Reaction Steps
To a mixture of compound 10A (1.0 g, 2.15 mmol) and BOC-D-Phg-OH (11A, 0.65 g, 2.58 mmol) was added anhydrous THF (30 mL) and the resultant mixture was stirred at rt for 5 min. DIPC (0.40 mL, 2.58 mmol) was added slowly at rt. The final reaction mixture was stirred at rt overnight. The solvent was removed and the residua were dissolved in small amount of ethyl acetate. Solid was removed by filtration. The filtrate was purified by silica column chromatography eluting with hexanes-ethyl acetate (v/v 3/1, 2/1, 1/1 and 2/3). The product was recrystallized from hexanes-ethyl acetate gave the title compound (12A, 0.81 g) as white crystals in 54% yield. 1H NMR (CDCl3, 500 MHz) δ 10.60 (s, 1H), 8.70 (s, 1H), 8.49 (s, 1H), 7.81 (d, 2H, J=8.0 Hz), 7.77 (s, 1H), 7.55 (d, 2H, J=8.0 Hz), 7.41 (m, 5H), 7.20 (d, 1H, J=8.5 Hz), 6.96 (d, 1H, J=9.0 Hz), 5.58 (d, 1H, J=3.5 Hz), 5.53 (d, 2H, J=3.5 Hz), 4.31 (s, 2H), 4.06 (d, 2H, J=3.5 Hz), 3.86 (d, 1H, J=13.0 Hz), 3.16 (t, 1H, J=13.0 Hz), 2.48 (d, 1H, J=13.5 Hz), 2.00 (s, 1H), 1.61 (br s, 2H), 1.56-1.30 (m, 11H), 0.88 (m, 1H). LCMS (ESI) m/z 720.27 (MNa+), 698.22 (MH+), 642.10, 598.15, 345.16 (100), 289.14. HPLC: tR=5.25 min.
