¹³C NMR (176 MHz, DMSO) δ 160.61 (s, 1C), 151.06 (s, 1C), 148.36 (s, 1C), 141.52 (s, 1C), 138.52 (s, 1C), 137.31 (s, 1C), 127.01 (s, 1C), 122.89 (s, 1C), 121.51 (s, 1C), 121.24 (s, 1C), 119.87 (s, 1C), 113.49 (s, 1C), 111.19 (s, 1C).