To a solution of 5′-methyl-6-(3-methyl-1H-pyrazol-1-yl)-3,3′-bipyridine-5-carboxylic acid (5-2, 0.025 g, 0.085 mmol) and 1-(1-methyl-1,2,3,4-tetrahydroquinolin-6-yl)methanamine (0.015 g, 0.085 mmol) in ACN (0.85 mL) was added 1-propylphosphonic acid cyclic anhydride (T3P, 0.15 mL, 0.255 mmol) followed by Hunig's base (0.089 mL, 0.51 mmol) and the system was stirred at 40° C. for 1 h in an oil bath. The reaction mixture was cooled and partitioned between EtOAc and water, washed with saturated sodium bicarbonate and dried over magnesium sulfate. The reaction mixture was filtered, concentrated and purified via normal phase chromatography (0→10% MeOH in EtOAc) to afford the title compound (5-3) as a bone powder. 1H NMR (500 MHz, CDCl3) δ 8.68 (m, 1H), 8.51 (m, 1H), 8.29 (m, 1H), 8.22 (m, 1H), 7.72 (m, 1H), 7.12 (m, 1H), 7.0 (m, 1H), 6.90 (m, 1H), 6.54 (m, 1H), 6.27 (m, 1H), 4.46 (m, 2H), 3.22(m, 2H), 2.88 (s, 3H), 2.74 (m, 2H), 2.44 (s, 3H), 2.28 (s, 3H), 1.97 (m, 2H). HRMS [M+H] C27H28N6O calc'd 453.2391, found 453.2397.
