¹H NMR (400 MHz, CDCl₃) δ 8.83 (d, J = 2.1 Hz, 2H), 8.04 (d, J = 2.2 Hz, 1H), 7.29 (s, 4H), 7.09 (s, 2H), 2.44 (s, 12H). ¹³C{H} NMR (101 MHz, CDCl₃) δ 146.6, 138.5, 137.6, 136.6, 132.7, 129.6, 125.0, 21.2. HRMS (EI) m/z: [M]⁺ Calcd for C₂₁H₂₁N 287.1674; Found: 287.1677。