DIPEA (232 mg, 0.31 mL, 1.79 mmol) was added to a stirred solution of 2-amino-1-[4-(2-trifluoromethyl-benzoyl)-piperazin-1-yl]-ethanone hydrochloride salt (prepared by the method as described above) (190 mg, 0.54 mmol) in DMF (3 mL). HOBT (67 mg, 0.49 mmol) and EDCI (172 mg, 0.89 mmol) were then added at room temperature. After 2 minutes, 4-thiazol-5-yl-benzoic acid (100 mg, 0.49 mmol) (prepared by the method described above) was added and the resulting mixture was stirred at room temperature overnight. Cold water was then added and the product was extracted with EtOAc and the organic layer was washed with brine. The organic phase was dried over Na2SO4 and concentrated under reduced pressure to get the residue. The obtained residue was purified by column chromatography (using silica gel of 60-120 mesh and 70% EtOAc in Hexane as eluent) to afford 102 mg (45.33% yield) N-{2-Oxo-2-[4-(2-trifluoromethyl-benzoyl)-piperazin-1-yl]-ethyl}-4-thiazol-5-yl-benzamide. LCMS Purity: 97.53%. 1H NMR (CDCl3): δ 8.8 (s, 1H), 8.16 (s, 1H), 7.92-7.84 (d, 2H), 7.78-7.72 (d, 1H), 7.7-7.52 (m, 4H), 7.38-7.3 (d, 2H), 4.36-4.3 (m, 1H), 4.28-4.2 (m, 1H), 4.1-4.0 (d, 2H), 3.98-3.88 (m, 1H), 3.8-3.64 (m, 2H), 3.64-3.5 (d, 2H), 3.44-3.18 (t, 1H), 3.3-3.21 (bs, 2H).
