1H NMR (600 MHz, D2O) δ 8.11 (s, 1H), 8.05 (s, 1H), 7.98 (s, 1H), 7.86 (s, 1H), 5.89 (d, J = 2.5 Hz, 1H), 5.77 (d, J = 3.3 Hz, 1H), 4.51–4.47 (m, 2H), 4.36 (dd, J = 5.1 Hz, J = 3.4 Hz, 1H), 4.34–4.29 (m, 1H), 4.14–4.08 (m, 2H), 3.97 (td, J = 10.6 Hz, J = 2.4 Hz, 1H), 3.89–3.80 (m, 3H), 3.71 (dd, J = 13.0, J = 3.4 Hz, 1H), 3.15–3.04 (m, 2H), 3.03–2.81 (m, 2H), 2.76 (d, J = 14.2 Hz, 1H), 2.58 (d, J = 13.8 Hz, 1H), 2.14–1.99 (m, 2H).