1H NMR (400 MHz, CDCl3) δ 10.32 (d, J = 8.8 Hz, 1H), 9.29 (t, J = 8.9 Hz, 1H), 7.84 (t, J = 8.0 Hz, 1H), 7.50 (dd, J = 8.6, 7.4 Hz, 1H), 7.45 – 7.39 (m, 2H), 7.36 – 7.28 (m, 2H), 7.05 (dd, J = 11.9, 5.3 Hz, 2H), 3.90 (d, J = 8.8 Hz, 3H), 3.78 (d, J = 8.7 Hz, 3H). 13C NMR (101 MHz, CDCl3) δ 193.47, 159.49, 158.06, 145.83, 134.23, 133.81, 132.38, 130.75, 130.32, 126.74, 126.59, 126.36, 120.51, 113.98, 105.71, 55.35, 55.14.