A mixture of Example 16 (half crude material, assume 64.8 mg, 0.114 mmol) and formaldehyde (37% in water, 0.092 mL, 1.14 mmol) in DCM (2 mL) was stirred at RT for 10 min, then AcOH (0.013 mL, 0.227 mmol) and NaBH(OAc)3 (48.1 mg, 0.227 mmol) were added sequentially, and the solution stirred at RT for 3 h. The solution was concentrated in vacuo to ˜0.5 mL volume, applied to an SCX-2 cartridge (2 g) and washed with MeOH (15 mL). The product was eluted with 2M NH3 in MeOH (10 mL); concentration in vacuo left a pale yellow solid (82.6 mg). HPLC (XBridge C18, 30-98% MeCN in H2O, 0.1% NH4OH) gave the title compound as a white solid after freeze-drying (30.8 mg, 46%). LCMS (Method 5): Rt 3.18 min, m/z 585 [MH+]. 1H NMR (400 MHz, d6-DMSO): 1.21 (9H, s), 1.38 (H, d, J 6.8), 1.40 (3H, d, J 6.8), 1.75 (2H, t, J 12.2), 1.91-2.04 (6H, m), 2.07-2.17 (2H, m), 2.18 (3H, s), 2.87 (2H, d, J 10.6), 3.58 (1H, sept, J 6.8), 3.88 (1H, m), 4.88 (1H, m), 5.56 (1H, t, J 4.7), 6.02 (1H, s), 6.89 (1H, d, J 8.6), 7.19 (1H, dd, J 9.8, 2.1), 7.31 (1H, m), 7.36-7.43 (3H, m), 7.70 (1H, d, J 9.8), 8.06 (1H, s), 8.22 (1H, d, J 2.0).
