1H NMR (400 MHz, CDCl3) δ 7.59 (d, J = 6.9 Hz, 1H), 7.44 (s, 5H), 7.38 (t, J = 7.7 Hz, 1H), 7.28 (dd, J = 13.0, 7.7 Hz, 3H), 7.13 (d, J = 7.2 Hz, 1H), 6.83 (d, J = 8.4 Hz, 2H), 3.81 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 196.97, 159.24, 153.82, 145.59, 133.44, 133.07, 131.92, 131.27, 130.76, 129.12, 128.81, 128.65, 128.50, 123.12, 122.87, 120.95, 113.67, 55.19.