DIPEA (0.084 mL, 0.49 mmol) was added drop wise to 4-benzenesulfonyl-benzoic acid (51 mg, 0.20 mmol) in DMF (5 mL). EDCI (78 mg, 0.41 mmol) and HOBT (26 mg, 0.20 mmol) were added consecutively and, after 10 mins, 2-amino-1-[4-(2-trifluoromethyl-benzoyl)-piperazin-1-yl]-ethanone in its TFA salt form (70 mg, 0.16 mmol) was added. The resulting mixture was stirred at room temperature overnight. Water was then added and the resulting solid was filtered to afford 60 mg (65% yield) of 4-benzenesulfonyl-N-{2-oxo-2-[4-(2-trifluoromethyl-benzoyl)-piperazin-1-yl]-ethyl}-benzamide. LC-MS purity: 95.5%. 1H NMR (DMSO-D6): δ 8.8 (t, 1H), 8.1 (m, 5H), 7.8 (m, 6H), 7.6 (m, 1H), 4.2 (d, 2H), 3.6 (m, 6H), 3.2 (m, 2H).
