Cesium carbonate → Ethyl 6'-{[(ethylamino)carbonyl]amino}-5''-fluoro-3,3':4',3''-terpyridine-5-carboxylate

N-(5′-bromo-5-fluoro-3,4′-bipyridin-2′-yl)-N′-ethylurea (Intermediate 30, 0.34 g, 1.00 mmol), ethyl 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)nicotinate (Oakwood Products, Inc., Cat. #021607) (0.306 g, 1.10 mmol), tetrakis triphenyl phosphine palladium (0.058 g, 0.05 mmol), and cesium carbonate (0.359 g, 1.10 mmol) were added to a microwave vial and degassed with nitrogen. A solution of 1,4-dioxane:water (4:1, 10 mL) was added to the solution and the reaction mixture was heated to 100° C. for 30 minutes. The reaction mixture was partitioned between water and ethyl acetate, and the organic layer was washed with saturated sodium bicarbonate solution, water, and brine, then dried over magnesium sulfate. The solvent was removed and the residue was purified by silica gel chromatography, eluting with (0-100% EtOAc/hexanes) to give the title compound as a white solid (190 mg). MS (ESP): 410 (MH+) for C21H20FN5O3;