Oxalyl chloride → 4-{3-[4-(3,3-Dimethyl-butyl)-piperazin-1-yl]-3-oxo-propyl}-3-methyl-benzoic Acid Methyl Ester

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Reaction Steps

Oxalyl chloride (2.6 ml, 30 mmol) was added slowly to a solution of 4-(2-carboxy-ethyl)-3-methyl-benzoic acid methyl ester from Example E30.3 (5.33 g, 24 mmol) in di-chloromethane (60 ml) and few drops of DMF at 0° C. The mixture was stirred for 2 h at room temperature then concentrated in vacuo and azeotroped with toluene. The residue was dissolved in dichloromethane (30 ml) and added to a solution of 1-(3,3-dimethyl-butyl)-piperazine hydrochloride from Example E4 (6.3 g, 26 mmol) in dichloromethane (45 ml) and DIEA (17 ml, 96 mmol) at 0° C. The mixture was stirred for 1 h at room temperature then concentrated in vacuo. The residue was purified by flash chromatography on silica gel (eluant; 5% methanol:95% dichloromethane) to yield the title compound (8.5 g, 96%).

Provenance & Evidence