13C NMR (150 MHz, DMSO‑d 6) δ 156.1, 156.0, 152.5 (2C), 149.3, 148.9, 147.2, 140.1, 139.8, 139.6, 133.7, 131.0, 125.0, 122.9, 119.3, 119.2, 87.8, 86.2, 86.1, 82.2, 81.3, 72.4, 71.8, 68.9, 68.1, 61.3, 56.8, 56.0, 53.0.