¹H NMR (400 MHz, CDCl₃) δ 9.74 (s, 1H), 7.34 (d, J = 8.1 Hz, 2H), 7.17 – 7.07 (m, 2H), 3.68 (s, 2H). ¹³C NMR (101 MHz, CDCl₃) δ 198.60, 130.90, 130.23, 129.08, 128.25, 49.73. GC-MS (m/z): 154。