1H NMR (400 MHz, CDCl3) δ 7.36 (d, J = 7.8 Hz, 2H), 7.29 (s, 5H), 7.20 (s, 1H), 7.12 (d, J = 7.9 Hz, 1H), 6.94 (d, J = 7.9 Hz, 2H), 6.82 (d, J = 8.0 Hz, 1H), 3.87 (s, 6H). 13C NMR (101 MHz, CDCl3) δ 196.09, 161.01, 160.49, 156.24, 136.83, 133.30, 131.39, 130.64, 130.22, 129.90, 128.07, 127.33, 125.06, 122.25, 116.12, 114.15, 110.42, 55.82, 55.31