1H NMR (400 MHz, CDCl3) δ 7.28 – 7.16 (m, 3H), 7.11 (d, J = 7.0 Hz, 1H), 6.75 (d, J = 15.9 Hz, 1H), 6.04 (d, J = 15.9 Hz, 1H), 2.37 (s, 3H), 1.55 (s, 6H). 13C{1H} NMR (101 MHz, CDCl3) δ 138.15, 135.57, 130.07, 129.78, 128.82, 128.48, 127.14, 123.63, 123.37, 34.80, 27.56, 21.25. HRMS (ESI) m/z calcd for C13H15NNa+ [M+Na]+: 208.1097, found 208.1093.