A mixture of (R)-3-[N-(5′-chloro-2′-fluorobiphenyl-4-ylmethyl)-N′-(3-methoxyisoxazole-5-carbonyl)hydrazino]-2-hydroxypropionic acid (20.0 mg, 43 mmol), EDC (45.8 μL, 259 μmol) and HOBt hydrate (39.6 mg, 259 μmol) in DCM (0.5 mL, 8 mmol) was stirred at room temperature for 10 minutes. 4-Morpholineethanol (41.8 μL, 345 μmol) was added, and the resulting mixture was stirred at room temperature overnight. The mixture was concentrated and the residue was dissolved in AcOH (1.5 mL), filtered, and purified by reverse phase preparative HPLC to yield the title compound (14.1 mg) as a TFA salt. MS m/z [M+H]+ calc'd for C22H39ClFN4O2, 577.18. found 577.
