1H NMR (400 MHz, CDCl3) δ 7.60 (d, J = 6.9 Hz, 1H), 7.44 (s, 5H), 7.38 (d, J = 7.3 Hz, 1H), 7.30 (d, J = 9.3 Hz, 3H), 7.25 (d, J = 7.8 Hz, 2H), 7.14 (d, J = 7.1 Hz, 1H), 1.31 (s, 9H). 13C NMR (101 MHz, CDCl3) δ 196.85, 154.65, 150.73, 145.57, 133.41, 133.03, 132.20, 131.15, 130.79, 129.56, 129.13, 128.78, 128.51, 127.67, 125.04, 122.90, 121.08, 34.62, 31.24.