N-Bromosuccinamide → N-(5'-bromo-5-fluoro-3,4'-bipyridin-2'-yl)-N'-ethylurea

To a solution of N-ethyl-N′-(5-fluoro-3,4′-bipyridin-2′-yl)urea (Intermediate 29, 386 mg, 1.48 mmol) in DMF (7 mL), N-bromosuccinamide (396 mg, 2.22 mmol) was added. The resulting solution was heated to 80° C. and stirred at that temperature for 8 hours. The reaction mixture was partitioned between water and ethyl acetate. The layers were separated and the organic layer was washed with 5% sodium thiosulfate solution, water and brine. The organic layer was dried over sodium sulfate and concentrated under reduced pressure. The resulting solid was washed with acetonitrile and dried to give the title compound as an off-white solid (340 mg). MS (ESP): 340 (M+H+) for C13H12BrFN4O; NMR: 1.06 (t, 3H), 3.14 (q, 2H), 7.35 (t, 1H), 7.69 (s, 1H), 7.91-7.97 (m, 1H), 8.48 (s, 1H), 8.51 (t, 1H), 8.71 (d, 1H), 9.37 (s, 1H).