5-fluoro-3,4-dihydro-1,8-naphthyridin-2(1H)-one (Int-28, 120 mg, 0.72 mmol), 6-hydroxyquinoline-3-carboxylic acid (1.5 mg, 0.794 mmol), and cesium carbonate (706 mg, 2.17 mmol) were weighed into a microwave vial. N,N-Dimethylformamide (3.5 mL) was added and the vial was sealed and heated in a microwave at 150° C. for 4 h. The vial was opened and water was added (5 mL). The resulting clear solution was neutralized by the addition of 1N HCl and washed with ethyl acetate. The washed aqueous phase was acidified to pH 3 and pure product was collected by suction filtration. LC-MS: (FA) ES+ 336; 1H NMR (400 MHz, d6-DMSO) δ ppm 13.55 (s, 1H), 10.60 (s, 1H), 9.27 (d, J=2.1 Hz, 1H), 8.94 (d, J=1.9 Hz, 1H), 8.17 (d, J=9.1 Hz, 1H), 8.07-8.02 (m, 1H), 7.85 (d, J=2.7 Hz, 1H), 7.74 (dd, J=9.1, 2.8 Hz, 1H), 6.52 (d, J=5.7 Hz, 1H), 2.92 (t, J=7.7, 7.7 Hz, 2H), 2.54 (dd, J=8.3, 7.1 Hz, 2H).
