1H NMR (400 MHz, CDCl3) δ 7.27 (s, 1H), 7.13 (s, 7H), 7.07 (d, J = 7.5 Hz, 2H), 7.03 (d, J = 7.2 Hz, 1H), 6.92 (d, J = 7.3 Hz, 1H), 2.27 (s, 3H), 2.25 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 196.82, 155.78, 142.44, 139.42, 139.20, 133.22, 131.51, 131.27, 131.15, 129.94, 129.88, 129.42, 128.49, 128.02, 127.48, 123.97, 121.17, 21.51, 21.38.