¹³C NMR (176 MHz, CDCl₃) δ 170.83 (s, 1C), 145.04 (s, 1C), 136.04 (s, 1C), 129.72 (s, 1C), 129.27 (s, 1C), 128.84 (s, 1C), 127.85 (s, 1C), 127.04 (s, 1C), 126.62 (s, 1C), 38.54 (s, 1C).