To a solution in DMF (1.5 ml) of trans-4-[2-(4-furo[3,2-c]pyridin-4-yl-piperazin-1-yl)-ethyl]-cyclohexylamine trihydrochloride (intermediate A) (150 mg, 0.34 mmol) were added propionic acid (27 mg, 0.36 mmol), DIPEA (177 mg, 1.37 mmol) and TBTU (115 mg, 0.36 mmol). The reaction mixture was stirred over night at room temperature then sat. aq. NaHCO3 sol. was added and the product was extracted with EtOAc. After drying (Na2SO4) the solvent was evaporated and the product was purified by flash chromatography on silica gel (CH2Cl2/MeOH/25% NH3 aq 140:10:1) to yield the title compound as a white solid (123 mg, 93%), MS (ISP) m/z=385.3 [(M+H)+].
