1H NMR (400 MHz, CDCl3) δ 8.24-8.17 (m, 4H), 7.88 (d, J = 8.5 Hz, 1H), 7.84 (d, J = 8.1 Hz, 1H), 7.74 (t, J = 7.5 Hz, 1H), 7.56-7.48 (m, 4H).13C NMR (100 MHz, CDCl3) δ 157.5, 148.3, 139.7, 137.0, 129.9, 129.5, 129.2, 129.0, 127.7, 127.6, 127.3, 126.5, 119.1.