“…1 H NMR (500 MHz, CDCl 3 ): δ 8.46 (s, 1H), 8.19−8.16 (m, 1H), 7.93 (d, J = 7.8 Hz, 1H), 7.55 (t, J = 8.0 Hz, 1H), 7.34−7.30 (m, 3H), 7.22−7.19 (m, 2H), 7.12 (d, J = 3.1 Hz, 1H), 6.59 (d, J = 9.3 Hz, 2H), 6.53 (d, J = 9.3 Hz, 2H), 5.71 (dd, J = 8.4, 2.9 Hz, 1H), 5.55 (s, 1H), 4.79 (dd, J = 9.3, 8.4 Hz, 1H) 4.52 (dd, J = 9.3, 2.9 Hz, 1H), 3.68 (s, 3H) ppm. 13…”