To a stirred solution at 0° C. of provide 3-cyanopropanoic acid (0.110 g, 1.11 mmol) and DMF (2 drops) in THF (4.0 mL) was added oxalyl chloride (0.144 g, 1.13 mmol) dropwise and the reaction mixture was warmed to room temperature. After 1 h the reaction mixture was concentrated under reduced pressure. To a stirred solution at 0° C. of 1-(2-tert-butylphenyl)piperazine (0.218 g, 1.00 mmol) and triethylamine (0.303 g, 3.00 mmol) in methylene chloride (2.0 mL) was added a solution of the freshly prepared 3-cyanopropanoyl chloride in methylene chloride (2.0 mL) and the reaction mixture was warmed to room temperature. After 2 h the reaction mixture was diluted with methylene chloride (10.0 mL), washed with water (20.0 mL), dried (Na2SO4), filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography (silica gel, 50% ethyl acetate/heptanes) to provide 4-(4-(2-tert-butyl-phenyl)piperazin-1-yl)-4-oxobutanenitrile (0.170 g, 57%) as an off-white solid, mp 109-110° C.
