¹³C NMR (176 MHz, CDCl₃) δ 162.07 (s, 1C), 149.91 (s, 1C), 148.04 (s, 1C), 137.90 (s, 1C), 137.88 (s, 1C), 129.23 (s, 1C), 126.61 (s, 1C), 124.47 (s, 1C), 122.60 (s, 1C), 119.83 (s, 1C).