To a solution of 4-(5-trifluoromethyl-2,4-dioxo-3,4-dihydro-2H-pyrimidin-1-yl)-butyraldehyde (Prep24, 22 mg, 0.09 mmol) in dichloroethane (1 mL), (1S,5R)-1-(4-trifluoromethyl-phenyl)-3-aza-bicyclo[3.1.0]hexane (Prep4, 204 mg, 0.09 mmol), AcOH (7.9 mg, 0.13 mmol) and NaBH(AcO)3 (22 mg, 0.18) were added and the mixture was stirred at room temperature overnight. Ethyl acetate was added and the solution was washed with aqueous saturated NaHCO3. The organic phase was dried (Na2SO4) and evaporated. The crude was purified by flash chromatography with DCM-MeOH—NH4OH (95-5-1) to give the title compound (31 mg, 76% yield) as a free base.
