To a suspension of the product from Example 441D (200 mg, 0.41 mmol) and O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium tetrafluoroborate [TBTU] (187 mg, 0.57 mmol) in DMSO (2 mL) was added the product of Example 438C (178 mg, 0.57 mmol) then N,N-diisopropylethylamine (0.220 mL, 1.10 mmol) dropwise at room temperature under N2. After 2 hours the reaction was quenche with water (20 mL) and extracted with ethyl acetate (75 mL). The organic layer was washed sequentially with water (3×) and saturated aqueous NaHCO3, dried over MgSO4, and concentrated. The residue was purified by silica gel column chromatography eluting with ethyl acetate to give the title compound as a pale yellow amorphous solid (245 mg., 79%).
