Reaction Steps
In step 16-4, potassium fluoride (10 g, 175 mmol) and 4-hydroxypiperidine (10.6 g, 105 mmol) were added to a solution of crude (R)-3-(2′-fluoro-2,4′-bipyridin-6-yl)-6-(2-(3-fluorophenyl)pyrrolidin-1-yl)imidazo[1,2-b]pyridazine (16-3) (16.1 g, 35 mmol) in DMSO (100 mL). The mixture was heated overnight to 120° C. (approx. 14 hours). The mixture was filtered through a celite pad and rinsed with EtOAc (1 L). The filtrate was washed with brine, dried over Na2SO4, filtered and concentrated to give a dark oil. The mixture was purified by column chromatography (silica gel, CH2Cl2/CH3OH, gradient 5% to 15%) to yield (R)-1-(6-(6-(2-(3-fluorophenyl)pyrrolidin-1-yl)imidazo[1,2-b]pyridazin-3-yl)-2,4′-bipyridin-2′-yl)piperidin-4-ol (16-4) which was crashed out from CH2Cl2, filtered and dried under high vacuum. 1H NMR (400 MHz, DMSO, ppm): δ 8.30 (s, 1H), 8.22 (d, 1H, J=5.2 Hz), 8.10-8.24 (bs, 1H), 7.90-7.98 (m, 2H), 7.76-7.86 (bs, 1H), 7.52 (s, 1H), 7.40 (q, 1H, J=7.4 Hz), 7.34 (d, 1H, J=5.2 Hz), 7.04 (t, 1H, J=8 Hz), 6.80-6.94 (bs, 1H), 5.19 (d, 1H, J=8 Hz), 4.71 (d, 1H, J=4 Hz), 4.10-4.18 (m, 2H), 3.93-4.06 (m, 1H), 3.65-3.75 (m, 2H), 3.10-3.20 (m, 2H), 1.98-2.10 (m, 2H), 1.78-1.92 (m, 3H), LC/MS: 536.2 (M+H+), 1.34-1.45 (m, 2H). 13C NMR (400 MHz, DMSO, ppm): 163.53, 161.11, 159.53, 153.95, 151.76, 148.27 (d, J=34.7 Hz), 147.69, 147.10 (d, J=25.6 Hz), 146.92, 137.61, 133.14 (d, J=23.2 Hz), 130.34 (d, J=32.4 Hz), 126.54, 126.04, 121.56, 119.26, 118.75, 113.40 (d, J=83.6 Hz), 112.41 (d, J=86.0), 110.26, 109.86, 103.75, 66.34, 61.24, 48.37, 42.72, 35.12, 33.71, 22.65.
