1H NMR (400 MHz, CDCl3) δ 9.12 (s, 1H), 8.92 (d, J = 31.4 Hz, 2H), 7.49 – 7.26 (m, 2H), 7.13 (d, J = 38.4 Hz, 1H). 13C NMR (101 MHz, CDCl3) δ 157.23, 153.46, 138.43, 136.24, 128.62, 127.32, 125.31.