1H NMR (700 MHz, CDCl3) δ 8.69 (d, J = 1.6 Hz, 1H), 8.34 (s, 1H), 7.41 (t, J = 7.5 Hz, 1H), 7.35 (q, J = 2.6 Hz, 1H), 7.25 (t, J = 4.7 Hz, 1H), 7.10 (d, J = 8.3 Hz, 1H), 3.79 (s, 1H), 2.35 (s, 1H).