1H NMR (400 MHz, CDCl3) δ 7.48 (s, 1H), 7.40 (m, 1H), 7.30 (m, 2H), 5.43 (d, J = 30.8 Hz, 1H), 5.32 (s, 1H), 5.12 (s, 1H), 2.79 (s, 2H), 2.18 (s, 3H), 1.27 (s, 6H). 13C{1H} NMR (101 MHz, CDCl3) δ 143.92, 143.02, 141.52, 141.37, 128.24, 125.48, 124.92, 124.59, 123.56, 118.59, 112.76, 45.39, 33.14, 26.99, 21.81. HRMS (ESI) m/z calcd for C16H19NNa+[M+Na]+: 248.1410, found 248.1413.