5 Hz, 1H), 7.20 (t, J = 8.1 Hz, 2H). 13C NMR (100 MHz, CDCl3) δ 163.8 (d, J = 249.0 Hz), 156.2, 148.2, 136.9, 135.8 (d, J = 3.2 Hz), 129.8, 129.6, 129.4 (d, J = 8.4 Hz), 127.5, 127.1, 126.4, 118.6, 115.8 (d, J = 21.6 Hz).
