¹H NMR (400 MHz, CDCl₃) δ 7.20-7.12 (m, 8H), 7.12-7.08 (m, 1H), 6.83 (d, J = 8.0 Hz, 2H), 6.78 (d, J = 8.2 Hz, 2H), 2.37 (s, 3H), 2.20 (s, 3H), 2.14 (s, 3H); ¹³C{H} NMR (101 MHz, CDCl₃) δ 144.4, 140.8, 140.3, 139.1, 136.0, 135.2, 134.8, 130.7, 129.9, 129.3, 128.7, 128.1, 127.8, 126.0, 23.4, 21.2, 21.0; HRMS (EI) m/z [M]⁺ Calcd for C₂₃H₂₂: 298.1722; Found: 298.1725。