To a solution of 4-methoxy-2-carboxyquinoline (102 mg, 0.50 mmol) in CH2Cl2 (15 mL) was added triethylamine (0.33 mL, 2.36 mmol) and 1-hydroxybenzotriazole (HOBT) (80 mg, 0.60 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI) (110 mg, 0.60 mmol). After 5 minutes, 1-ethoxycarbonyl-4-(ethoxycarbonylmethyl)aminomethylcarbonylpiperazine (150 mg, 0.50 mmol) was added and the reaction mixture was stirred overnight. The reaction mixture was evaporated in vacuo to afford an oil, which was dissolved in ethyl acetate, and washed with saturated NaHCO3, 1M NaHSO4 and brine. The organic layer was evaporated in vacuo and the crude product was purified by flash column to afford 2-[(4-(ethoxycarbonyl)piperazin-1-yl)carbonylmethyl](ethoxycarbonylmethyl)aminocarbonyl-4-methoxyquinoline (30 mg).
