DIPEA (83 mg, 0.11 mL, 0.21 mmol) was added to a stirred solution of 2,4-difluoro-biphenyl-4-carboxylic acid (50 mg, 0.21 mmol) in DMF (1 mL). HOBT (35 mg, 0.25 mmol) and EDCI (50 mg, 0.25 mmol) were then added at room temperature. After 2 minutes 2-amino-1-[4-(2-trifluoromethyl-benzoyl)-piperazin-1-yl]-ethanone hydrochloride salt (90 mg, 0.25 mmol) was added and the resulting mixture was stirred at room temperature overnight. Cold water was then added and then extrated with ethyl acetate. The organic layer was washed with brine and dried over Na2SO4 and concentrated under reduced pressure to afford 56.9 mg (50.35%) of 2,4-difluoro-biphenyl-4-carboxylic acid {2-oxo-2-[4-(2-trifluoromethyl-benzoyl)-piperazin-1-yl]-ethyl}-amide. LCMS Purity: 95.42%. 1H NMR (DMSO-d6): δ 8.2-7.94 (d, 2H), 7.88-7.74 (m, 2H), 7.74-7.6 (m, 4H), 7.6-7.5 (m, 1H), 7.46-7.34 (m, 1H), 7.3-7.2 (m, 1H), 4.3-4.1 (m, 2H), 3.8-3.4 (m, 6H), 3.2-3.0 (m, 2H).
