¹³C NMR (176 MHz, CDCl₃) δ 173.40 (s, 1C), 154.76 (s, 1C), 151.72 (s, 1C), 147.69 (s, 1C), 138.69 (s, 1C), 120.00 (s, 1C), 114.55 (s, 1C), 79.82 (s, 1C), 44.30 (s, 1C), 43.60 (s, 1C), 42.86 (s, 1C), 28.55 (s, 1C).