Following the procedure described in Example 4, except using the material from Example 20 (77 mg, 0.169 mmol), (S)-2-amino-N-((S)-1-((S)-1-amino-3-(4-hydroxyphenyl)-1-oxopropan-2-ylamino)-1-oxopropan-2-yl)propanamide (61.2 mg, 0.19 mmol), EDC (56.2 mg, 0.293 mmol), 1-hydroxy-7-azabenzotriazole (19.2 mg, 0.141 mmol), anhydrous DMF (2 mL) and N-methylmorpholine (104 μL, 0.946 mmol), 67 mg (54.5%) of the title compound is obtained as a yellow solid as a TFA salt. Purification is done by preparative HPLC (Condition A) using a PHENOMENEX® Luna Axia 30×100 mm S10 column from 15% Solvent B to 90% Solvent B over 1 min, ret. T=6.98 min.
