To a solution of (2S)-2-[[[4-(2-amino-7-chloro-4-quinolinyl)-1-piperazinyl]carbonyl]amino]-propanoic acid (˜30 mg), 4-fluoroanaline (0.03 mL, 0.32 mmol), Et3N (0.14 mL, 0.35 mmol) in DMF (2 mL) was added HATU (133 mg, 0.35 mmol) at rt. After stirring at rt overnight, the reaction mixture was poured into ice-water. The crude solid was obtained by filtration and re-dissolved in CH2Cl2-MeOH, dried over Na2SO4. Concentration in vacuo followed by preparative TLC(CH2Cl2-MeOH-Et3N, 9:1:1%) afforded the title product as a light yellow powder. LC-MS: 471 (M++1). 1H NMR (DMSO-d6): δ 1.30 (d, 3H), 3.00 (br.s, 4H), 3.58 (m, 4H), 4.28 (m, 1H), 6.26 (s, 1H), 6.60 (br.s, 2H), 6.30 (d, 1H), 7.16 (m, 3H), 7.40 (d, 1H), 7.63 (dd, 2H), 7.75 (d, 1H).
