A mixture of Example 5C (55 mg, 0.20 mmol) and 1M LiOH (0.3 mL) in TBF (2 mL) was heated to 50° C., stirred for 3 hours, concentrated, dissolved in DMF (0.5 mL), and treated with a mixture of Example 3A (60 mg 0.20 mmol), EDCI (96 mg, 0.50 mmol), and DMAP (10 mg) in dioxane (2.0 mL). The mixture was stirred for 16 hours, diluted with ethyl acetate (50 mL), washed sequentially with 1M HCl (5 mL), water (5 mL), and brine (5 mL), dried (MgSO4), filtered, and concentrated. The concentrate was purified by flash column chromatography on silica gel, with 50% ethyl acetate/hexanes to provide a ˜2:1 mixture of diastereomers. MS (ESI(−)) m/e 540 (M−H)−; 1H NMR (400 MHz, DMSO-d6) δ 8.63 (2d, 1H total), 8.33 (2d, 1H total), 7.95 (m, 1H), 7.82 and 7.78 (2d, 2H total), 7.45 (m, 1H), 7.30 (m, 2H), 3.71 (m, 1H), 2.28-0.95 (m, 20H), 0.86 and 0.75 (2s, 9H total).
