1H NMR (400 MHz, CDCl3) δ 7.34 (q, J = 7.9 Hz, 4H), 6.74 (d, J = 15.9 Hz, 1H), 5.99 (d, J = 15.9 Hz, 1H), 1.54 (s, 6H), 1.32 (s, 9H). 13C{1H} NMR (101 MHz, CDCl3) δ 151.33, 132.94, 129.61, 129.52, 126.26, 125.61, 123.54, 34.89, 34.60, 31.23, 27.72. HRMS (ESI) m/z calcd for C16H21NNa+ [M + Na]+: 250.1566, found 250.1568.