A mixture of N-(3,4-dichlorophenyl)-1-[(3R)-piperidin-3-ylmethyl]piperidine-4-carboxamide (100 mg), potassium carbonate (41 mg) and ethyl bromide (0.022 mL) in dimethylformamide (4 ml) was stirred at room temperature for 24 hours. The reaction mixture was partitioned between dichloromethane and water. The organic layer was separated, dried over magnesium sulfate and evaporated. The residue was purified by silica column chromatography, eluting with a gradient of 0 to 10% 7M NH3/MeOH in dichloromethane to give the title compound as a white solid (80 mg, 74%).
