Following method C with 24 (40 mg, 0.42 μmol, 1.00 eq) and a 0–50% linear gradient of acetonitrile in TEAAc buffer 50 mM, pH 7 for purification, 6 (8 mg, 28%) was obtained as a white powder with 99% purity determined by HPLC analysis at 260 nm. 1H NMR (500 MHz, DMSO‑d 6) δ 8.36 (s, 1H), 8.32 (s, 1H), 8.14 (s, 1H), 8.13 (s, 1H), 7.33 (br. s, 2H), 7.25 (br. s, 2H), 5.97 (d, J = 6.3 Hz, 1H), 5.85 (d, J = 5.2 Hz, 1H), 5.49–5.39 (m, 3H), 5.14 (d, J = 5.3 Hz, 1H), 4.62 (q, J = 5.4 Hz, 1H), 4.52 (dd, J = 6.5, 4.7 Hz, 1H), 4.29 (dd, J = 4.8, 2.8 Hz, 1H), 4.06 (q, J = 4.9 Hz, 1H), 4.00–3.92 (m, 2H), 3.68–3.46 (m, 4H), 2.79 (dd, J = 14.0, 4.6 Hz, 1H), 2.70–2.51 (m, 3H), 2.41–2.30 (m, 2H), 1.22 (q, J = 7.4, 2H), 1.07 (tdd, J = 13.4 Hz, J = 10.5 Hz, J = 6.3 Hz, 2H), 0.73 (t, J = 7.3 Hz, 2H). 13C NMR (125 MHz, DMSO‑d 6) δ 156.1, 156.0, 152.5, 152.4, 149.3, 149.0, 139.8, 139.8, 119.3, 119.2, 87.6, 86.3, 86.2, 82.4, 81.2, 72.5, 71.9, 69.2, 68.0, 62.0, 56.2, 54.0, 53.7, 28.3, 19.8, 13.8. HRMS (ESI+): m/z calcd for C26H38N11O7 [M+H]+: 616.2956, Found 616.2955.