¹H NMR (400 MHz, CDCl₃) δ 9.71 (s, 1H), 7.47 – 7.08 (m, 4H), 3.71 (d, J = 1.8 Hz, 2H), 2.29 (s, 3H). ¹³C NMR (101 MHz, CDCl₃) δ 199.15, 137.07, 130.55, 130.53, 130.43, 127.69, 126.40, 48.65, 19.62. GC-MS (m/z): 134。