A mixture of methyl 5-methyl-2-nitrobenzoate (35.0 g, 179 mmol), N-bromosuccinimide (33.5 g, 188 mmol), and azobisisobutyronitrile (500 mg) in carbon tetrachloride (450 mL) was refluxed for 14 h. The insoluble material formed was removed by filtration and the filtrate was concentrated. The residue was dissolved in DMF (300 mL) and potassium phthalimide (19.41 g, 45 mmol) was added. The mixture was stirred for 2 h at 50° C., poured into brine, and extracted with a 1:1 mixture of toluene and ethyl acetate. The organic layers were washed with brine, dried over magnesium sulfate, and concentrated. The residue was purified by silica gel column chromatography with 4:1 to 2:1 hexane/ethyl acetate to give 20.0 g of the title compound (33%).
