A mixture of methyl 3-nitro-2-(bromomethyl)benzoate (2.5 g, 9.12 mmol), L-glutamic acid dibenzyl ester p-toluenesulfonate salt (3.0 g, 9.12 mmol) and triethylamine (2.0 g, 20.0 mmol) in THF (50 mL) is heated at reflux for 16 hours. The mixture is diluted with methylene chloride (150 mL) and washed with water (2×40 mL), brine (40 mL), dried and concentrated to an oil. The oil is purified by chromatography (silica gel, Hexane:ethoxyacetic acid 7:3) to give 1-(4-nitro-1-oxoisoindolin-2-yl)propane-1,3-dicarboxylic acid dibenzyl ester (2.65 g, 59%); 1H NMR (CDCl3) δ8.39 (d, J=7.8 Hz, 1H), 8.16 (d, J=7.3 Hz, 1H), 7.69 (t, J=7.9 Hz, 1H), 7.30 (m, 10H), 5.29 (s, 2H), 5.29-5.13 (m, 1H), 5.03 (s, 2H), 4.98 (d, J=19.1 Hz, 1H), 4.85 (d, J=19.2 Hz, 1H), 2.54-2.39 (m, 4H); 13C NMR (CDCl3) δ171.79, 169.92, 166.72, 143.47, 137.25, 135.49, 135.04, 134.99, 130.17, 129.67, 128.62, 128.52, 128.29, 128.25, 128.23, 127.04, 67.49, 66.58, 53.70, 48.35, 30.87, 24.79.
