1H NMR (700 MHz, CDCl3) δ 7.79 (d, J = 7.6 Hz, 5H), 7.50 (t, J = 7.3 Hz, 3H), 7.43 (t, J = 7.6 Hz, 6H), 7.36 (d, J = 4.3 Hz, 10H), 7.30 (m, J = 4.2 Hz, 3H), 6.46 (s, 1H), 4.65 (d, J = 5.6 Hz, 5H).