¹H NMR (700 MHz, CDCl₃) δ 8.48 (s, 1H), 8.35 (d, J = 8.1 Hz, 1H), 7.40 (t, J = 7.5 Hz, 1H), 7.35 (q, J = 6.3 Hz, 1H), 7.07 (m, J = 7.1 Hz, 1H), 6.99 (t, J = 7.5 Hz, 1H), 3.77 (s, 1H), 2.33 (s, 1H).