Trifluoroacetic acid → 2-(S)-[(5-Chloro-1H-pyrrolo[2,3-b]pyridine-2-carbonyl)amino]-3-(4-fluorophenyl)-propionic acid

Trifluoroacetic acid (1.9 mL, 24.3 mmol) was added to a suspension of 2-(S)-[(5-chloro-1H-pyrrolo[2,3-b]pyridine-2-carbonyl)amino]-3-(4-fluorophenyl)-propionic acid tert-butyl ester (EXAMPLE 281, 507 mg, 1.21 mmol) in DCM (25 mL) and the reaction mixture was stirred at rt for 16 h. Further trifluoroacetic acid (2 mL) was added and the reaction was stirred at rt for 48 h. The solvent was removed in vacuo and the solid partitioned between 1N hydrochloric acid (50 mL) and ethyl acetate (3×30 mL). The combined organic fractions were washed with brine (20 mL), dried (MgSO4) and concentrated in vacuo to give the title compound. δH (CD3OD)-3.11 (1H, dd), 3.33 (1H, dd), 4.88 (1H, m), 6.97 (2H, m), 7.06 (1H, s), 7.28 (2H, m), 8.08 (1H, d), 8.29 (1H, d); m/z (ES+)=362 [M+H]+; RT=3.67 min.