Reaction Steps
6-(5-(Hydroxy(tetrahydro-2H-pyran-4-yl)methyl)-[1,2,4]triazolo[1,5-a]pyridin-2-ylamino)-3,3-dimethylindolin-2-one and 3,3-dimethyl-6-(5-((tetrahydro-21−/− pyran-4-yl)methyl)-[1,2,4]triazolo[1,5-a]pyridin-2-ylamino)indolin-2-one. Thionyl chloride (0.095 mL, 1.303 mmol) in chloroform (1.5 mL) was added to a stirred solution of tert-butyl 6-(5-(hydroxy(tetrahydro-2H-pyran-4-yl)methyl)-[1,2,4]triazolo[1,5-c]pyridin-2-ylamino)-3,3-dimethyl-2-oxoindoline-1-carboxylate (0.441 g, 0.869 mmol) and N,N-diisopropylethylamine (1.286 mL, 7.39 mmol) in chloroform (20 mL) at −45° C. The resulting yellow solution was stirred while slowly warming to 0° C. over 30 min. The resulting yellow solution was recooled to −45° C. More thionyl chloride (0.019 mL, 0.261 mmol) in chloroform (0.3 mL) was added. The resulting yellow solution was stirred while slowly warming to 0° C. over 30 min. The resulting yellow-orange solution was transferred to a separatory funnel with dichloromethane and shaken with saturated aqueous sodium bicarbonate. The layers were separated and the water layer extracted again with dichloromethane. The combined organics were washed with 0.5 M sodium bisulfate in water (2×10 mL), then brine, and then dried over magnesium sulfate, filtered, and concentrated on a rotary evaporator. The residue was dissolved in acetic acid (10 mL) with stirring at room temperature. Zinc dust (<10 micron) (1.136 g, 17.38 mmol) was added. The resulting gray and orange mixture was stirred and heated at 110° C. under a reflux condenser under nitrogen for 1.5 h. The resulting mixture was filtered through Celite and the filter cake washed with 20% methanol in dichloromethane. The filtrate was concentrated on a rotary evaporator. The residue was dissolved in DMSO/methanol, filtered, and purified using reverse-phase preparatory HPLC (15-65% acetonitrile+0.1% trifluoroacetic acid in water+0.1% trifluoroacetic acid, over 30 min). Fractions containing the desired products were loaded onto Strata X—C ion exchange columns from Phenomenex. The columns were washed successively with water, acetonitrile, methanol, and then 5% ammonium hydroxide in methanol. The products came off with the 5% ammonium hydroxide in methanol eluent and were concentrated on a rotary evaporator and dried under high vacuum at 50° C. to give 645-(hydroxy(tetrahydro-2H-pyran-4-yl)methyl)-[1,2,4]triazolo[1,5-a]pyridin-2-ylamino)-3,3-dimethylindolin-2-one (0.148 g, 0.363 mmol, 42% yield) as an off-white solid. 1H NMR (400 MHz, DMSO-d6) δ (ppm) 10.34 (s, 1H), 9.65 (s, 1H), 7.60 (dd, J=7.42, 8.59 Hz, 1H), 7.46 (dd, J=1.37, 8.79 Hz, 1H), 7.41 (d, J=1.95 Hz, 1H), 7.26 (dd, J=1.95, 8.20 Hz, 1H), 7.14 (d, J=8.20 Hz, 1H), 7.05 (d, J=7.03 Hz, 1H), 5.80 (d, J=5.08 Hz, 1H), 5.18 (t, J=4.88 Hz, 1H), 3.84 (ddd, J=3.12, 11.71, 15.23 Hz, 2H), 3.20-3.30 (m, 1H), 3.16 (td, J=1.95, 11.71 Hz, 1H), 2.19 (tq, J=3.86, 11.79 Hz, 1H), 1.70 (qd, J=4.30, 12.49 Hz, 1H), 1.51 (qd, J=4.49, 12.43 Hz, 1H), 1.39 (d, J=11.71 Hz, 1H), 1.31 (d, J=12.49 Hz, 1H), 1.23 (s, 6H); MS (ESI) m/z 408.3 [M+1]+. 3,3-Dimethyl-6-(5-((tetrahydro-2H-pyran-4-yl)methyl)-[1,2,4]triazolo[1,5-a]pyridin-2-ylamino)indolin-2-one (0.055 g, 0.140 mmol, 16% yield) was also isolated as a white solid. 1H NMR (400 MHz, DMSO-d6) δ (ppm) 10.33 (s, 1H), 9.63 (s, 1H), 7.47-7.54 (m, 1H), 7.43 (dd, J=1.37, 11.52 Hz, 2H), 7.27 (dd, J=1.95, 8.20 Hz, 1H), 7.14 (d, J=7.81 Hz, 1H), 6.91 (d, J=7.03 Hz, 1H), 3.84 (dd, J=2.34, 11.32 Hz, 2H), 3.26 (t, J=10.93 Hz, 2H), 3.04 (d, J=7.42 Hz, 2H), 2.16-2.31 (m, 1H), 1.52 (d, J=11.32 Hz, 2H), 1.36 (qd, J=4.30, 12.10 Hz, 2H), 1.23 (s, 6H); MS (ESI) m/z 392.3 [M+1]+.
