To a solution of 50 mg of 5-chloro-2-isopropylamino-benzoic acid (0.23 mmol) and 81 mg (0.23 mmol) of (4-cyclopentyl-benzyl)-[2-(3-trifluoromethyl-phenyl)-ethyl]-amine in 4 ml of DMF were added 75 mg of TBTU (0.23 mmol) and 0.2 ml (1.17 mmol) of N,N-di-isopropylethyl amine. After stirring the reaction mixture over night at RT it was diluted with 50 ml water and extracted with ethyl acetate. The combined organic phases were washed with 10%-aqueous KHCO3 solution, 0.1M HCl solution and brine, dried with magnesium sulfate, filtered and concentrated in vacuo. The remaining oil was purified by column chromatography (silica gel; heptane 100% to heptane/EtOAc 4:1) to give 90 mg (71%) of a colorless oil. MS (ISP) 543.5 (M+H)+.
