Boron tribromide → 4-{2-[4-(3,3-Dimethyl-butyl)-piperazin-1-yl]-2-oxo-ethoxy}-3-methyl-benzoic Acid

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Reaction Steps

1M Boron tribromide solution (2.66 ml, 2.66 mmol) was added dropwise to a solution of 4-{2-[4-(3,3-dimethyl-butyl)-piperazin-1-yl]-2-oxo-ethoxy}-3-methyl-benzoic acid methyl ester from Example E41.3 (500 mg, 1.33 mmol) in dichloromethane (20 ml) at 0° C. under an inert atmosphere. The mixture was stirred for 20 h at room temperature then cooled down to 0° C. 1M Boron tribromide solution (1.33 ml, 1.33 mmol) was added and the mixture was stirred for 2 h at room temperature. Solvents were re-moved in vacuo and azeotroped with toluene. The residue was purified by flash chromatography on silica gel (eluant; 1% acetic acid:5% methanol:94% chloroform) to yield the title compound (350 mg, 72%).

Provenance & Evidence