1H NMR (600 MHz, DMSO‑d 6) δ 8.38 (s, 1H), 8.34 (s, 1H), 8.15 (s, 1H), 8.14 (s, 1H), 7.36 (br.s, 2H), 7.29 (br. s, 2H), 5.97 (d, J = 6.4 Hz, 1H), 5.85 (d, J = 5.9 Hz, 1H), 5.58–4.98 (m, 4H), 4.70–4.63 (m, 1H), 4.52 (dd, J = 6.4 Hz, J = 4.7 Hz, 1H), 4.33 (dd, J = 4.7 Hz, J = 2.6 Hz, 1H), 4.12 (dd, J = 5.2 Hz, J = 3.8 Hz, 1H), 4.02–3.93 (m, 2H), 3.70–3.48 (m, 4H), 2.86–2.58 (m, 4H).