A suspension of Intermediate 16d (165 mg, 0.234 mmol), Pd/C (10%, 16 mg), and 2M NH3 in MeOH (0.117 mL, 0.234 mmol) in EtOH (5 mL) under N2 was evacuated and purged with H2 twice, then stirred at rt for 8 h. The suspension was filtered through Celite, then the filter-cake washed with EtOH (10 mL). The combined organics were concentrated in vacuo to ˜0.5 mL volume, then applied to an SCX-2 cartridge (5 g) and washed with MeOH (5 mL). The product was eluted with 2M NH3 in MeOH (25 mL); concentration in vacuo left a pale yellow solid that was triturated with diethyl ether (10 mL) to leave a buff solid (121 mg). Half of this material was purified by HPLC(XBridge C18, 25-98% MeCN in H2O, 0.1% NH4OH) to give the title compound as a white solid after freeze-drying (20.0 mg, 15%). LCMS (Method 5): Rt 3.16 min, m/z 571 [MH+]. 1H NMR (400 MHz, d6-DMSO): 1.16 (9H, s), 1.33 (3H, d, J 6.8), 1.35 (3H, d, J 6.8), 1.68 (2H, m), 1.79 (2H, m), 1.91 (2H, m), 2.09 (2H, m), 2.47 (2H, m), 2.98 (2H, d, J 12.3), 3.50 (1H, sept, J 6.8), 3.92 (1H, m), 4.82 (1H, m), 5.51 (1H, t, J 4.5), 5.97 (1H, s), 6.88 (1H, d, J 8.6), 7.14 (1H, dd, J 9.9, 2.1), 7.26 (1H, m), 7.31-7.38 (3H, m), 7.65 (1H, dd, J 9.8, 0.8), 8.07 (1H, br s), 8.18 (1H, d, J 2.0).
