Reaction Steps
Step 9 (C): (S)-2-((S)-3-acetamido-3-((R)-sec-butyl)-2-oxopyrrolidin-1-yl)-N-((1S,2S)-1-((2R,4S)-1-benzhydryl-4-phenoxypyrrolidin-2-yl)-3-(3,5-difluorophenyl)-1-hydroxypropan-2-yl)-4-phenylbutanamide. To a solution of (S)-2-((S)-3-acetamido-3-((R)-sec-butyl)-2-oxopyrrolidin-1-yl)-4-phenylbutanoic acid (Preparation A, 29 mg, 0.080 mmol) in DMF (2 mL) was added HATU (36.5 mg, 0.096 mmol). A solution of (1S,2S)-2-amino-1-((2R,4S)-1-benzhydryl-4-phenoxypyrrolidin-2-yl)-3-(3,5-difluorophenyl)propan-1-ol (Step 9 (B), 41.1 mg, 0.080 mmol) in DMF (2 mL) was then added, followed by N-methylmorpholine (37 μl, 0.336 mmol). The reaction mixture was stirred at rt for 3 h. pH 4 buffer was then added to quench. The mixture was extracted with ethyl acetate. The organic phase was washed with sat. aqueous NaCl, dried (MgSO4), and concentrated in vacuo. The crude mixture was purified by reverse phase Prep HPLC to give the title compound (34 mg): 1H NMR (CDCl3, 300 MHz) δ 0.82 (3H, d, J=6 Hz), 0.98 (3H, m), 1.07-1.15 (1H, m), 1.51-1.61 (1H, m), 1.68-1.74 (1H, m), 1.85-2.08 (5H, m), 2.17-2.30 (1H, m), 2.41-2.57 (2H, m), 2.63-2.76 (2H, m), 2.80-2.95 (3H, m), 3.09 (1H, dd, J=3, 15 Hz), 3.47-3.54 (3H, m), 3.67-4.05 (6H, m), 5.08 (1H, m), 5.39 (1H, s), 5.99 (1H, s), 6.56-6.69 (4H, m), 6.86 (2H, d, J=9 Hz), 7.03 (1H, m), 7.14-7.34 (12H, m), 7.68 (2H, m), 7.63-7.66 (2H, m). HPLC retention time: 1.99 min (method C). MS (ESI) (M+H)+ 857.45.
