1H NMR (400 MHz, CDCl3) δ 9.88 (s, 1H), 7.13 (d, J = 7.6 Hz, 4H), 6.91 (d, J = 7.5 Hz, 4H), 4.79 (s, 1H), 3.80 (s, 6H). 13C NMR (101 MHz, CDCl3) δ 198.72, 158.99, 130.13, 128.50, 114.40, 62.49, 55.28. GC-MS (m/z): 256。