¹³C NMR (176 MHz, CDCl₃) δ 167.48 (s, 1C), 138.31 (s, 1C), 134.52 (s, 1C), 131.70 (s, 1C), 128.94 (s, 1C), 128.74 (s, 1C), 128.07 (s, 1C), 127.78 (s, 1C), 127.09 (s, 1C), 44.28 (s, 1C).