To a solution of 2-[(4-(ethoxycarbonyl)piperazin-1-yl)carbonylmethyl](ethoxycarbonylmethyl)aminocarbonyl-4-methoxyquinoline (30 mg, 0.06 mmol) in ethanol (1.0 mL), was added a solution of LiOH (6 mg, 0.12 mmol) in water (1.0 mL). The resulting reaction mixture was stirred at ambient temperature for 1 hour. The reaction mixture was acidified to pH 3 by 2N NaHSO4, extracted by ethyl acetate (3×20 mL), dried over sodium sulfate, and concentrated in vacuo to afford 2-[(4-(ethoxycarbonyl)piperazin-1-yl)carbonylmethyl](carboxymethyl)aminocarbonyl-4-methoxyquinoline (25 mg) as a solid; NMR (DMSO-d6), 1.20 (m, 3), 3.20–3.60 (m, 8), 4.00–4.14 (m, 5), 4.20 (s, 1), 4.35 (s, 1), 4.50 (s, 1), 4.70 (s, 1), 7.23 (d, 1), 7.65 (m, 1), 7.80–7.94 (m, 2), 8.17 (m, 1) ppm.
