A solution of N-(4-aminophenyl)isoindoline-2-carboxamide (100 mg, 0.395 mmol), 4-phenylbutanoic acid (78 mg, 0.474 mmol), 1-hydroxybenzotriazole hydrate (66.5 mg, 0.434 mmol) and N-methylmorpholine (0.109 ml, 0.987 mmol) in dimethylformamide (1.771 ml) at room temperature was treated with N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (136 mg, 0.711 mmol). The mixture was stirred overnight and diluted with water (10 ml); the resulting suspension was filtered with water washes to give product with an impurity. This solid was suspended in 2% methanol/methylene chloride and filtered to provide the title compound. 1H NMR (300 MHz, DMSO-d6) δ ppm 1.78-2.00 (m, 2H), 2.30 (t, J=7.3 Hz, 2H), 2.62 (t, J=7.5 Hz, 2H), 4.75 (s, 4H), 7.08-7.41 (m, 9H), 7.46 (s, 4H), 8.26 (s, 1H), 9.73 (s, 1H); (ESI(+)) m/e 400 (M+H)+.
