1H NMR (500 MHz, CDCl3) δ 8.32 (s, 1H), 8.31 (s, 1H), 8.17 (s, 1H), 7.93 (s, 1H), 6.17–6.06 (m, 5H), 6.03 (d, J = 2.9 Hz, 1H), 5.39 (dd, J = 6.5 Hz, J = 3.0 Hz, 1H), 4.99–4.92 (m, 1H), 4.51–4.45 (m, 1H), 4.33–4.25 (m, 2H), 4.08 (dt, J = 5.6 Hz, J = 3.2 Hz, 1H), 3.98 (dd, J = 11.5 Hz, J = 3.6 Hz, 1H), 3.75 (dd, J = 11.6 Hz, J = 2.8 Hz, 1H), 3.71–3.63 (m, 2H), 2.95–2.69 (m, 4H), 1.61 (s, 3H), 1.37 (s, 3H), 0.92 (s, 9H), 0.88 (s, 9H), 0.13–0.04 (m, 12H).