NMR:
1H-NMR (400 MHz, DMSO-d6) δ 10.36 (s, 1H), 10.16 (s, 1H), 8.25 (d, J = 1.5 Hz, 1H), 7.88 (d, J = 8.8 Hz, 1H), 7.69 (dd, J = 8.8, 1.6 Hz, 1H), 7.18 (ddd, J = 8.6, 6.1, 2.1 Hz, 1H), 7.05 – 6.91 (m, 1H), 4.25 (s, 3H);
13C-NMR (101 MHz, Chloroform-d) δ 187.15, 150.29 (dd, J = 245.0, 10.8 Hz), 142.79 (dd, J = 248.3, 11.3 Hz), 142.47 , 140.75 , 139.76 (d, J = 14.4 Hz), 133.44 , 129.52 , 127.17, 125.88 – 124.97 (m), 121.70 , 121.40 , 111.08 , 107.71 (d, J = 16.7 Hz), 37.18.
