¹³C NMR (176 MHz, DMSO) δ 171.26 (s, 1C), 139.62 (s, 1C), 139.14 (s, 1C), 132.72 (s, 1C), 129.26 (s, 1C), 129.16 (s, 1C), 128.98 (s, 1C), 128.21 (s, 1C), 127.27 (s, 1C), 127.12 (s, 1C), 126.73 (s, 1C), 70.51 (s, 1C), 41.95 (s, 1C).